Geologic atlas of the Benevolence, Lumpkin, and Richland, Georgia 7.5 minute quadrangles [2004]

GEOLOGIC ATLAS OF THE BENEVOLENCE, LUMPKIN, AND RICHLAND, GEORGIA 7.5 MINUTE QUADRANGLES
Mark D. Cocker
In cooperation with the United States Geological Survey Cooperative Agreement #03HQAG0083
DEPARTMENT OF NATURAL RESOURCES Noel Holcomb; Commissioner
ENVIRONMENTAL PROTECTION DIVISION Carol Couch, Director
GEORGIA GEOLOGIC SURVEY William H. McLemore, State Geologist
Open File Report 04-1
Atlanta 2004

GEOLOGIC ATLAS OF THE BENEVOLENCE, LUMPKIN AND RICHLAND, GEORGIA 7.5 MINUTE QUADRANGLES
(United States Geological Survey Cooperative Agreement #03HQAG0083) ABSTRACT
As part of the United States Geological Survey's STATEMAP Project, the Georgia Geologic Survey prepared three 7.5 minute quadrangle geologic maps during 2003 and 2004. The current report contains descriptions of the stratigraphic units which have been identified and mapped in the Benevolence, Lumpkin and Richland quadrangles, information on aquifer recharge zones, geologic hazards, and kaolin deposits.
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CONTENTS INTRODUCTION................................ ....... ....... ... .. ... ........... ... ... ......................... .. .. .. .. .. ............. ... ........... ... .. .. ............... 1
Scope of the mapping project .............. ... .... ......... ...... ................... ..... .......... ... ........ .................. ..... ..... .. ............. ... ... 1 Methods.. .... .. .. ...... .... .. .... ........ .................................... .... ... .. ... ........ .. .......... .. ....... .. ........ .............. ....... ... .. .. ............... l Previous investigations ..... ... ... ............. ....... .......... ... .............. .......... ..... .. ..... .. .... ... ...................... ....... .... ...... .... .. ...... 5 PHYSIOGRAPHY AND LAND USE ... ............ ...................... ..... ........... ...... ..... ... ................. ........... .......... .. .. ............... 6 SOILS ....................... ............ .. ...... ... ........ ........ .... ...................... ......... ........ .............. ..... ................................ ................... 7 GENERAL GEOLOGY .............. .................................. ..... .. .... ........ .......................... ........... ..... ...... .......................... ..... 8 Geologic cross-sections ... ......... ...................................... .................................. ........................................................ 9 STRATIGRAPHY OF THE BENEVOLENCE, LUMPKIN AND RICHLAND QUADRANGLES ........................... 11 Upper Cretaceous .. ............. ....... .. .. .. ....... ................................................ ..................... ....... ... ..... ................ .......... ... . 11
Selma Group ............ .. .. ........ .. .. .. .... .. ...... .... ........................................................ ..... ............. .. ... .......... .... .......... 11 Cusseta Formation (Kc) .. .. .. ..... .. ....... ..... .... ........ .. ................ .... ..... ............................................................. 11 Ripley Formation (Kr) .... .. .. ........ ... ........................... ......... ........................................... ..... .......... ......... ..... 12 Providence Formation (Kp) ....... ....... .............. .... .... .............. ....... ... .............. ... .. .. ...... ....... ............ .. .... ....... 14
Lower Paleocene ........................ ...... ... ...... .. .... .... ........... ...... .. .... ........... .... ......... .... ... ..... .......... .... .. .. .............. ......... 19 Midway Group ...... ................................... ......... ........................................ ............... ................................ ... ...... 19 Clayton Formation (Tel) ........... .. ... .... ........... .... ........ ... ............ .................. ... .......... .... ..................... ......... . 19 Porters CreekFortmation (Tpc) ............................................................... ................................................... 28
Upper Paleocene to Lower Eocene .............. ... ......................................................................................................... 28 Wilcox Group ............ .......... .. .... ........... ... .... .................................................................... .... ....... ...................... 28 Nanafalia Formation (Tnf) .. ........................... .. .. .. ............... .. .. ... ........ .............................. .... ...................... 28 Tuscahoma Formation (Ttu) ............. ... ................ ... ..... ........... ..... .. .................. .. ... ..... ...... ... ........... ............ 32 Hachetigbee Formation- Bashi Marl Member.. ... ... ...................... ....... ................. ..................................... 32
Lower to Middle Eocene ....... ... ... ..... ... ............... ..... ..... ... ... ....... ............ .. ............ .......... ... ... ..... ........................... .. ... 32 Claiborne Group (Tcb).............. ........ ...... ...... ..... ... ... .. .. ... ..... .............. ..... ... ... ...... ..... ...... .... .................. ......... .... .. 32 Lisbon Formation (Tl) ...................... ...... ........... ... .................. ... ...... ............ ..... ................................................ 32
Upper Eocene ......................................................................................................................................................... .. 34 Eocene to Oligocene ................................................................................................................................................ 34
Tertiary Sediments and Residuum (Tsr)............................................................................................................ 34 Miocene ................................................................ .. ........ ...... ... .. ......... ..._......... ... ... ... .. ...... .. ....................... ............... 36
Altamaha Formation (Ta) ..... ...... .. ......... ........ ......... ..... .. ........ ........ ..... ..... ...... .................................................... 36 Quaternary................... .............. .............. .. ....... .... .. ... ........ ................. ........ .. ..... ........... .. .......... ... .. ... ....... ..... ............ 51
Quaternary Alluvium (Qal) ........... .. ... ............. ... ................. ..................... .. ..... ...... ... .... .............. ........ ............ .... 51 Alteration of primary sedimentary textures ........................................... .. .. .. ...... .......... ... .... ........ .... .. ........................ 52 Correlation of STATEMAP map units with overlapping 1:100000 scale maps and the 1:500000 scale
Geologic Map of Georgia .............................................. ... ........... ... .. .. .. ... ....... .. .. .. ......... ... ................... .. ........... 52 BIOSTRATIGRAPHY.................................................................................................................................................... 53 STRUCTURAL GEOLOGY ........................................................................................................................................... 55 ECONOMIC GEOLOGY ............................................................................................................................................... 59 HYDROGEOLOGY ... ........... ....................................................... ......... .... ... .. ........................................ ......... ............... 59
Claiborne Aquifer........ ...... ......... .............. .......... ......... ........... ..... .......... .. ..... ...... .... .. ......................................... ....... 60 Clayton Aquifer........ ..................... ................. ............................................. ............ .. .............. .......... .. .................. ... 60 Cretaceous Aquifers ....................................... ... ..... ....... ........................................... .... ........... .............. ....... .... .... .. .. 61 EVIDENCE FOR PAST GROUNDWATER MOVEMENT .. ....................................................................... .. ............. . 62 GEOLOGIC HAZARDS ..... ........ ....... ........... ......... ........ .. ... .... .. ...... ............ ...... .......... .... .... ... ............... .. ..... .......... ..... .. .. 64 SUMMARY .......... ....... .... ...... ...... .. ............... .......... ...... ............. ................ ............. .... ....... ... ......................... .......... .... .. 67 REFERENCES CITED .... ... .. ... ...... .... ................... ... ........ ... ..... ... .... ............ ... ........ ..... .... ....... ....... ..... ................... .......... 68 APPENDIX ................ ... .. .. .. ... ................................... ................ .... ... ................ .... .... ..... ........................ ....... ................. 72 Drill hole logs for the STATEMAP program (February, 2004 through April, 2004) .............................................. 73
FIGURES
1. Location of the Lumpkin project area in relation to the most significant recharge areas......................................... 2 2. Map of Georgia showing location of STATEMAP mapping and previous 1:100,000-scale Upper Coastal Plain geologic mapping.. .. .... ......... .. ... ... .. .. ........ .. ........ ............. ...... ...... ....... ..... .. ... ... .... .................. ......... ... ........ 3
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3. Stratigraphy and related aquifers in or adjacent to the current map area.................................................................. 4 4. Summary descriptions of the map units in the current map area.............................................................................. 5 5. Interbedded sandstone and brown clay of the Cusseta Formation.................................. .. ............... .. .............. .. ....... 12 6. Outcrop of Ripley Formation (Kr) underlying Providence Formation ..................................................................... 13 7. Closeup view of highly fossiliferous Ripley Formation in Fig. 6 ....... .. ................................. .. .......... .. ...... .. ..... ..... .. . 13 8. Coarse-grained cross-bedded sandstone of the Providence Formation .. ............. ...... ... ... ........... .. ........................ .... 15 9. Iron oxide stained, massive appearing Providence Formation .. ........ .... .......... ...... ... ........ ...... ............. .............. .. ..... 15 10. Steep escarpment caused by rapid erosion of the soft Providence Formation ......................................................... . 16 11. Steep escarpment caused by headward erosion of Providence Formation ... .. ... .. .. ............ ..................... .. ... ............. 16 12. Ophiomorpha casts in cross-bedded Providence Formation... ..... .. .... .. ... ......... ..... .. ................................. ...... ........... 17 13. Bed containing abundant Ophiomorpha burrows in cross-bedded sandstone of the Providence
Formation ............. ... .. .... .. ... .. ...... ............... .... ... .......... ... .. ... ... ... ... ....... .. .. ... ... .... .... ...... ... ... ...... .......... ...... ........ .. ...... .. 17 14. Hard kaolin in upper part of the Providence Formation .. ...... ...... ...... .. ... ........... .......... ...... ..................... ................ .. 18 15. Shale and clay clast-rich breccia/conglomerate (?) at contact between the Clayton and Providence
Formations .. .. ...... ....... .. .......... .......... .. ........ ... .... ... ...... .. ... ... ... .... ..... .. ...... ... ... ... ...... .. ....... ... .. .... ............................... .. 18 16. Clay and iron oxide boulder residuum of the Clayton Formation underlying Altamaha Formation......................... 20 17. Clay, iron oxide and chert (white fragments) of the Clayton Formation ...... .. ...... .... .... .. .. .. ..................... .... .. .. .. .. ..... 20 18. Clay with iron oxide mass of the Clayton Formation underlying sandstone of the Nanafalia Formation.... .. .... .. ..... 21 19. Contorted bedding, clay and iron oxide masses in Clayton Formation ........ .. ...... .................... .... ........ .. .. ........... .. ... 21 20. Clayton Formation clay underlying Nanfalia and Altamaha Formations.. .... ..... .. .... .. .......................... ............. ... .. ... 22 21. Contorted bedding at contact between Clayton and Nanafalia Formations ............................. .. .......................... .. ... 22 22. Unusual kaolinization of Clayton Formation(?) underlying iron oxide clast-rich Altamaha Formation.................. 23 23. Contorted clay and iron oxide clasts in Clayton Formation ... ............. ...... .. .. ...... ................. ......................... ... .... .... 23 24. Thin Clayton Formation clay between underlying Providence Formation and overlying Nanafalia
Formation ................................................................................................................................................................. 24 25. Slightly thicker Clayton Formation with lower clay and upper iron oxide rich layer between underlying
Providence Formation and overlying Altamaha Formation.... .. ........ .. ............ .... ....... .. ...................... ............. .. .. ...... 24 26. Clayton Formation clay overlying Providence Formation and underlying Altamaha Formation .. .... .... .. .. .. .. ........... 25 27. Closeup view of Clayton Formation- Providence Formation contact in Fig. 26 ............................... ................... .. . 25 28. Closeup view of Clayton Formation- Altamaha Formation contact in Fig. 26 ............. ........ ............... ........ ........... 26 29. Iron oxide rich residuum of Clayton Formation overlying Providence Formation and underlying
Nanafalia Formation.. ......... ... ... ........... .. .... ... ... ........ ............. ... .. ..... ... ... .... ... .... .. ... .. ... .... .. .... ... ... .. .. ............ ....... ........ 26 30. Closeup view of Clayton- Providence Formation contact shown in Fig. 29 ........................................................... 27 31. Channel deposits of Nanafalia sandstone cut into Nanafalia Formation clay and iron oxide residuum ................... 27 32. Massive kaolin of the Nanafalia Formation overlain by Altamaha Formation sandstone ...... .. .. ................ .............. 29 33. Altamaha Formation sandstone with basal conglomerate overlying cross-bedded kaolinitic sandstone
and massive kaolin of the Nanafalia Formation ....................................................................................................... 29 34. Kaolin clasts in sandstone of the Nanafalia Formation and contact with overlying Altamaha Formation
sandstone .................................................................................................................................................................. 30 35. Tuscahoma - Nanafalia Formation contact cut by Altamaha Formation. Lower Altamaha Formation
contact intersects road surface downhill to the right ........................... .. .............. .. .............. .... .... .......... .. .. ........ ....... 30 36. Tuscahoma - Nanafalia Formation contact cut by Altamaha Formation. Tuscahoma - Nanafalia
contact dips to the west (right) ....... ...... ... ................ ... .................. ............... .......... .. ..... ... ... .... ...... .......... .. ........ .... ... 31 37. West dipping contact between clay, shale, and silt of the Tuscahoma Formation and overlying
Claiborne Group sandstone .... .. ................. .... ........... ... ... ... ... ...... ........... ....... .. ..... ... .. .. ... ... ... ........ ............ .. ....... ........ 31 38. West dipping kaolinitic sandstone with kaolin clasts of the Claiborne Group ............................. ... ..... .. .................. 33 39. Intermixed fme-grained sandstone, shale and shale-clast conglomerate/breccia ...................................................... 35 40. Close up view of clay and shale clast-breccia in Fig. 39 .......................................................................................... 35 41. Massive, brick-red sandstone of the Altamaha Formation overlying massive, brick-red sandstone of the
Claiborne Group (?) .. .. ... .. ........... .............. ... ... ... ... ... ... ... ... .. ... ... ... .. ....... ... ......... ..... .. ... ..... ....... .... ........... .................. 39 42. Lower contact of the Altamaha Formation marked by thin conglomerate containing clasts of iron oxide
and iron oxide cemented sandstone, as well as ironstone pebbles.. ........ ............... .......... ..... .. ..... ... .... .. ... ................ 39 43. Steeply dipping contact between Altamaha Formation and underlying Providence Formation. ... .. ....... .... .... ..... .. ... 40 44. Oblique view of Altmaha- Providence Formation contact... ................................................................................... 40 45. Unconformable contact between Altamaha and Providence Formations .. ..... ...... ......... ... ....... .. .. .................. .... .. ..... 41 46. Closeup view of platy, iron oxide-cemented sandstone clasts in basal conglomerate at Altamaha -
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Providence Formation contact shown in Fig. 45 .... ............................................ .... ............................. .................... . 41 47. Steep, north dipping, unconformable contact between the Altamaha and Providence Formations ... ........ ... ....... ..... 42 48. Steep, south dipping, unconformable contact between the Altamaha and Providence Formations .. ........................ 42 49. Clast-rich, channel of the Altamaha Formation cut in Providence Formation........ ....... ........ ... ..... .... .......... .... ......... 43 50. Altamaha Formation with clast-rich basal conglomerate forming channel cut in Providence Formation................. 43 51. Clast-rich basal conglomerate of the Altamaha Formation overlying north dipping Providence
Formation ................................................................................................................................................................. 44 52. Steep angular contact between Altamaha Formation sandstone and Clayton Formation clay .. .................... ............ 44 53. Uppermost "terrace" of Altamaha Formation sandstone overlying sandstone of the Providence
Formation ................................................................................................................................................................. 45 54. View of upper Altamaha Formation "terrace" with angular down cutting into Providence Formation to
next "terrace"....................................................................................................................................................... .... 45 55. Close up view of angular cross-cutting Altamaha Formation with basal conglomerate .......... ............................ .... . 46 56. Third lowest "terrace" of Altamaha Formation cutting Providence Formation ........................................................ 46 57. Lowest (fourth) "terrace" of Altamaha Formation that cuts Providence Formation....... .. .................................... .... 47 58. View uphill from level of fourth "terrace" showing position of higher terraces, the vertical relief
between the different terraces.................................... ............................................................................................... 47 59. View uphill of terraces and channels of Altamaha Formation cut into kaolinitic sediments of the
Nanafalia Formation......... ............................................................................................ .......................................... .. 48 60. Terraces and channels of Altamaha Formation cut into kaolinitic sediments of the Nanafalia Formation
viewed downhill ................................................................................................... ........... .......... ......... ............ .......... 48 61. Close up view of Altamaha Formation channel shown in Figs. 59 and 60 cutting across bedding in
Nanafalia Formation........................................................................................................................................ .... ..... 49 62. Close up view of erosional remnant of the Nanafalia Formation with Altamaha Formation overlying
and cut across bedding in Nanafalia Formation ..................... ........................ .. ............. .. ........ ................................. 49 63. Fine-scale layering near base of the Altamaha Formation. .................. .. .. ............................ ..................................... 50 64. Intensive ground water weathering of the Altamaha Formation ................................ .. .. ........... ..... ....... .................... 50 65. Unidentified tubular, bone-like fragments in Altamaha Formation .......................................................................... 51 66. Diapir of Clayton Formation (Tel) clay cut into Nanafalia Formation (Tnf) sandstone ........................................... 56 67. Two diapirs of Clayton Formation (Tel) clay cut into Nanafalia Formation (Tnf) sandstone ............................... ... 56 68 . Diapir of Clayton Formation (Tel) clay cut into Nanafalia Formation (Tnf) sandstone ........................................... 57 69. Synclinal fold of Clayton Formation (Tel) clay overlying Providence Formation (Kp) sandstone ...................... .... 57 70. Synclinal fold of Altamaha Formation (Ta) sandstone overlying Providence Formation (Kp) sandstone ........ ....... 58 71. Synclinal fold in Providence Formation (Kp) sandstone overlain by unfolded Altamaha Formation (Ta) .............. 58 72. Iron oxide cemented, cross-bedded, Providence Formation sandstone ................ ...... .............................................. 62 73. Iron oxide stained and cemented sandstone above more indurated iron oxide cemented sandstone layer
in Providence Formation ................... ....... ................ ... ... ..... ........... ... ....... ... .... ........ ... ... ....................... ...... .............. 63 74. Two, tilted, temporally separate mottled zones developed in Altamaha Formation sandstone......... ....................... 63 75. Erosional downcutting into soft Claiborne Group sandstone resulting from runoff from highway
culvert .................... .. ........... ..................... .... ........ .. ..... ............................................... ............ ............. .................. 65 76. Deep pit eroded in soft Claiborne Group sandstone by runoff from highway culvert .............. ............ ...... .............. 66
TABLES 1. Percentage of quadrangle containing map unit polygons .. ... ....... .... .... ... ..................... ... ......................................... . 10 2. Comparison of STATEMAP stratigraphic terminology with that of the Americus geologic map of
Reinhardt and others (1994) ...................................... ....... ..................... ....... ............. ......... .... ..................... ............. 53 3. Macrofossils identified from the Ripley Formation (Almand, 1961) ............. ............................ .. ... .................. ... .. . 54 4. Kaolin analyses ....... ............... .. .. .................. .............. ..... .......... ..................... ..... .............. ........... .... .... ...... ... ... ........ 59 5. Aquifer characteristics in the study area.............................................................................. ..................................... 61
PLATES 1. Geologic map of the Lumpkin 7.5 minute quadrangle. 2. Geologic map ofthe Richland 7.5 minute quadrangle. 3. Geologic map of the Benevolence 7.5 minute quadrangle. 4. Geologic cross-sections
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INTRODUCTION
Scope of the mapping project
The Georgia Geologic Survey mapped the surface geology of the Benevolence, Lumpkin and Richland 7.5 minute (1:24,000 scale) quadrangles in the Upper Coastal Plain of southwestern Georgia from October, 2003 through August, 2004. Mapping included both traditional field mapping and development of GIS digital databases for each quadrangle in Arclnfo format. Mapping was part of the Georgia Geologic Survey's STATEMAP Project (in cooperation with the United States Geological Survey, Cooperative Agreement #03HQAG0083).
The Georgia Geologic Survey's STATEMAP Project involves the geologic mapping of significant aquifer recharge zones in the Upper Coastal Plain (Fig. 1). These recharge zones include those of the Cretaceous, Clayton, Claiborne, and Upper Floridan aquifers. Previously funded STATEMAP mapping in Georgia (Fig. 2) included 18 quadrangles of the Americus area and compilation of that mapping as a 1:100,000 scale geologic atlas of the Americus area. Figure 3 provides a summary of the stratigraphy and related aquifers in or adjacent to the Lumpkin area.
Methods
Field methods used to produce the geologic maps (Plates 1 through 3) involved mainly the description and mapping of roadside outcrops and exposures. In addition to the geologic mapping, lithologic descriptions of well cuttings from the Georgia Geologic Survey technical files and published descriptions from Herrick (1961) were used to help construct the geologic cross-sections illustrated in Plate 4. The Georgia Geologic Survey drilled a series of shallow core holes (less than or equal to 50 feet) that were designed to: 1) confirm the mapped geology, 2) determine depth to contacts, and 3) examine relatively non-weathered lithologies particularly in areas with limited exposures. Descriptions of these cores are in Appendix I.
A significant part of this project involved production of digital mapping products. Outcrop locations were digitally plotted directly from field maps using Arclnfo 8.1. Additional field geologic data were compiled in an Arclnfo database. Digital geologic maps were compiled on-screen using the outcrop data and cross-sections (Plate 4). Arcplot programs were written to prepare hard copies of each individual geologic map (Plates 1 - 3). Geologic cross-sections were constructed on gridded mylar, scanned, digitally traced and graphically completed in CorelDraw 7.0. Documentation regarding the development of the Arclnfo databases as well as Arclnfo export files of those coverages are in preparation. Development of the Arclnfo databases for the current map area generally follows the procedures documented for the previous STATEMAP quadrangles in Georgia (Cocker, 1999b, c, d and 2000a, b, c, d).
Lithologic descriptions and stratigraphic terminology (Fig. 4) for this portion of the Lumpkin STATEMAP Project generally follow that of Cocker (2003b), Hetrick (1990), Marsalis and Friddell (1975), and Reinhardt and others (1994).

Tennessee
Florida
Figure 1. Location of the Lumpkin project area in relation to the most significant groundwater recharge areas. The most significant groundwater recharge areas are shaded.
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EXPLANATION
Map covemge @ 1: 100,000 scale
Wrens-Augusla (GGS, Hetrick, 1992) Kaolin District (GGS, Hetrick and Friddell, 1990) Fort Vctlley (GGS, Hetrick, 1990)
Ill Butler (GGS, Hetrick, 1996)
; -; Americus 30' x 60' (USGS, Reinhardt and others, 1994)
Map coverage @ 1:24,000 scale
0 Americus Project- STATEMAP (completed 2003)
Lumpkin Project- STAJEMAP

N
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Scale (approximate)

~

5(J miles

Figure 2. Map of Georgia showing location of STATEMAP mapping and previous 1:1 000,000-scale Upper Coastal Plain geologic mapping.

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Period Quaternary

Epoch Recent Pleistocene Miocene Eocene to Oligocene

Formation
unnamed stream alluvium
unnamed stream alluvium
Altamaha Formation
Residuum from Eocene and Oligocene limestones and perhaps units as old as
the Lisbon Formation

Group
Vicksburg Group

Aquifer

Paleocene

Perry Sand /Lisbon Formation Tallahatta Formation
Hatchetigbee Formation
Tuscahoma Formation* Nanafalia Formation
Porters Creek Formation Clayton Formation Providence Sand Ripley Formation
Blufftown Formation

Claiborne Group
Wilcox Group
Midway Group

Claiborne aquifer
Clayton aquifer Providence aquifer
Cusseta aquifer Eutaw-Blufftown
aquifer

Comanchean

Eutaw Formation Tuscaloosa Formation
undifferentiated

Eutaw Group Tuscaloosa Gp.

F1g. 3. Stratigraphy and related aqUifers m or adJacent to the current map area. (* Upper part of Tuscahoma Formation may be Lower Eocene in age).

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Quaternary llllu'l'ium -variably mi.:a~'<:'OLU! and clayey, poorly-sortlld, silt. ~md, and quurtz gravel.
A U:unoh:l F'ortmntlon - dmninomly mn.;sivc, brick- red. argill>acc<)Lu; Slmd.o;llnll and mottled clay-rich fiandstoncs 1\ ith p.:Jtlo ~~~bbl.! (111r~)- , ~...! ir m~l\1111! d ,ast,. unco nmtt~lljllnr!l'. pchbl o.~ beds, nnd rnr.: l.!hcrt clasts. Conglooreratic layer o.:nmmm ly thund 111 IJW~r <XJI11ll~ l wirh 'lib<Jrq.: (.nmp sands contains ironstone du.~i~ and quUJtz (ll!bhlcs. and lo 'tl ll~ irqu o:-.id.: CI'L\~ 1. nud rtlu utl~d, ~bblc to boultklr- izl!d clasts of sandstone apparently
or d~rlv.:d fn)ll \ .:rosion IU1d<!rl~ing Cl:rilxmu: Gruup .:dhn~nl~.
Tertiary Sediments and Rcsidtwm- variably waxy to slightly silty clays that commonly include abundant chert.
Ro:mowd b) erosion or not recoguizl!d; may be pmt oftll<J Tertiary Sediments and Residuum.
{1. flmnu. Grt~up: P4'1'1'. Sn11d - me- to a:~rne.- gra ined. massiw- to ~Tos.~-b.:dd~d snmlgradilll:\ d 1 ud ip to Lisbon Formation. t.ls hon 'nrmn tlon - calt'1lr.:ott , ~nndy .:luy. d:ry~')' linm~ IUld llm.:!<IOII~ Tnllu l11lfta rmm1llon- mm 'iv.:- I<' cro~~-b dd~<~ fine 111 cn.!lrsc-gro ned. li n ci~' laycr.:ld to .:rof!.~bedded sand and ~al'l(l~r ..m: int~rl ay<~rcd wi1h lll'l lhin ~hul"' h ~Lt!ldY hut.~. f'..:rr y Sand nr:t, Lie 1:-<JUiHii dut to Tilllahattn Fonnation. Tu <'nhntnll Fn1T11atioo- nonfD!l.~ilifllrous, carbonaceous, clay, silt. and sand overlying and laterally grading iuto ~ro -bcdd'oo, micac<lous. ca!.:areous, fossilifdroiL~. mo:dium- to coarse-grain<!(( sand. Nanotialia Fom~~~tion- micaceous, ma~;.<;ivc-ll<lddcd, glauconillc, fossiliferous, calcar.zou~. line- to coarse-grained sand with local clay len-.
Portcn Creek Fom1atron- i<l~;.~lliferous, glauconitic. fL~sik, WILXY to varla l,ly ~illy clay.
Clayton Fmmqtioo- sandy, micritic. biocla~tic limes ton<' with inter-b.:dd.:d silt~ clay and calcareous sandstone.
Provldm('e FoniUltkm- koolinitic, eross-beddo:<L nwdium- coars.:-gmin~>d smtd and sandston.: with I~a1koolin
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Ripley Fom1:~tion - massiv.:. micaceou~ and glauc.onitic, tine- grained sand and silty clay Cutieta Fornmtion- eross-b.:dd<ld. l~nlly kaolinitic, m.:<lium to coarsll-grained sand

Figure 4. Summary descriptions of the map units in the current map area. The Perry Sand and Lisbon Formation may be present in the subsurface but have not been recognized on the surface.
Previous investigations
Recent regional scale maps (1:100,000) are located in relation to the STATEMAP quadrangles in Fig. 2. The quadrangles mapped during this current project overlap a portion of the geologic map of the Americus 30' x 60'

5

quadrangle (Reinhardt and others, 1994) and are adjacent to the Americus geologic atlas (Cocker, 2003b). The earlier mapping by Reinhardt and others (1994) does do not differentiate strata above the Tuscahoma Formation (Paleocene) and are thus difficult to correlate with the younger strata found in the current map area.
The Geologic Map of Georgia (Georgia Geologic Survey, 1976) and the 1:500,000 scale Digital Geologic Map of Georgia (Cocker, 1999) provide a general view of the surface geology of the map area. Digital overlays of the geology and topography at 1:24,000 scale display a rough correlation between the 1:500,000 scale geology of the state map and the detailed topography.
The geology of the Lumpkin quadrangle was studied and mapped by Almand (1961). A number of outcrops described in Almand's thesis appear to have degraded or been significantly modified by highway construction in the nearly 45 years since that quadrangle was mapped.
Other geologic investigations in or near the present map area are concentrated mainly on the stratigraphic sections exposed along the Chattahoochee River. Geologic reports that provide pertinent information or aid in interpretation to the present mapping include local and regional studies by Beck (1982), Bybell and Gibson (1982), Cocker (2001, 2002, 2003a, b), Cocker and Costello (2003), Cofer and Fredericksen (1982), Cofer and Manker (1983), Cramer and Arden (1980), Eargle (1955), Fallaw and Price (1992), Fritz (1989), Gibson (1982), Gohn and others (1982), Herrick and Vorhis (1963), Hetrick (1990, 1992, 1996), Hetrick and Friddell (1990), Huddlestun (1985, 1988, 1992a, b, 1993), Huddlestun and Hetrick (1979, 1985, 1991), Huddlestun and others (1974), Kirkpatrick (1959, 1963), Marsalis and Friddell (1975), Nystrom and Willoughby (1982), (Owen (1956), Reinhardt (1982, 1986), Reinhardt and Gibson (1981), Toulmin and LaMoreaux (1963), and Zapp and Clark (1965).
Subsurface geologic investigations of the study area include descriptions of well logs and hydrologic reports. Lithologic descriptions of core samples and cuttings from wells in Stewart and Randolph Counties were obtained from published data by Herrick (1961), and unpublished drill logs by Herrick and anonymous authors (Georgia Geologic Survey technical files, Atlanta, Georgia). Clarke and others (1983, 1984), Gorday and others (1997), Johnston and Miller (1988), Long (1989), McFadden and Perriello (1983), Mitchell (1981), Reinhardt (1982), and Vorhis (1972) examined the hydrology and hydrogeology of the region.
The general relationships of soils in Terrell and Sumter Counties to the parent source rocks as depicted on the geologic maps for the Bottsford, Dawson, Parrott and Shellman quadrangles (Cocker, 2001) are similar for most of the soils in the Benevolence and Richland quadrangles. Soils in the Lumpkin quadrangle were derived to a great extent from older, poorly cemented sands and silts
PHYSIOGRAPHY AND LAND USE
The Benevolence, Lumpkin and Richland quadrangles lie within the Coastal Plain Physiographic Province. Terrain in portions of the Benevolence and Lumpkin quadrangles is characteristic of the edges of the Dougherty Plain physiographic district and consists of gently to moderately rolling upland surfaces incised by Ichawaynochaway Creek, a tributary of the Flint River. Several major streams, Colochee, Day, Hannahatchee, Hodchodkee, and Pataula Creeks and their tributaries, belong to the Chattahoochee drainage system and have incised deeply into soft sandstones particularly in the Lumpkin and western portions of the Benevolence and Richland quadrangles. Terrain in these areas can be quite dramatic with cliff-like escarpments and relief on the order of several hundred feet. This hilly terrain is characteristic of the Fall Line Hills physiographic district. Stream
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valleys are generally wide and flat, typically on the order of 0.25 to 0.5 miles wide, with relatively steep slopes. Many parts of the upland interfluvial areas, particularly in the Benevolence and Richland quadrangles, are covered by a relatively thin layer of indurated argillaceous sandstone of the Miocene Altarnaha Formation. This sandstone has served as a cap rock protecting significantly softer sand, siltstone and sandstone of the underlying Claiborne Group, Tuscahoma and Providence Formations. Breaching of the Altarnaha sandstone cap resulted in rapid down cutting and erosion of the underlying sand and silt. New base levels have apparently been established in the major stream valleys. Elevation of the upland (interfluve) areas rises gradually from 450 feet in the southeast part of the Benevolence quadrangle to 650 feet in the northeastern part of the Lumpkin quadrangle. Base level of many of the major streams is about 350 feet. Relief is accentuated in the northwestern parts of the mapped area because of the differences in elevation between the interfluve areas and stream base levels. Much of the bottornlands in the major stream valleys are relatively swampy and are underlain by the shales and clays of the Tuscahoma Formation or the Ripley Formation.
Interfluve areas within the Benevolence, Lumpkin and Richland quadrangles are mainly used for agricultural products which include peanuts, com, soybeans, cotton, pecans, beef cattle, hogs, sawlogs, and pulpwood. Many large tracts of land are also used by hunting clubs. Lumpkin and Richland are the principal population centers. Population has been declining in Stewart County since the early part of the 1900's.
SOILS
Although agriculture is the major industry in the current map area, this area is relatively sparsely populated. The relatively flat interfluve areas that extend from just north and east of Richland, directly west to the eastern side of the Lumpkin quadrangle and south to the southern edge of the Benevolence quadrangle are best suited for agriculture because of the soil and topography. Most of the land in the Lumpkin quadrangle and western part of the Richland and Benevolence quadrangles is poorly suited for agriculture. This section briefly describes the soils in regards to their source materials and the information the published soil data can contribute to geologic mapping in the area.
Soils m the map area reflect intensive subtropical weathering of the exposed Tertiary and Cretaceous stratigraphy. Soils in upland, interfluve areas (Plates 1 - 3) are derived mainly from gravelly sands and sandy clays of the Altarnaha Formation. Generally sandy soils are found in the tributaries of the Chattachoochee River, essentially in the western part of the current map area and in places where the Altamaha Formation has been breached by erosion such as in the Ichawaynochaway Creek drainage basin in the Benevolence quadrangle (Plate 3). These sandy soils are derived principally from sandstone of the Claiborne Group, the Nanafalia Formation, the Providence Formation and the Cusseta Formation. Clay rich soils are derived from the Tuscahoma, Clayton and Ripley Formations, but are relatively restricted in their areal distribution, however.
Soils may be classified based on diagnostic surface horizons, epipedons, and subsurface horizons. The principal types of soil found in the southeastern United States are Ultisols. This soil order is characterized by argillic or kandic horizons and low base saturation. An argillic horizon is defmed as a subsurface accumulation of high-activity silicate clays that have moved downward or translocated from the upper horizons or have formed in place (Brady and Weil, 1999). An epipedon overlying a kandic horizon has commonly lost most of its clay content. A kandic horizon is a diagnostic subsurface horizon characterized by an accumulation of iron and aluminum oxides as well as
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low activity, strongly acid, silicate clays (e.g., kaolinite). Low activity clays demonstrate low cation-holding capacities (< 16 cmolclkg clay). Clays are often found as coatings on pore walls and surfaces. Ultisols formed under conditions of fluctuating wetness have horizons of iron-rich mottled material called plinthite. As long as it remains moist, plinthite is soft and easily dug. When exposed and dried in air, plinthite hardens into an ironstone. Ultisols are formed under wet, tropical conditions and usually under forests. Most are developed on old land surfaces (Brady and Weil, 1999).
Intensive subtropical weathering has produced a commonly striking profile in the soils and subsoils, particularly in those derived from the Altamaha Formation and, to a lesser extent, those derived from the Tertiary Sediments and Residuum unit. The upper portion of the profile is commonly sand-rich or slightly argillaceous sand/sandstone. This portion of the profile may range from 0 to 5-10 feet thick. Thickness of this sandy portion of the profile is commonly dependent on the degree of erosion (Long and Baldwin, 1915). A clay rich zone is generally found beneath the upper sandy zone or may be present by itself with the upper, sandy unit having been removed by recent erosion. Clay particles are mobilized by downward percolating surface water and accumulate in the subsoil. Mottling, probably related to oxidizing ground water, is usually developed in the clay rich lower zone. Irregular concentrations of iron-oxide cemented sediments (plinthite) may be developed in this lower clay-rich zone. These have formed in situ and result from remobilization of iron from other parts of the soil and subsoil. Cocker (2001) described and interpreted the vertical distribution of particle sizes in the main soil types of the Bottsford, Dawson, Parrott and Shellman quadrangles just to the east of the current map area. These relationships should generally exist in the Benevolence and Richland quadrangles where the Altamaha Formation is located.
GENERAL GEOLOGY
The surface geology of these three quadrangles is quite varied, ranging from principally younger Tertiary strata in the central to eastern and southern parts of the Benevolence and Richland quadrangles to remnants of Tertiary strata amongst dominantly Cretaceous rocks in much of the Lumpkin quadrangle. The western parts of the Benevolence and Richland quadrangles and the eastern part of the Lumpkin quadrangle are a transition from the dominantly Tertiary to the dominantly Cretaceous strata. Younger sedimentary rocks are generally exposed in the east and south, and because of the regional dip, progressively older units are exposed to the west and north. Erosional unconformities, facies changes, surface weathering, groundwater alteration, lithologic similarities of some sedimentary units, and paucity of outcrops, as well as various combinations of these factors adds complexities to the identification and mapping of the rocks in these quadrangles.
As in the area covered by the Americus geologic atlas (Cocker, 2003b), the youngest Tertiary sediments, represented by predominantly argillaceous sandstone of the Miocene Altamaha Formation, formerly covered most if not all of the present map area. A few, isolated remnants of the residuum of Eocene and Oligocene age sediments, represented mainly by clay and chert, are found in the Benevolence and Richland quadrangles. Generally soft, unconsolidated or poorly cemented sandstone of the Middle Eocene Claiborne Group is found on slopes and on some of the upland areas in the Benevolence and Richland quadrangles. Shale, clay and siltstone of the Upper Paleocene Tuscahoma Formation may be exposed in the larger stream valleys in the Benevolence and Richland quadrangles. Both the Tuscahoma Formation and Claiborne Group appear to thin to the north and west and are
8

generally difficult to fmd or identify in the Chattachoochee River Basin. Kaolinitic, micaceous, cross-bedded sandstone of the Upper Paleocene Nanafalia Formation is found predominantly in the Benevolence and Richland quadrangles and appears to thin to the west and north. A clay and iron oxide residuum of the Lower Paleocene Clayton Formation lies discontinuously above the Providence Formation and is generally poorly exposed. The Clayton Formation appears to thin to the west and north over the current map area.
Progressively older Upper Cretaceous rocks are exposed in the northern and western parts of the current map area. Kaolinitic, micaceous, cross-bedded sandstone of the Upper Cretaceous Providence Formation is found over much of the Lumpkin quadrangle and in the Benevolence and Richland quadrangles where tributaries of the Chattahoochee River have cut through the overlying Tertiary sediments. Soft, fossiliferous clay, silt and marl of the Ripley Formation are found in the northern valleys of the Lumpkin and Richland quadrangles lie above soft sandstone of the Cusseta Formation. Subsurface information regarding the Upper Cretaceous stratigraphic section is sketchy within the present map area and thicknesses of these units are unknown in this area.
Regional dip of the Upper Cretaceous and Tertiary sediments older than the Altamaha Formation is on the order of 10 to 30 feet per mile to the southeast. Locally, sediments and contacts dip to the north and west; this may be attributed to folding in the area. Although the lower contact of the Altamaha Formation is locally very irregular because of an erosional disconforrnity with underlying sediments, it dips generally gently to the southeast, also. The Tertiary section increases in thickness from the west and north to the south and east (geologic cross-sections A-A'A"-AA and B-B' in Plate 4). Maximum thickness of the Tertiary section in the southeastern part of the map area is on the order of 250 feet.
A summary of map unit areas for each quadrangle (Table 1) indicates significant differences in geologic makeup of each quadrangle. The Lumpkin quadrangle is dominated by the Providence Formation (42 %) with lesser amounts of the Altamaha and Ripley Formations (16 %). Also, some of the younger stratigraphic units, i.e. Tertiary Sediments and Residuum, Claiborne Group, and Tuscahoma Formation, were not recognized or were not present in the Lumpkin quadrangle. The Richland quadrangle is dominated by the Altamaha Formation (37 %) with lesser amounts ofthe Claiborne Group, Nanafalia Formation, and Providence Formation (12 to 17 %). In the Benevolence quadrangle, approximately equal amounts of the Altamaha Formation (28 %) and Claiborne Group (34 %) were mapped, and lesser amounts of the Tuscahoma and Nanafalia formations (10 to 13 %). These differences reflect a greater degree of recent erosion and dissection, as well as regional dips that expose older sediments in the Lumpkin and Richland quadrangles (Plates 1, 2 and 3). Also, several Tertiary-age unconformities appear to have removed some or all of the pre-Miocene Tertiary sediments.
Geologic cross-sections
Lithologic descriptions by Herrick (1961 and unpublished data) and anonymous logs (GGS unpublished data) plus field observations in and adjacent to the current map area provided data for the geologic cross-sections A-A'AA and B-B' (Plate 4). Herrick based his descriptions and interpretations on well cuttings collected from water supply wells drilled from the 1940s through the early 1960s. As well cuttings were usually sampled at ten-foot intervals, Herrick described most unit thicknesses based on those intervals. Because of differences in sample recovery and interpretations, lithologic descriptions as well as stratigraphic picks may vary from one well to another, and correlation between wells and between surface and well data is not necessarily optimal.
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Table 1. Percentage of quadrangle containing map unit polygons. Data is derived from Arclnfo databases created for each quadrangle's geologic map. Numbers are estimates at best because of uncertainties in the geologic mapping.

Water Quaternary Alluvium Altamaha Formation Tertiary Sediments and
Residuum Claiborne Group Tuscahoma Formation Nanafalia Formation Clayton Formation Providence Formation Ripley Formation Cusseta Formation

Benevolence 0.67% 7.71% 28.47% 0.20% 33.54% 13.33% 10.04% 3.38% 2.65% 0% 0%

Lumpkin 0.26% 8.57% 16.98% 0% 0% 0% 8.36% 4.00% 42.46% 16.25% 3.14%

Richland 0.28% 6.80% 36.83% 0.13% 12.44% 3.10% 15.70% 6.81% 16.99% 0.92% 0.0%

Accuracy of well locations is highly variable. Most of these wells were drilled for water supply purposes, and some were apparently not surveyed. Prior to the 1970's, 7.5 minute quadrangle maps were not yet available for this part of Georgia, and well locations were marked on Georgia Department of Transportation county road maps. Well locations were subsequently transferred to other maps in the Georgia Geologic Survey technical files. One GIS database was developed from wells plotted on Georgia Department of Transportation (DOT) county road maps which are located in the Georgia Geologic Survey technical files. Well locations were then plotted on digital images of each DOT county road map, and attributes were added in ArcView.
Another GIS database was developed from an earlier, unpublished digital database of GGS numbered wells that were located by latitude and longitude. A digital plot of both of those databases together show some of the same wells from each database to lie close to each other while others are either missing from one of the databases or they are relatively far apart. A comparison with data on the well log sheets as well as the probable location for a well on a topographic base map, suggests that the database that contained latitude and longitude data for the GGS wells is generally the more accurate database. Actual locations of these older wells still could be several hundred feet from the positions plotted on the accompanying geologic maps, as the precision of the latitude and longitude data does not allow a more accurate plot.
The geologic map of Reinhardt and others (1994) shows well locations with circles. Wells used by them in their mapping and cross-sections are labeled. Unlabeled wells in the vicinity of the wells described above are assumed to reference the same wells. Locations of the wells on Reinhardt's map may coincide with the locations from the DOT maps, with the unpublished digital database, or are in the vicinity of both of those locations. Well
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locations from Reinhardt's map were used to aid in the selection of which well locations from the other two databases were used for the cross-sections.
Locations of wells from the DOT maps were used when those wells were not included in the GGS digital database. Locations of all the wells in the current map area and adjacent quadrangles minus the duplicate wells are shown on the inset map in Plate 4. The numbered wells were used to construct the cross-sections. Most of the other wells shown on the inset map either did not have a lithologic log or the log was of too poor quality to be used.
STRATIGRAPHY OF THE BENEVOLENCE, LUMPKIN AND RICHLAND QUADRANGLES
Exposed stratigraphic units in the study area include the Upper Cretaceous Cusseta (Kc), Ripley (Kr) and Providence (Kp) Formations, Clayton (Tel) and Nanafalia (Tnf) Formations, Upper Paleocene Tuscahoma Formation (Ttu), Middle Eocene Claiborne Group (Tcb), the Miocene Altamaha Formation (Ta), and Quaternary Alluvium (Qal). An additional map unit, the Tertiary Sediments and Residuum unit (Tsr), is believed to consist of unidentified portions of Eocene and Oligocene stratigraphic units and their residuum. Descriptions of these units are summarized in Figure 4. Stratigraphic units identified only in well logs include the Upper Cretaceous Blufftown (Kb) and Eutaw (Ke) Formations. Because of the lack of detailed subsurface data only the Cusseta Formation and younger units are described in this report.
Upper Cretaceous Exposed Upper Cretaceous sediments in the map area include the Cusseta, Providence and Ripley Formations.
Additional formations identified in the wells in the map area include the Blufftown Formation, and the Eutaw Formation. Recent studies of the Upper Cretaceous sediments from eastern Alabama to the Flint River indicate that most of the Upper Cretaceous units contain two or more lithofacies (Rheinhardt and Gibson, 1981). These include a continental facies and a marine facies. Generally, the basal and downdip portions of these units are representative of the marine facies.
In addition, asymmetrical depositional cycles composed of a regressive and a transgressive phase are developed in the Upper Cretaceous sediments (Rheinhardt and Gibson, 1981). The regressive phases representing progradation are thicker and better developed. Progradation may be due to sedimentation rates greater than basin subsidence or to a gradual drop in sea-level. Descriptions of the lithologies and their depositional environments are discussed in Rheinhardt and Gibson (1981).
Selma Group
Cusseta Formation (Kc)
In updip areas, the Cusseta Formation consists of 170 to 235 feet of coarse, generally cross-bedded sand (Marsalis and Friddell, 1975; Rheinhardt and Gibson, 1981; Rheinhardt and others, 1984). Grain size, the amount of sand and scale of cross-bedding decrease downdip. Towards the upper contact with the Ripley Formation, thinly bedded carbonaceous clay becomes more abundant (Fig. 5). The updip portions of the Cusseta Formation represent
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deposition in a relatively stable barrier island complex. The upper sediments represent deposition in a restricted back barrier environment during a regressive sea level change (Rheinhardt and others, 1984).
Figure 5. Interbedded sandstone and brown clay of the Cusseta Formation. Louvale quadrangle. Ripley Formation (Kr)
The lower part of the Ripley Formation consists of a massive, bioturbated, fme to medium grained, micaceous, glauconitic, quartz sand. The upper part of this unit is commonly massive, fme sand to silty clay. Near the top of the Ripley Formation, grain size increases abruptly, may contain a bone and shell lag, and is well bedded (Reinhardt and others, 1994). Thickness of the Ripley Formation ranges from 135 feet updip to 250 feet downdip (Reinhardt and others, 1994). Generally, the Ripley Formation is a relatively fossiliferous unit (Fig. 7).
Older sediments were deposited in an inner shelf environment. Younger sediments were deposited in a barrier island complex (Rheinhardt and others, 1994). The top of the Ripley Formation was marked by abrupt shallowing and subaerial exposure, with development of paleosols.
Exposures of the Ripley Formation are found in the northern part of the Lumpkin quadrangle with the best exposures along US Highway 27 (Fig. 6). Recent highway construction and accompanying landscaping has degraded what was once a good fossil locality.
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Figure 6. Outcrop of Ripley Formation (Kr) underlying Providence Formation (Kp). Dashed line marks approximate

contact. Location is on US

27 north ofL' umpkln,

Figure 7. Closeup view ofhighly fossiliferous Ripley Formation in Fig. 6. 13

Providence Formation (Kp)
The Providence Formation is the youngest Upper Cretaceous unit in the current map area. Almand (1961) and Reinhardt and others (1994) mapped the Providence Formation in the Lumpkin and Richland quadrangles. Reinhardt and others (1994) describe the Providence Formation as pale yellow, cross-bedded, locally micaceous, fme to coarse sand with inter-bedded, yellowish brown to olive, massive to thinly bedded, sandy clay lenses. This unit is subdivided in cross-sections into two lithofacies. The updip lithofacies consists of cross-bedded, coarse quartz sand with locally abundant heavy minerals (Fig. 8). The heavy mineral suite consists mainly of ilmenite, zircon and rutile and locally may constitute up to one third of the sand (Rheinhardt and Gibson, 1981 ). The downdip lithofacies is a laminated to massive, highly micaceous, locally carbonaceous, silty clay and clayey fme sandstone. Both lithofacies may be burrowed or bioturbated. The updip lithofacies was divided into an upper and lower cross-bedded sand divided by a 20 inch thick sandy clay bed (Donovan, 1985). Thickness of the Providence Formation may range from 83 to 267 feet (Marsalis and Friddell, 1975; Reinhardt and others, 1994). Although the Providence Formation is relatively light colored, iron oxide staining is locally developed (Fig. 9).
The Perote Member is an olive gray to dark gray, carbonaceous, micaceous, burrowed silt and fine-grained sand. Donovan (1985) and Reinhardt and others (1994) consider the Perote Member to be the upper part of the Ripley Formation. Marsalis and Friddell (1975) described the Perote Member as the basal part of the Providence Formation. The upper member of the Providence Formation consists of variegated white to yellow to orange, micaceous, feldspathic, cross-bedded, medium- to very coarse-grained sand (Marsalis and Friddell, 1975).
Induration of the Providence Formation varies considerably from relatively hard sandstone (Fig. 8), to soft sandstone (Figs. 9, 10 and 11), to soft sand/sandstone (Fig. 12 and 13). The exposure shown in Figure 13 is in a sand pit easily dug out with power equipment. Headward erosion into the generally soft sand and sandstone of the Providence Formation has cut steep, cliff-like scarps (Figs 10 and 11). Most of this erosion is related to rapid downcutting by streams in the Chattahoochee River Basin.
The Providence Formation is locally more kaolinitic, with some kaolin lenses or layers found in the current map area. Hard kaolin (Fig. 14) was exposed during the recent highway construction on US Highway 27 south of Lumpkin.
Trace fossils consisting of clay-lined, Ophiomorpha burrows (Figs. 12 and 13) are locally abundant in crossbedded sandstone (Rheinhardt and Gibson, 1981) and are classified mainly as belonging to the Skolithos ichnofacies (Frey and Pemberton, 1984). These Skolithos ichnofacies are indicative of relatively high levels of wave or current energy, typically developed in clean, well-sorted, loose or shifting particulate substrates (Frey and Pemberton, 1984. The occurrence of this ichnofacies with large and small-scale trough cross-bedding indicates a near-shore environment such as on the foreshore and shoreface of beaches, bars and spits (Frey and Pemberton, 1984). These burrows are usually developed in soft sand and do not weather well. At one locality on US Highway 27 north of Lumpkin, these burrows are relatively well-cemented and have weathered out of the surrounding soft sand.
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Figure 8. Coarse-grained, cross-bedded sandstone of the Providence Formation. Benevolence quadrangle.
Figure 9. Iron oxide stained, massive appearing Providence Formation. Lumpkin quadrangle. 15

Figure 10. Steep escarpment caused by rapid erosion of the soft Providence Formation. Lumpkin quadrangle.
Figure 11. Steep escarpment caused by headward erosion of Providence Formation. Escarpment is less than 20 feet from road. Lumpkin quadrangle.
16

Figure 12. Ophiomorpha casts in cross-bedded Providence Formation. Lumpkin quadrangle.
Figure 13. Bed containing abundant Ophiomorpha burrows in cross-bedded sandstone of the Providence Formation. Lumpkin quadrangle.
17

Figure 14. Hard kaolin in upper part of the Providence Formation. Lumpkin quadrangle.
Figure 15. Shale and clay clast-rich breccia/conglomerate (?) at contact between the Clayton and Providence Formations. Lumpkin quadrangle.
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An wmsual shale and clay clast breccia/conglomerate was found at or near the contact of the Providence Formation and the Clayton Formation. This lithology consists of angular light gray shale and kaolin clasts (Fig. 15) in a matrix of fme- to coarse-grained sand. Several outcrops of this lithology were found along a four mile stretch of State Highway 27 west of Lumpkin. The source of the shale clasts is unknown, as this lithology was not recognized in the underlying Providence Formation. Because this lithology lies beneath the Clayton Formation, the source could not be the Clayton Formation. The origin of this breccia/conglomerate may be related to a major meteorite impact in the Gulf of Mexico at the end of the Cretaceous. Tsunamis related to the impact are believed to have deposited exotic breccia/conglomerates in similarly aged sediments around the Gulf of Mexico.
Lower Paleocene
Midway Group
Clayton Formation (Tel)
The Clayton Formation is described as being composed of yellow to buff-brown, interbedded, micaeous silty clay, calcareous sandstone, and bioclastic limestone (Reinhardt and others, 1994). The limestone is described as locally well-crystallized and well-cemented or vuggy and is composed of molluscan and bryozoan fragments.
In outcrops in the Benevolence, Lumpkin and Richland quadrangles, the Clayton Formation is represented principally by a residuum of red, buff to dark brown, white to light gray and black clay (Figs. 16 - 30). Locally, small pieces of whitish, rotten chert occur in the shale (Fig. 17) and are indicative of the former presence of carbonate. Strongly distorted bedding (Fig. 13) also suggests collapse due to dissolution of carbonates. The presence of limestone in drill core and its absence in outcrops in the mapped area suggests that weathering has removed all limestone in the present surface and near-surface environment. Irregular, small to large masses of iron-oxide (goethite ?) are commonly found in the Clayton Formation (Figs. 18, 19, 23 and 29) and were of sufficient extent and grade to have been mined in Stewart County for their iron content (Furcron, 1956).
Present mapping suggests that the Clayton Formation is discontinuous and quite variable in thickness. In crosssections (Plate 4), the Clayton Formation may range from a few feet in updip areas (Fig. 24) to as much as 40 feet in downdip areas. Extensive karstification and erosion may have been removed some or all of this unit prior to deposition of the Nanafalia Formation. Regionally, thickness of this unit may range from 10 to 165 feet (Marsalis and Friddell, 1975; Owen, 1956; Reinhardt and others, 1994), in part due to. The variability in thickness and regional thinning of the Clayton as depicted in cross-sections by Rheinhardt and others (1994) may be a better representation.
In the Chattahoochee River area, the Clayton Formation consists of three units: 1) a basal conglomerate overlain by interbedded grayish-yellow sandy, shelly limestone and calcareous sands; 2) a white to gray, dense limestone with oyster shells and other fossil debris; and 3) an upper white to gray microfossiliferous, massive limestone (Cramer and Arden, 1980; Marsalis and Friddell, 1975; Toulmin and LaMoreaux, 1963).
19

Figure 16. Clay and iron oxide boulder residuum of the Clayton Formation (Tel) underlying Altamaha Formation (Ta). Benevolence quadrangle.
Figure 17. Clay, iron oxide and chert (white fragments) of the Clayton Formation. Lumpkin quadrangle. 20

Figure 18. Clay with iron oxide mass of the Clayton Formation (Tel) underlying sandstone of the Nanafalia Formation (Tnf). Benevolence quadrangle.
Figure 19. Contorted bedding, clay and iron oxide masses in Clayton Formation. Lumpkin quadrangle. 21

Figure 20. Clayton Formation (Tel) clay underlying Nanfalia (Tnt) Formation. Lumpkin quadrangle.
Figure 21. Contorted bedding at contact between Clayton and Nanafalia Formations. Lumpkin quadrangle. 22

Figure 22. Unusual kaolinization of Clayton Formation (?) underlying iron oxide clast-rich Altamaha Formation. Lumpkin quadrangle.
Figure 23. Contorted clay and iron oxide clasts in Clayton Formation. Lumpkin quadrangle. 23

Figure 24. Thin Clayton Formation clay between underlying Providence Formation and overlying Nanafalia Formation. Lumpkin quadrangle.
Figure 25. Slightly thicker Clayton Formation with lower clay and upper iron oxide rich layer between underlying Providence Formation and overlying Altamaha Formation. Lumpkin quadrangle.
24

Figure 26. Clayton Formation clay overlying Providence Formation and underlying Altamaha Formation. Lumpkin quadrangle.
Figure 27. Closeup view of Clayton Formation - Providence Formation contact in Fig. 26. Lumpkin quadrangle.
25

Figure 28. Closeup view of Clayton Formation - Altamaha Formation contact in Fig. 26. Lumpkin
Figure 29. Iron oxide rich residuum of Clayton Formation overlying Providence Formation and underlying Nanafalia Formation. Lumpkin quadrangle.
26

Figure 30. Closeup view of Clayton - Providence Formation contact shown in Fig. 29. Lumpkin quadrangle.
Figure 31. Channel deposits of Nanafalia (Tnf) sandstone cut into Clayton Formation (Tel) clay and iron oxide residuum. Overlain by thin layer of iron oxide clast rich Altamaha Formation (Ta) conglomerate. Lumpkin quadrangle.
27

Porters Creek Formation (Tpc)
An olive-black, compact, highly glauconitic, fissile clay to silty clay that may be the Porters Creek Formation is locally present at the top of the section commonly mapped as Clayton Formation in this part of Georgia (Reinhardt and others, 1994). Thickness of this unit, where present, is 3 to 33 feet. If this clay is present in the current map area, it could not be distinguished from the clay and residuum of the Clayton Formation and is included as part of the Clayton Formation.
Upper Paleocene to Lower Eocene
Wilcox Group
Nanafalia Formation (Tnj)
In the current map area, the Upper Paleocene Nanafalia Formation is exposed mainly in the deeper stream valleys of the Chattachoochee River Basin. Although exposures of the Nanafalia Formation are generally not well developed, the best exposures were found in the western parts of the Benevolence and Richland quadrangles (Figs. 32-36). The Nanafalia Formation consist of cross-bedded, fme to very coarse, light greenish-gray to yellowish-brown to white, highly micaceous quartz sandstone and locally, kaolin (Figs. 32 and 33). The sandstone may contain abundant, rounded or subrounded kaolin clasts (Fig, 34).
Because of poor exposure, the Nanafalia- Clayton Formation contact and the Nanafalia- Tuscahoma Formation contact (Figs. 35 and 36) were seldom observed in the current map area. An exposure (Fig. 31) in the Lumpkin quadrangle shows channels of Nanafalia Formation sandstone cut into a residuum of the Clayton Formation. Significant erosion since deposition of the Nanafalia Formation has removed or cut deeply into the Nanafalia Formation in a number of exposures (Figs. 21, 22, 25, 26, 28, 31, and 32 - 36).
The Nanafalia Formation is divided into two coeval lithofacies, the Baker Hill and Nanafalia Formations (Reinhardt and others, 1994). The Baker Hill Formation is described as consisting of fme to coarse, light greenish-gray to yellowish-brown, highly micaceous quartz sand that interfmgers with light greenish-gray to black sandy clay and massive kaolin beds. Trough cross-bedding and abundant rounded to subangular clay clasts are commonly found in the sandy intervals. Commonly thick-bedded to massive clay is locally more than 33 feet thick and may contain sand or silt laminae. Scattered thick lenses of kaolin contain bauxite. The Gravel Creek Member, the marginally marine to nonmarine facies of the Nanafalia Formation (Huddlestun and others, 1974), is similar to the Baker Hill Formation of Reinhardt and others (1994).
According to Reinhardt and others (1994), the Nanafalia Formation is present only in the subsurface. This unit contains greenish-gray, micaceous, fme- to coarse-grained, glauconitic, fossiliferous, massive bedded, fossiliferous quartz sand with local clay lenses. Reinhardt and others (1994) note that the Nanafalia
28

Figure 32. Massive kaolin of the Nanafalia Formation (Tnf) overlain by Altamaha Formation (Ta) sandstone. Benevolence quadrangle.
Figure 33. Altamaha Formation (Ta) sandstone with basal conglomerate overlying cross-bedded kaolinitic sandstone and massive kaolin of the Nanafalia Formation (Tnf). Benevolence quadrangle.
29

Figure 34. Kaolin clasts in sandstone of the Nanafalia Altamaha Formation (Ta) sandstone. Lumpkin quadrangle.
Figure 35. Tuscahoma (Ttu) - Nanafalia Formation (Tnf) contact cut by the Altamaha Formation (Ta). Lower Altamaha Formation contact intersects road surface downhill to the right. Benevolence quadrangle.
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Figure 36. Tuscahoma (Ttu) - Nanafalia (Tnf) Formation contact cut by Altamaha Formation (Ta). Tuscahoma- Nanafalia contact dips to the west (right). Benevolence quadrangle.
Figure 37. West dipping contact between clay, shale, and silt of the Tuscahoma Formation (Ttu) and overlying Claiborne Group (Tcb) sandstone. Altamaha Formation cuts across both formations. Benevolence quadrangle.
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Formation may be 20 to 160 feet thick. Large, economic deposits of kaolin and bauxite are found in the Nanafalia Formation in the Andersonville, Springvale and Eufala districts. During the present project, two drill holes penetrated thick sections of kaolin at shallow depths (see appendix).
Tuscahoma Formation (Ttu)
The Upper Paleocene Tuscahoma Formation is generally poorly exposed in the map area with most exposures found in the Benevolence quadrangle. Shallow core drilling appears to indicate a relatively widespread distribution, particularly in the Benevolence quadrangle, and thickness that is not evident from the surface exposures. The Tuscahoma Formation consists of non-fossiliferous, gray, inter-laminated clay, silty clay, and fme quartzose sand (Figs. 36 and 37). Limited, exposed contacts with the overlying Claiborne Group were found in the Benevolence quadrangle (Fig. 37). Drilled thickness of the Tuscahoma Formation is on the order of 50 feet, but may be thinner or absent, due to erosion prior to the deposition of the Claiborne Group and Altamaha Formation. As the Tuscahoma Formation could not be recognized in the Lumpkin quadrangle, this may mark the northwestern extent of the Tuscahoma Formation, at least as a continuous unit.
According to Marsalis and Friddell (1975), the Tuscahoma Formation near the Chattahoochee River, consists of90 to 153 feet ofnonfossiliferous, gray, inter-laminated clay, silty clay, and fine quartzose sand. Reinhardt and others (1994) indicate the Tuscahoma is composed of 10 to 60 feet of dark greenish-gray clay and silt inter-laminated with thin, medium greenish gray, quartz sand beds. The basal bed consists of massive clayey, fme to medium-grained sand containing coarse quartz, glauconite and phosphate pebbles.
Hachetigbee Formation - Bashi Marl Member
Only one outcrop of the Bashi Marl Member was identified during the current mapping. Identification was based on several macrofossils collected and examined by Burt Carter. These fossils are discussed later in the section on biostratigraphy. Aside from those fossils, this unit could not be distinguished from lithologies of the Tuscahoma Fommation in the surface mapping or in drill hole logs. Marsalis and Friddell (1975) found the Bashi Marl to be discontinuous along the Chattahoochee River.
Reinhardt and others (1994) describe the Hatchetigbee Formation as generally less than 25 feet oflight to dark greenish-gray, dominantly massive, well-sorted, very fine- to fine-grained quartz and glauconite sand. This unit contains intervals of interbedded and inter-laminated clay, silt and very fme quartz sand.
Lower to Middle Eocene
Claiborne Group (Tcb)
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The Claiborne Group is a thick, generally sandy unit that, in the current map area, lies between the Tuscahoma Formation and the Altamaha Formation and/or the Tertiary Sediments and Residuum unit. This sandy unit appears to consist principally of the Tallahatta Formation as shown on the Geologic Map of Georgia (Georgia Geologic Survey, 1976). Sandy sediments in this stratigraphic interval which are found in this part of Georgia's Coastal Plain have normally been referred to as the Tallahatta Formation (Marsalis and Friddell, 1975). These sediments are equivalent to those sandy sediments classified as the Claiborne Group in the Americus geologic atlas (Cocker, 2003) to the east of the present map area.
Figure 38. West dipping kaolinitic sandstone with kaolin clasts of the Claiborne Group. Benevolence quadrangle.
The Claiborne Group is generally not well exposed in the current map area. Outcrops are most commonly of low relief and generally consist of light tan to buff colored, poorly indurated sand. In interfluve areas where the Claiborne Group is exposed, relief is so poorly developed that no outcrops are present. The better quality exposures are generally found along roads which descend into the stream valleys. Other good exposures may be found in recently eroded gullies, but access to these is commonly extremely difficult. As in previously mapped areas to the east (Cocker, 2003), the Claiborne Group consists generally of massive to fmely laminated, white to light tan to brick-red, locally kaolinitic, fme to coarsegrained sand and sandstone (Figs. 37 and 38). Locally, ground water has stained the sand and sandstones to various shades of yellow and red. Cross-bedding and fme-scale layering may be observed in some of the more indurated, less weathered outcrops. Thin streaks of kaolin, kaolin laminae, and kaolin clasts may also be found (Fig. 38). Thickness of the Claiborne Group ranges from 50 to 150 feet.
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Because this unit is generally poorly cemented, Claiborne Group sandstones are highly susceptible to rapid erosion. Erosion of the soft sands that constitute the deeply weathered portions of the Claiborne Group is of major concern to the farmers in the area, particularly on slopes adjacent to a major drainage. Most of the slopes adjacent to the streams have been kept in a natural, forested state to curb that type of erosion. Erosion gullying may threaten the integrity of the transportation and utility infrastructure, also.
Lisbon Formation (Tl)
The Lisbon Formation has not been observed as a distinctly identifiable unit in outcrops or in drill logs in the map area. This unit was recognized further to the east in the vicinity of the Flint River (Cocker, 2003b)
Upper Eocene
Upper Eocene sediments were not found or recognized in the present map area. Most of these sediments may have been removed by erosion prior to Miocene sedimentation. Some unidentified sediments may be included as undifferentiated sediments in the Tertiary Sediments and Residuum map unit.
Eocene to Oligocene
Tertiary Sediments and Residuum (Tsr)
In the current map area, a few exposures of undifferentiated sediments and residuum that were assigned to this unit were found in the current map area. Concentrations of chert rubble accompanied by abundant, predominantly maroon to brown to chocolate brown and less commonly white and orange, plastic or sticky clay is the best indication of this unit's presence. An unusual mixture of clay, sandstone and a shale clast conglomerate is also assigned to this unit. Chert and associated brown clays that are the most abundant part of this unit may be derived from intense, subaerial weathering of carbonate sediments.
Chert found in the map area ranges in size from gravel to cobbles and small boulders. Isolated chert clasts are commonly found associated with Altamaha Formation sediments and may be sedimentary clasts eroded from the residuum and incorporated into the Altamaha Formation during deposition of the Altamaha Formation (Cocker, 2003). The paucity of chert clasts within the Altamaha Formation within the current map area suggests that much of this residuum unit was eroded prior to Altamaha deposition and/or not much chert was present in the residuum.
Further to the east, fossils preserved within the chert-bearing residuum have been identified as Early Oligocene (Summerour, 2000) or Late Oligocene (Huddlestun and others, 1974). Stratigraphic position of
34

Figure 39. Intermixed fme-grained sandstone, shale and shale-clast conglomerate/breccia. This is classified as belonging to the Tertiary Sediments and Residuum unit (Tsr). Benevolence quadrangle.
Figure 40. Close up view of clay and shale-clast conglomerate breccia in Fig. 39. Benevolence quadrangle.
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the residuum is permissible for Early or Late Oligocene, as well as including rocks of Middle to Upper Eocene age. Early Oligocene residuum may be derived from weathering of the Oligocene Tivola or Ocala Limestone (Summerour, 2000). Late Oligocene residuum may be derived from the Suwanee Limestone.
Huddlestun and others (1974) distinguished the occurrence of chert as clasts and in situ massive chert in a similar manner to that which occurs in the current map area. Chert clasts are described as sand to gravel-size detritus, cobbles and boulders in a matrix of sand and clay. In situ chert occurs as massive bedded chert, and chert pinnacles surrounded and overlain by Neogene age sands, clays and gravels. These in situ cherts are referred to as the Flint River Formation by Pickering (1966, 1970).
Other sediments that are included in this unit consist of a mixture of brown, fme-grained sandstone, bluish gray shale, and shale-clast conglomerate/breccia. These lithologies are intermixed in the exposure shown in Figs. 39 and 40.
Thickness of the residuum unit is quite variable, because it is derived through weathering and erosion of rock units prior to Altamaha sedimentation. Average thickness is believed to be on the order of 10 to 20 feet. In other places, thickness of this residuum may be only that represented by chert rubble on the surface.
Miocene
Altamaha Formation (Ta)
Clastic sedimentary rocks of the Altamaha Formation are the youngest Tertiary rocks in the map area and are generally found at the higher elevations, particularly on the interfluve areas (Plates 1 - 3). Locally, the Altamaha Formation is present at lower elevations than its projected lower contact and has been observed in contact with the Tuscahoma, Nanafalia, Clayton and Providence Formations (Figs. 16, 21, 22, 25,26, 28, 31, 32, 33, 34, 35, 36, 37,41, 42,43,44,45,46,47,48,49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, and 62). Elevation differences in the lower Altamaha contact, as well as cutting progressively older sedimentary units to the north and west indicate a major disconformity prior to (and perhaps during) Altamaha sedimentation. Numerous exposures show the Altamaha Formation downcutting into the older sediments, also.
Thickness of the Altamaha Formation is also quite variable. Maximum thickness is probably on the order of 20 to 30 feet. The Altamaha Formation may thin to less than 10 feet in many parts of its mapped area. Although the Altamaha Formation is rather thin on the upland surfaces, its indurated sandstones have protected underlying softer sediments from more rapid erosion.
Lithologically, the Altamaha Formation consists of sandstones, clayey sandstones, and conglomerates. The dominant lithology observed in the current map area is a massive, brick-red, argillaceous, fme-grained to gritty sandstone. Small, rounded, generally black, ironstone pebbles may be very abundant to rare, but are usually present. Thin or cross-bedding is very rarely observed (Fig. 63). Weathering, iron staining and mottling probably mask the presence of more sedimentary structures and textures in the Altamaha
36

Formation. Massive, more or less mottled, clayey sandstones are usually found beneath the sandstone (Fig. 64).
A basal conglomerate is commonly present that is very useful for recognizing this unit's basal contact. Within the current map area, clast composition of the conglomerate generally consists of iron oxide, iron oxide-cemented sandstone, and ironstone pebbles (Figs. 22, 25, 28, 33, 42, 43, 45, 46, 47, 49, 50, 51, 55 and 57). Clasts of iron oxide were probably derived mainly from residuum of the Clayton Formation. Iron oxide cemented sandstone clasts were probably derived from one or more underlying sandstone units that locally have iron oxide-cemented sandstone crusts (e.g. Claiborne Group, Clayton (?) and Providence Formations. Rarely, chert or kaolin (Fig. 62) clasts may be present. The chert clasts were derived from the Tertiary Sediments and Residuum unit, and the kaolin clasts were derived from the Nanafalia Formation. Thickness of the conglomerate is generally on the order of6 inches to several feet. 16, 21, 22, 25, 26, 28, 31 -37 and 41- 62).
Altamaha Formation sandstones contain variable amounts of ironstone pebbles that generally range in size from 0.25 to 1.00 inches. Occasionally, ironstone pebbles up to 2 inches are found. Most ironstone pebbles are black and appear to be rounded to subrounded with an apparent polish. Although these pebbles were not examined by petrographic or chemical analyses, visual inspection with a hand lens suggests that these pebbles consist of clastic quartz grains cemented by a mixture of iron oxides, quartz and perhaps hardened clay. These ironstone pebbles are currently clastic in their occurrence. Generally found dispersed in a sandstone or argillaceous sandstone matrix, these ironstone pebbles are also concentrated in conglomeratic portions of the Altamaha Formation and occasionally in distinctly layered portions of the Altamaha Formation. Estimated abundance of the ironstone pebbles in the Altamaha Formation in the current map area ranges from 0 to 50% with the most abundance probably in the 5 to 10 % range. Weathering of the ironstone pebble-bearing Altamaha Formation concentrates these pebbles as a lag deposit on the present surface. Although these ironstone pebbles have been noted from this part of the stratigraphic section over much of the Upper Coastal Plain of Georgia, no source for the ironstone pebbles has been suggested.
Argillaceous sandstone is generally mottled with various shades of white, yellow and red being the most prevalent. Where present with sandier portions of the Altamaha Formation, this mottled clay-rich lithology is always beneath the sandier portion. Although relatively indurated, this clay-rich lithology is believed to be the kandic zone formed by downward mobilization of clay. The amount of clay seems to be variable throughout the current map area. Data from Long and Baldwin (1915) indicate that, despite the enrichment of clays in the subsoils (kandic zone), the rock/soil is an argillaceous sandstone based on a greater volume of sands versus silts and clays. Mottling is believed to represent oxidation and remobilization of iron by ground water during weathering. Occasionally concentration and precipitation of iron resulted in the formation of black masses which are called plinthite. These pebbles have been referred to as plinthite (Summerour, 2000); however, true plinthite is actually a soft, weathering-related segregation of iron oxide to form irregularly shaped masses (Brady and Weil, 1999). Plinthite may be found locally
37

developed as irregular-shaped masses in the lower portions of the kandic weathering zone. Size analyses and descriptions of soil and subsoil for Grady sandy loam, Greenville sandy loam,
Ruston sandy loam, and Tifton sandy loam soils in Terrell County (Long and Baldwin, 1915) suggest that these soils were derived from the Altamaha Formation (Cocker, 2001). As described in the section on soils, these four soil types have the same grain size distribution in the soil and subsoil. Subsoils show a second population of clay-size particles that reflect enrichment of clay in the subsurface. The upper soil zone corresponds to the more uniformly colored massive sandstone. The lower clayey zone corresponds to the lower mottled argillaceous sandstone.
In the present quadrangles, the Altamaha Formation disconformably overlies the Claiborne Group, the Tertiary Sediments and Residuum unit, as well as the Tuscahoma, Nanafalia, Clayton and Providence Formations. This disconforrnity can be observed at the outcrop scale where it ranges from 1 to 20 feet (Figs. 25,28,32,33,35,36,37,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60, 61, and 62), from outcrop to outcrop, and at the map scale where relief may range up to about 100 feet between outcrops (Plates 1 - 3). The disconforrnity at the base of the Altamaha Formation marks the downcutting in progressively older units to the west and north. Units mapped further to the east (Clinchfield Formation, Ocala Group, and Lisbon Formation) have been removed prior to Altamaha deposition or their lithologies are not adequately distinguishable to be separated and are included in the Tertiary Sediments and Residuum unit.
High angle jointing noted in the area of the Americus atlas (Cocker, 2000b) is generally rarely observed in the current map area. The significance of that is unknown.
Depositional environment of the Altamaha Formation is interpreted as an irregular, prograding fluvial and estuarine system developed during the Early and Middle Miocene period of lowered sea level (Huddlestun, 1988, 1993). Prior to and during the Early and Middle Miocene, Oligocene and older sediments were exposed to intensive weathering and erosion. As a result, the lower contact of the Altamaha Formation with underlying units is highly irregular. Older units exposed to the weathering and erosion may be irregular in thickness or missing.
Detailed mapping of the Altamaha Formation in South Carolina in and near the Savannah River Site (Fallaw and Price, 1992; Nystrom and Willoughby, 1982) contains similar lithologies and has similar geologic relations as those found in the present map area.
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Figure 41. Massive, brick-red sandstone of the Altamaha Formation (Ta) overlying massive, brick-red sandstone of the Claiborne Group (Tcb ?). Contact distinguished by differences in weathering between the more indurated Altamaha Formation and the softer sandstone of the lower unit.
Figure 42. Lower contact of the Altamaha Formation (Ta) with the Providence Formation (Kp) marked by thin conglomerate containing clasts of iron oxide and iron oxide cemented sandstone, as well as ironstone pebbles. Lumpkin quadrangle.
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Figure 43. Steeply dipping contact between Altamaha Formation (Ta) and underlying Providence Formation. Benevolence quadrangle.
Figure 44. Oblique view of Altamaha (Ta)- Providence (Kp) Formation contact. Benevolence quadrangle. 40

Figure 45. Unconformable contact between Altamaha (Ta) and Providence (Kp) Formations. Lumpkin quadrangle.
Figure 46. Closeup view of platy, iron oxide-cemented sandstone clasts in basal conglomerate at Altamaha (Ta)- Providence (Kp) Formation contact shown in Fig. 45.
41

Figure 47. Steep, north dipping, unconformable contact between the Altamaha (Ta) and Providence (Kp) Formations. Richland quadrangle.
Figure 48. Steep, south dipping, unconformable contact between the Altamaha (Ta) and Providence (Kp) Formations. Richland quadrangle.
42

Figure 49. Clast-rich, channel of the Altamaha Formation (Ta) cut in Providence Formation (Kp). Lumpkin quadrangle.
Figure 50. Altamaha Formation (Ta) with clast-rich basal conglomerate forming channel cut in Providence Formation (Kp). Lumpkin quadrangle.
43

of the Altarnaha Formation (Ta) overlying north dipping
Figme 52. Steep angular contact between Altarnaha Formation (Ta) sandstone and Clayton Formation (Tel) clay. Benevolence quadrangle.
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Figure 53. Uppermost "terrace" of Altamaha Formation (Ta) sandstone overlying sandstone of the Providence Formation (Kp). Richland quadrangle.
:) ..~
Figure 54. View of upper Altamaha Formation (Ta) "terrace" with angular downcutting into Providence Formation (Kp) to next "terrace". Arrows show poditions of other photos. Richland quadrangle.
45

Figure 55. Close up view of angular cross-cutting Altamaha Formation with basal conglomerate. Richland quadrangle.
Figure 56. Third lowest "terrace" of Altamaha Formation cutting Providence Formation. Richland quadrangle.
46

Figure 57. Lowest (fourth) "terrace" of Altamaha Formation that cuts Providence Formation. Basal conglomerate visible above hammer. Richland quadrangle.
Figure 58. View uphill from level of fourth "terrace" showing position of higher terraces, the vertical relief between the different terraces. Note truck for scale at top of hill. Richland quadrangle.
47

Figure 59. View Nanafalia Formation. Benevolence Formation.
Figure 60. Terraces and channels of Altamaha Formation cut into kaolinitic sediments of the Nanafalia Formation viewed downhill. Bedding in Nanafalia Formation dip downhill to the north, toward the camera. Benevolence Formation.
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Figure 61. Close up view of Altamaha Formation channel shown in Figs. 59 and 60 cutting across bedding in Nanafalia Formation. Benevolence quadrangle.
Figure 62. Close up view of erosional remnant of the Nanafalia Formation with Altamaha Formation overlying and cut across bedding in Nanafalia Formation. Kaolin clasts derived from Nanafalia Formation visible in Altamaha Formation at crest of knob. Benevolence quadrangle.
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Figure 63. Fine-scale layering near base of the Altamaha Fonnation. Lumpkin quadrangle.
Figure 64. Intensive ground water weathering of the Altarnaha Formation. Mottled upper sandstone grades down to bleached, kaolinized sandstone. Richland quadrangle.
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Quaternary
Quaternary Alluvium (Qal)
Alluvium was mapped as occupying the basal, generally flatter portions of creek valleys in the map area. Alluvium was mapped as extending up the smaller tributaries where a stream occupied the valley and the valley could be recognized as a valley on the topographic map. Except for minor exposures along stream banks, no outcrops were observed. The few exposures suggest that the alluvium in the current map area is similar to that described by Hetrick (1990) and Summerour (1999, 2000). Alluvium is described as consisting of variably micaceous, poorly-sorted sand, clayey sand, and clayey silt, with a minor amount of quartz and local chert gravel, and variable amounts of organic matter. The generally larger expanses of swampy areas in the present map area suggest a greater portion of organic matter may be present than in areas further to the east (Summerour, 1999, 2000). Thickness of alluvium is variable and is probably greater in the major creek valleys (Choctahatchee, Lanahassee, Bear, Kinchafoonee and Muckalee Creeks).
Alluvial terraces that were formed during downcutting of the creeks may be present but are not recognizable on the topographic maps of these quadrangles or in the field mapping. The soft, easily erodable nature of the sediments in the Claiborne Group, Tuscahoma, Nanafalia, Clayton, Ripley and Providence Formations would tend not to preserve a recognizable terrace.
51

Alteration of primary sedimentary textures
Most of the outcrops of Coastal Plain clastic rocks observed during the mapping of the past several years do not display primary sedimentary textures. This is particularly apparent in those rocks that are dominantly red or reddish brown in color. Alteration of clastic rocks, particularly through groundwater movement and deposition of iron oxides that stain the rocks various shades of red, yellow and brown, appears to obliterate the appearance of primary sedimentary textures. In general, fresh outcrops of the Providence Formation exhibit primary textures such as cross-bedding and burrows.
Correlation of STATEMAP map units with nearby 1:100000 scale maps and the 1:500000 scale Geologic Map of Georgia
Differences between the Americus 1:100,000 scale geologic map (Reinhardt and others, 1994) and the Benevolence, Lumpkin and Richland quadrangles (Fig. 2, Plates 1 and 2) may be due, in part, to differences in stratigraphic definitions, map units delineated, and the presence of lithologies previously unrecognized and unmapped by Reinhardt and others (1994). Table 2 shows the STATEMAP stratigraphic terminology compared with the terminology of Reinhardt and others (1994).
The principal difference between the present mapping and that of Reinhardt and others (1994) is that the stratigraphy above the Lower Eocene Hatchetigbee Formation, except for alluvium, was not subdivided in the Americus 30' x 60' quadrangle map (Reinhardt and others, 1994). All younger sediments are included in the "Tallahatta Formation and younger Paleogene deposits, undivided (Oligocene?-lower Eocene)" (Tta) unit by Reinhardt and others (1994). This suggests that Reinhardt and others (1994) did not recognize Miocene age sediments or did not have the time to delineate the younger stratigraphy. This map unit (Tta) is equivalent to the three Middle Eocene through Miocene stratigraphic units in the current study area (Fig. 4, Plates 1 though 4). Comparisons were made by plotting a scanned version of the earlier map with the current mapping.
On the 1:500,000 scale Geologic Map of Georgia (Georgia Geologic Survey, 1976) the map units which lie within the current map area are the Cusseta (Kc), Ripley (Kr), Providence (Kp), Clayton (Pel), Nanafalia (Pnf), and Tuscahoma Formations (Ptu), Claiborne undifferentiated (Ec), and Eocene and Oligocene residuum undifferentiated (Eo-M). In the current map area, because of difficulties in distinguishing these units in the field, several of these formations (Clayton and Nanafalia formations plus the Porters Creek Clay) are combined as an undifferentiated unit (Pen). A plot of the Digital Geologic Map of Georgia (Cocker, 1999a) relative to the currently mapped geology of the Benevolence, Lumpkin and Richland quadrangles illustrates a relatively good agreement of the two sets of maps. The principal differences lie in the mapping of Quaternary alluvium in stream valleys and the mapping of the Altamaha Formation (Ta) and Tertiary Sediments and Residuum (Tsr) generally in the stratigraphic position of the Eocene and Oligocene residuum undifferentiated (Eo-Ns) on the Digital Geologic Map of Georgia (Cocker,
52

1999a). Spatial differences are related to the reconnaissance scale mapping that produced the Geologic Map of Georgia (Georgia Geologic Survey, 1976), stretching the usable scale of the Digital Geologic Map of Georgia (Cocker, 1999a) to that of the 7.5 minute quadrangles, and to errors created during production of the Digital Geologic Map of Georgia (Cocker, 1999a).

TABLE 2. Comparison of STATEMAP stratigraphic terminology with that of the Americus geologic map of Reinhardt and others (1994).

STATEMAP Project stratigraphic terminology (current map area) (Ta) Miocene Altamaha Formation (Tsr) Tertiary Sediments and Residuum (Tcb) Middle Eocene Claiborne Group- Tallahatta Formation/Lisbon Formation (Ttu) Upper Paleocene Tuscahoma Formation (Tn) Upper Paleocene Nanafalia Formation
(Tel) Lower Paleocene Clayton Formation (Kp) Upper Cretaceous Providence Formation (Kr) Upper Cretaceous Ripley Formation (Kc) Upper Cretaceous Cusseta Formation

Americus 1:100,000 geologic map of Reinhardt and others (1994) (Tta) Tertiary Tallahatta Formation and ymmger Paleogene deposits, undivided (Oligocene? -lower Eocene).
(Ttu) Upper Paleocene Tuscahoma Formation (Tn) Upper Paleocene Baker Hill and Nanafalia Formations (Tc) Lower Paleocene Clayton Formation (Kp) Upper Cretaceous Providence Formation (Kr) Upper Cretaceous Ripley Formation (Kc) Upper Cretaceous Cusseta Formation

BIOSTRATIGRAPHY
Outcrops of Tertiary age sediments in the present map area are generally nonfossiliferous. Chert residuum within the Tertiary Sediments and Residuum unit and chert clasts in the Miocene Altamaha Formation are locally fossiliferous in the present map area. In occurrences of this chert further to the east, fossils were identified as Late Eocene, Early Oligocene, and Late Oligocene (Huddlestun and others, 1974; Summerour, 2000).
Trace fossils, in the form of Ophiomorpha burrows, are found within sandstone of the Providence Formation and appear concentrated within a particular horizon. Burrows are generally lined with kaolin and appear to have kaolin cementing sand within the burrows. Those burrows depicted in Figs. 12 and 13 are on the order of 1 to 1.5 inches in diameter and have a thicker kaolin lining. Most burrows are soft, but one outcrop of soft sand contains relatively indurated burrows that have survived weathering (Fig. 13). Overall length of individual burrows may be on the order of several feet and appear to branch. Burrows are
53

generally straight to slightly curved. These burrows may have been built by a clam or crab. This type of trace fossil within shallow or nearshore marine sediments is classified as belonging to the Skolithos ichnofacies of trace fossils (Frey and Pemberton, 1984). These trace fossils are useful as a paleoenvironmental indicators but are not unique to a particular time interval.
The Ripley Formation is a relatively highly fossiliferous stratigraphic unit. A classic fossil locality used to be well exposed adjacent to US Highway 27 north of Lumpkin and about 1/.i mile south of Frog Bottom Creek. Recent highway construction and landscaping had a detrimental effect on that locality. Descriptions of the fossils from that locality and other Ripley Formation exposures are included in Almand (1961) and Eargle (1955). Table 3 lists the macrofossils noted by Almand (1961). The Ripley Formation also contains a number of foraminifera microfossils (Almand, 1961).

Table 3. Macrofossils identified from the Ripley Formation (Almand, 1961).

Genus

Species

Mollusca

Ostrea tecticosta Gabb

Ostrea subspatula Forbes

Ostrea plumosa Morton

Gryphaea

Gryphaea vesicularis (Lamarck)

Exogyra

Exogyra costata Say

Exogyra cancellata Stephenson

Anomia

Anomia argentaria Morton

Paranomia

Placuna scabra

Paranomia scabra (Morton)

Gastrochaena Gastrochaena ripleyana Stephenson

Several specimens of Venericardia bashiplata and one specimen of Macrocallista sylvaerupis were found at one roadcut in the southern part of the Benevolence quadrangle. These fossils were identified by Burt Carter (personnel communication, 2004) and are both known to be from the Bashai Marl Member of the Hachetigbee Formation.

54

STRUCTURAL GEOLOGY
Structural features observed in the map area include diapirs, synclines, bedding tilted opposite to the regional trend, and possibly a sedimentary breccia.
Diapirs are developed along the Nanafalia- Clayton contact and are only observed in the northwestern part of the Lumpkin quadrangle, on the south side of Highway 39c, between Greater New Hope Church and Shady Grove Church. These structures appear to be the result of soft sediment deformation perhaps due to overloading of Nanafalia sandstone on soft, wet, Clayton Formation clay (Figs. 66, 67 and 68). A thin layer of iron oxide-cemented sandstone, one to several inches thick, generally forms an outline of the clay in the adjacent sandstone. Some portions of the iron oxide-cemented sandstone appear to extend through the Nanafalia sandstone above the contact with the clay. Cementation of the sandstone occurred subsequent to the deformation. Structures briefly described by Cramer (1960), Almand (1961) and Marsalis and Friddell (1975) appear to be of the same roadcut or set ofroadcuts.
Several, low amplitude, synclinal folds (Figs. 69, 70 and 71) are located in or near the town of Lumpkin. One of these folds, on the western side of subdivision south of Highway 27, affects a kaolinitic Providence Formation sandstone. The fold and sandstone are truncated by the unconformity at the base of the Altamaha Formation (Fig. 71). Another syncline is found just west of Ushers Millpond on Highway 39c. Thin-bedded clay of the Clayton Formation and upper sandstones of the Providence Formation are affected by this fold (Fig. 69). Based on these outcrops, folding occurred subsequent to the Clayton Formation (Lower Paleocene) and prior to the Altamaha Formation (Miocene). A third syncline exposed on the eastern side of the center of Lumpkin appears to have affected both the Altamaha Formation and underlying Providence Formation (Fig. 70) suggesting that folding occurred subsequently to deposition of the Altamaha Formation.
Because regional dips are to the southeast, bedding that was found to dip to the north and to the west (Figs. 36, 37, 38, 51, 59 and 60), particularly along the western side of the Benevolence quadrangle, is anomalous and indicates more and probably larger-scale folding has occurred. Because of limited exposures, the entire fold structure or all of the affected beds on the opposite hinges of the folds could not be identified.
55

Figure 66. Diapir of Clayton Fonnation (Tel) clay cut into Nanafalia Fonnation (Tnt) sandstone. Diapir outlined by iron oxide-cemented sandstone. Lumpkin quadrangle.
Figure 67. Two diapirs of Clayton Fonnation (Tel) clay cut into Nanafalia Formation (Tnt) sandstone. Diapir outlined by iron oxide-cemented sandstone. Lumpkin quadrangle.
56

Figure 68. Diapir of Clayton Formation (Tel) clay cut into Nanafalia Formation (Tnf) sandstone. Diapir outlined by iron oxide-cemented sandstone. Lumpkin quadrangle.
Figure 69. Synclinal fold of Clayton Formation (Tel) clay overlying Providence Formation (Kp) sandstone. Lumpkin Formation.
57

Figure 70. Synclinal fold of Altamaha Formation (Ta) sandstone overlying Providence Formation (Kp) sandstone. Lumpkin
Figure 71. Synclinal fold in Providence Formation (Kp) sandstone overlain by unfolded Altamaha Formation (Ta). Lumpkin quadrangle.
58

ECONOMIC GEOLOGY

Two principal types of ore deposits occur within the present map area. High-grade iron ore was mined from the Clayton Formation beginning about 1954. Kaolin deposits occur in the Paleocene Nanafalia Formation in a number of places, but these have not been mined to date.
The principal mining occurred in the easternmost portion of the Lumpkin SW quadrangle by the Dunbar and Layton Mining Company. Remnants of this mining operation are still visible, although the area is mostly covered by high weeds and forest. The Southern Mining Corporation produced ore from a property about 1 mile northeast of Lumpkin (Furcron, 1956). Analyses of ore samples from several locations in Stewart County ranged from 52.72 to 58.73 %metallic iron, 0.01 to 0.96 %metallic manganese, 2.9 to 10.88 % silica, and 0.007 to 0.32% phosphorous pentoxide. The ore was strip mined, crushed, washed and shipped by rail to Birmingham, Alabama for the manufacture of steel.
The iron ore was found in two zones, 3 to 6 feet apart, near the base of the Clayton Formation. Origin of the limonite and goethite ore is unknown. Suggestions include: 1) replacement of calcium carbonate by siderite with subsequent weathering of the siderite to form limonite and goethite, and 2) in situ replacement of calcium carbonate by the iron oxides (Kirkpatrick, 1959).
Several kaolin occurrences of potentially economic significance were found during the present field work. Two are in roadcuts (Fig. 32) in the Nanafalia Formation on the western side of the Benevolence quadrangle. The other kaolin occurrence was discovered near the western side of the Richland quadrangle during the drilling program. Two kaolin occurrences, the Sidney Baldwin and the Dr. Tom Pritchett properties (Smith, 1929) are found in the vicinity of the roadcuts noted here in the western part of the Benevolence quadrangle.

Table 4. Kaolin analyses (R. Hammack, pers. Comm., 7/21/04)

Sample number Al203 Si02 Fe203 Ti02 CaO MgO Na20 K20 P205

662-158 46.6 50.0 1.06 2.07 0.06 0.08 0.06 0.08 0.10

GGS#4041 45.9 51.3 0.67 1.91 0.06 0.09 0.05 0.07 0.10

GGS#4040 46.1 51.0 0.56 2.04 0.06 0.09 0.05 0.07 0.10

HYDROGEOLOGY
Aquifers present in the current map area include the Claiborne, Clayton, and Cretaceous aquifers. Depths and aquifer thicknesses are summarized in Table 5. Data were obtained principally from the cross-sections depicted in Plate 4.
59

Sedimentary units that contain the regionally important Upper Floridan aquifer were not found or recognized in the present mapping or in the lithologic logs of previously drilled wells. Ocala Group limestones that are present to the east and southeast of the present study area contain the Upper Floridan aquifer (Cocker, 2003b, Summerour, 2000).
Claiborne Aquifer
The Claiborne aquifer is composed of Claiborne Group sediments. Claiborne Group sediments increase in thickness to the south and southeast and have been partially eroded where they are exposed in the current map area. Erosion prior to Altamaha deposition has also reduced the thickness of the Claiborne Group as illustrated in Plate 4. Depth and thickness of the Claiborne aquifer shown in Table 5 are derived from map data (Plates 1 through 3) and well data plotted in Plate 4. Recharge occurs principally through exposures of the Claiborne Group sediments or through Quaternary alluvium.
The Claiborne Group sediments are relatively porous and permeable with soils rapidly drained of moisture during drought conditions. Stock or irrigation ponds dug into the upper portions of the Claiborne Group do not hold water, whereas those dug near the base of the Claiborne Group are more likely to retain water. Permeability measurements of surface exposures of the Claiborne sediments are reported by Beck (1982). Permeability decreased in the more argillaceous portions of the Claiborne sediments and in outcrops which were armored by secondary clays.
This aquifer is locally confmed by overlying clay-rich zones in the Altamaha Formation or clay-rich residuum in the Tertiary Sediments and Residuum map unit. Throughout the study area, downward movement of surface and groundwater is inhibited by the relatively impermeable shale and clay of the underlying Tuscahoma Formation. Extensive swampy areas in Muckalee Creek and its stream network are underlain by the Tuscahoma Formation.
Principal users of the Claiborne aquifer in the current map area are wells for agricultural irrigation (McFadden and Perriello, 1983). The Claiborne aquifer provides much of the base flow to streams which are in the Flint River Basin in the eastern side of the Benevolence and Richland quadrangles. Base flow of the streams could be adversely affected by withdrawals and prolonged drought conditions (McFadden and Perriello, 1983). Water quality, transmissivity and potentiometric surface data for the Claiborne aquifer through 1982 are available in McFadden and Perriello (1983). Water quality, potentiometric surface and water use data through 1986 are provided by Long (1989).
Clayton Aquifer
The Clayton aquifer is confmed principally to permeable limestones within the middle limestone unit of the Clayton Formation. Relatively impermeable silt and clay in the upper part of the Clayton Formation and overlying Nanafalia Formation and in the lower part of the Clayton Formation and upper part of the underlying Providence Sand are the principal confming lithologies of the Clayton aquifer (McFadden and Perriello, 1983).
60

Within the current map area, the Clayton Formation is represented mainly by a relatively impermeable, clay residuum. Surface recharge into the Clayton Formation is probably minimal because of its relatively surface impermeability, its generally thin to discontinuous surface exposure, and its commonly steeply inclined surface exposure. More significant recharge of the Clayton aquifer may occur further down dip through overlying, more permeable sediments. Depth and thickness of the Clayton aquifer shown in Table 5 are derived from well data plotted in Plate 4.
The Clayton aquifer probably provides minimal water for municipal, agricultural and industrial use in the current map area because of the relatively impermeable clays that make up the major part of this unit in this area, and relatively little recharge is expected. Water quality, transmissivity and potentiometric surface data for the Clayton aquifer through 1982 are available in McFadden and Perriello (1983). Water quality, potentiometric surface and water use data through 1986 are provided by Long (1989).
Cretaceous Aquifers
In the map area, aquifers below the Clayton aquifer include the Eutaw, Blufftown, Cusseta, and Providence aquifers. Aquifers below the Providence aquifer are not important ground-water sources in the current map area because of greater expenses for well construction and problems of water quality (McFadden and Perriello, 1983).
A significant portion of the current map area consists of exposed Providence Formation. Because much of the Providence Formation appears to be permeable sand, recharge of this aquifer would be significant. Down dip subsurface data for the Providence Formation, which forms the Providence aquifer, is inadequate to provide a reasonable picture of this aquifer in the current map area. Some ground water communication may exist further down dip between the Providence and Clayton aquifers (McFadden and Perriello, 1983).

TABLE 5.

Aquifer characteristics in the study area.

Aquifer Claiborne Clayton Providence

Rock Units
Claiborne Group (including Lisbon Formation where present) Clayton Formation
Providence Formation

Depth 0 to 50 feet 0 to 210 feet 0 to 260 feet

Thickness 0 to 70 feet 0 to 40 feet 130 feet?

61

EVIDENCE FOR PAST GROUNDWATER MOVEMENT
Evidence of past ground water activity is apparent in iron oxide cemented and iron stained sediments, as well as mottled sediments. Several episodes of groundwater movement were observed in at least one exposure. Selective iron oxide cementation of cross-bedded sandstone as well as iron oxide-staining is shown in Figure 72.

"" ..

~

.

Figure 72. Iron oxide cemented, cross-bedded, Providence Formation sandstone. Lumpkin quadrangle.

In Figure 73, earlier iron oxide plus silica (?) - cement in the Providence Formation sandstone formed an impermeable layer that prevented subsequent, downward ground water movement. Currently, ground water emerges from above the top of that impermeable layer and flows over the edge. Sand above the impermeable layer is stained by iron oxide and is relatively indurated, whereas sand below the impermeable layer is soft and easily eroded.
Evidence in the form of distinct mottled zones indicates several episodes of groundwater movement (Fig. 74). Two earlier mottled zones separated by approximately four feet of non-mottled sandstone probably represent two prolonged periods of relatively stable groundwater tables during which the mottling was developed. These sediments were subsequently tilted so that these mottled zones dip presently to the north.

62

Figure 73. Iron oxide stained and cemented sandstone above more indurated iron oxide cemented sandstone layer in Providence Formation. Soft, white, cross-bedded sandstone lies below the more indurated layer. Lumpkin quadrangle.
Figure 74. Two tilted, temporally separate mottled zones developed in Altamaha Formation sandstone. Tilting is to the north. Benevolence quadrangle.
63

GEOLOGIC HAZARDS Several important geologic hazards that were observed during the present mapping involve soft, commonly unconsolidated sands, soft sandstone, and locally soft clays. Soft sands are found mainly in the Cusseta, Ripley, and Providence formations and in the Claiborne Group. The soft clays belong principally to the Tuscahoma and Clayton formations. Principal hazards in areas underlain by soft sand include rapid erosion of farmland, roadways, and undercutting and collapse of stream and road banks. Most farmlands are developed on soils overlying the Altarnaha Formation. More indurated portions of the Altarnaha Formation prevent rapid erosion of those soils. Rapid erosion of sandier soils on hillsides underlain by the Claiborne Group and the Providence Formation may initiate gullying. Headward erosion may encroach into the overlying Altamaha Formation and the soils developed on top of that unit. Generally, as the slope becomes steeper, erosion and gullying becomes more rapid. Many of the hillsides adjacent to stream valleys have been left to grow as forested land to help prevent erosion. Roadways that run down to creek and river valleys and drainage ditches adjacent to the roadways serve to channel runoff and are particularly susceptible to erosion where they are underlain by the Providence Formation or Claiborne Group sands. Where the roadways are paved, the drainage ditches are commonly cemented. In other places, miscellaneous material such as recycled concrete blocks, tires, kitchen appliances, etc. have been placed in those ditches to slow the runoff and resulting erosion. At several places adjacent to paved roads, drainage from the roadways has caused or exacerbated severe erosion (Figs. 75 and 76). Vertical erosion is as much as 15 to 25 feet. Such erosion may cause catastrophic collapse of the adjacent road. The cliff-like erosional escarpment caused by headward erosion of the Providence Formation may also be extremely hazardous to hunters that may come suddenly upon a 15 to over 30 foot dropoff (Figs. 10 and 11 ). Erosion and undercutting of stream banks may be especially hazardous where structures or infrastructures are involved. Erosion and undercutting of stream banks where gas, water and sewer pipelines are exposed may cause these pipelines to collapse and rupture. Buildings that are placed on the edges of stream banks are also subject to erosion and undercutting of the stream banks. Areas that have been built up and paved over are more susceptible to increased runoff, erosion and stream bank undercutting. Soft clay of the Clayton and Ripley formations are a geologic hazard especially when the clay is wet. The most frequently encountered hazard is on unpaved roads where slippery conditions may send a vehicle off course into a ditch, tree or another vehicle. Rutted, dried out clay is also hazardous, as the ruts may also send a vehicle out of control or a vehicle may high center on a rut. Logging trucks commonly use roads in this area, and their heavy loads cause abnormally deep ruts. Local government road graders are frequently needed to smooth out the ruts.
64

Figure 75. Erosional downcutting into soft Claiborne Group sandstone resulting from runoff from highway culvert. Richland quadrangle.
65

Fjgure 76. Deep pit eroded in soft Claiborne Group sandstone by runoff from hlgbway culvert. Richland quadrangle.
66

SUMMARY
Geologic mapping of the Benevolence, Lumpkin and Richland quadrangles (Plates 1 to 3) show the interpreted distribution of Cretaceous, Tertiary and Quaternary sediments. Cross-sections (Plate 4) show the interpreted subsurface geology based on a few widely scattered drill holes and the mapped surface geology. Exposed stratigraphic units in these quadrangles consist of the Upper Cretaceous Cusseta, Ripley and Providence Formations, Lower Paleocene Clayton Formations, Upper Paleocene Nanafalia and Tuscahoma Formations, Middle Eocene Claiborne Group, residuum of possibly Eocene and Oligocene sediments (Tertiary Sediments and Residuum), and the Miocene Altamaha Formation. Quaternary alluvium is found in stream valleys.
Episodes of exposure, weathering, and erosion followed the deposition of: 1) Upper Cretaceous Providence Formation, 2) Lower Paleocene Clayton Formation, 3) Upper Paleocene Nanafalia Formation, 4) Upper Paleocene Tuscahoma Formation, 5) Middle Eocene Claiborne Group sediments; 2) Upper Eocene Ocala Group sediments; and 3) Oligocene sediments. An additional episode of exposure, weathering, and erosion during deposition of the Nanafalia Formation recognized in the Andersonville bauxite district (Cocker, 2003a, b), may also have occurred, but cannot be verified because of poor exposure. The complex depositional, weathering, and erosional history of the Tertiary sediments pose a number of mapping and stratigraphic identification difficulties, particularly the placement of the lower contact of the Altamaha Formation between mapped control points.
Numerous exposed contacts between the Altamaha Formation and older formations indicate a complex erosional surface with significant relief was present at the time of Altamaha deposition.
Two drill intercepts of near-surface kaolin and several outcrops of kaolin in the upper parts of the Nanafalia Formation suggest further exploratory work is warranted. Because these kaolin occurrences occur in the same relatively up dip position as the Andersonville and Eufala bauxite districts, development of bauxite mineralization could be anticipated.
Structural features observed in the map area include diapirs, synclines, bedding tilted opposite to the regional trend, and possibly a sedimentary breccia. The diapirs are soft sediment deformation features concentrated along the Nanafalia - Clayton contact. These may be related to sediment loading during deposition of the Nanafalia Formation. At least one period of tectonic deformation is suggested by a syncline developed in the Providence Formation that has not affected the overlying Altarnaha Formation. Another syncline developed in the Providence and overlying Altamaha Formation suggests a second, later period of deformation. The occurrence of a sedimentary breccia at the contact between the Providence and Clayton formations is unusual. This could be related to a major meteorite impact at the close ofthe Cretaceous.
Recharge of the Claiborne aquifer occurs through the Claiborne Group sediments in the Benevolence and Richland quadrangles. Permeability of the Claiborne Group sediments is adversely influenced by an increase in clay content. Recharge zones for the aquifers below the Claiborne are not exposed in the map area. The mapped distribution of the chert and clay residuum found between the Altamaha Formation and the Claiborne Group marks the theoretical limit of the Upper Floridan aquifer. Recharge of the Upper Floridan aquifer in the map area is probably minimal because of the clays in the residuum.
67

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Beck, B. F., 1982, The permeability of the Tallahatta aquifer in its outcrop area, Georgia: Georgia Geologic Survey Open File Report 82-3, 19 pp..
Brady, N.C. and Weil, R.R., 1999, The Nature and Properties of Soils, Prentice Hall, Upper Saddle River, N.J., 881 pp.
Bybell, L. M. and Gibson, T. G., 1982, The Eocene Tallahatta Formation of Alabama and Georgia: its lithostratigraphy, biostratigraphy, and bearing on the age of the Claibornian Stage: United States Geological Survey Professional Paper 1615, 20 pp.
Clarke, J. S., Faye, R. E., and Brooks, R., 1983, Hydrogeology of the Providence aquifer of southwest Georgia: Georgia Geologic Survey Hydrologic Atlas 11, 5 pl.
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Cocker, M.D., 2000c, Digital geologic map of the Bronwood quadrangle, Georgia: Georgia Geologic Survey Documentation Report 00-27, 21 pp., plus one CD-ROM
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Cocker, M.D., 2001, Geologic atlas of the Bottsford, Dawson, Parrott and Shellman 7.5 minute quadrangles, Ga.: Georgia Geologic Survey Open-File Report 01-1, pp., 5 pl.
Cocker, M.D., 2002, Geologic atlas of the Americus, Lake Collins, Plains, and Preston, Georgia 7.5 minute
68

Quadrangles, Georgia: Georgia Geologic Survey Open File Report 02-1, 74 pp., 5 plates. (scale@ 1:24000).
Cocker, M.D., 2003a, Geologic atlas of the Andersonville, Methvins and Pennington 7.5 minute quadrangles, Georgia: Georgia Geologic Survey Open File Report 03-1, 83 pp., 4 plates. (scale@ 1:24000).
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Cocker, M.D. and Costello, J.O., 2003, Geology of the Americus Area, Georgia: Georgia Geological Society Guidebooks, Volume 23, Number 1, 64 pp.
Cramer, H. R. and Arden, D. D., 1980, Subsurface Cretaceous and Paleocene geology of the Coastal Plain of Georgia: Georgia Geologic Survey Open File Report 80-8, 184 pp.
Eargle, D. H., 1955, Stratigraphy of the outcropping Cretaceous rocks of Georgia: United States Geological Survey Bulletin 1014, 101 pp.
Fallaw, W.C. and Price, V., 1992, Outline of stratigraphy at the Savannah River Site: in Fallaw, W.C. and Price, V., eds., Geological Investigations of the Central Savannah River Area, South Carolina and Georgia: Carolina Geological Society Field Trip Guidebook, p. CGS-92-11-1 - CGS-92-11-25.
Frey, R.W. and Pemberton, S.G., 1984, Trace fossil facies models: in Walker, R.G., ed., Facies Models, Second Edition, Geoscience Canada, Reprint Series 1: Geological Association of Canada, p. 189-207.
Fritz, W. J., ed., 1989, Excursions in Georgia Geology: Georgia Geological Society Guidebooks, vol. 9, #1, 264 pp.
Furcron, A. S., 1956, Iron ores of the Clayton Formation in Stewart and Quitman Counties, Georgia: Georgia Mineral Newsletter, vol. IX, p. 116-123.
Georgia Geologic Survey, 1976, Geologic map of Georgia: Georgia Geological Survey, Atlanta, Georgia, 1:500,000 scale.
Gibson, T. G., 1982, Paleocene to Middle Eocene depositional cycles in eastern Alabama and western Georgia Coastal Plain: in Arden, D. D., Beck, B. F., and Morrow, E., eds., Proceedings: Second Symposium on the Geology of the Southern Coastal Plain: Georgia Geologic Survey Information Circular 53, p. 53-63.
Gohn, G. S., Bybell, L. M., Christopher, R. A., Owens, J.P., and Smith, C. C., 1982, A stratigraphic framework for Cretaceous and Paleocene margins along the South Carolina and Georgia Coastal sediments: in Arden, D. D., Beck, B. F., and Morrow, E., eds., Proceedings: Second Symposium on the Geology of the Southern Coastal Plain: Georgia Geologic Survey Information Circular 53, p. 64-74.
Gorday, L. L., Lineback, J. A., Long, A. F., and McLemore, W. H., 1997, A digital model approach to water-supply management of the Clairborne, Clayton, and Providence aquifers in southwestern Georgia: Georgia Geologic Survey Bulletin 118; 31 pp., 2 supplements.
Herrick, S. M., 1961, Well logs of the Coastal Plain of Georgia: Georgia Geologic Survey Bulletin 70, 462 pp.
Herrick, S.M. and Vorhis, R. C., 1963, Subsurface geology of the Georgia Coastal Plain: Georgia Geologic Survey Information Circular 25, 78 pp.
Hetrick, J. H., 1990, Geologic atlas of the Fort Valley area: Georgia Geologic Survey Geologic Atlas 7, 2 pl.
Hetrick, J. H., 1992, A geologic atlas of the Wrens-Augusta area: Georgia Geologic Survey Geologic Atlas 8, 3 pl.
Hetrick, J. H., 1996, Geologic atlas of the Butler area: Georgia Geologic Survey Geologic Atlas 9, 8 pp., 1 pl.
69

Hetrick, J. H. and Friddell, M. S., 1990, A geologic atlas of the central Georgia Kaolin District: Georgia Geologic Survey Geologic Atlas 6, 4 pl.
Huddlestun, P. F., 1985, An examination of the Altamaha Formation near Oak Park, Emanuel County, Georgia: Georgia Geological Society Guidebooks Volume 5, Number 1, p. 1-19.
Huddestun, P. F., 1988, A revision of the lithostratigraphic units of the Coastal Plain of Georgia: The Miocene through Holocene: Georgia Geologic Survey Bulletin 104, 162 pp.
Huddlestun, P. F., 1992a, The Paleogene of the northeastern Gulf of Mexico Coastal Plain: in Zullo, V. A., Harris, W. B., Price, V., eds., Savannah River Region: Transition Between the Gulf and Atlantic Coastal Plains: Proceedings of the Second Bald Head Island Conference on Coastal Plains Geology, University of North Carolina at Wilmington and U. S. DOE, p. 23-24.
Huddlestun, P., 1992b, Upper Claibornian coastal marine sands of eastern Georgia and the Savannah River Area: in Fallaw, W.C. and Price, V., eds., Geological Investigations of the Central Savannah River Area, South Carolina and Georgia: Carolina Geological Society Field Trip Guidebook, p. CGS-92-XII-1- CGS-92-XII-6.
Huddlestun, P. F., 1993, A revision of the lithostratigraphic units of the Coastal Plain of Georgia: The Oligocene: Georgia Geologic Survey Bulletin 105, 152 pp.
Huddlestun, P. F. and Hetrick, J. H., 1979, The stratigraphy of the Barnwell Group of Georgia: Georgia Geological Society, 14th field trip guidebook: Georgia Geologic Survey Guidebook 18, 89 pp.
Huddlestun, P. F. and Hetrick, J. H., 1985, Upper Eocene stratigraphy of central and eastern Georgia: Georgia Geologic Survey Bulletin 95, 78 pp.
Huddlestun, P. F. and Hetrick, J. H., 1991, The stratigraphic framework of the Fort Valley Plateau and the central Georgia kaolin district: Guidebook for the 26th Annual Field Trip, Georgia Geological Society, vol. 11, no. 1, 119 pp.
Huddlestun, P. F., Marsalis, W. E., and Pickering, S. M., Jr., 1974, Tertiary stratigraphy of the central Georgia Coastal Plain: Georgia Geologic Survey Guidebook 12, Part 2, 35 pp.
Johnston, R. H. and Miller, J. A., 1988, Region 24, Southeastern United States: in Back, W., Rosenhein, J. S., and Seaber, P. R., eds., Hydrogeology, Geological Society of America, The Geology of North America, Hydrogeology, vol. 0-2, p. 229-236.
Kirkpatrick, S.R., 1959, The geology of a portion of Stewart County, Georgia: MS Thesis, Emory University, 79 pp.
Kirkpatrick, S.R., 1963, Geology of the Lumpkin SW quadrangle, Stewart County, Georgia: The Compass, v. 41, no. 1, p. 40-51.
Long, A. F., 1989, Hydrogeology of the Clayton and Claiborne aquifer systems: Georgia Geologic Survey Hydrologic Atlas 19, 6 pl.
Luckett, M.A., 1979, Cretaceous and Lower Tertiary stratigraphy along the Flint River, Georgia: unpublished M. S. Thesis, University of Georgia, 51 pp.
Marsalis, W. E. and Friddell, M. S., 1975, A guide to selected Upper Cretaceous and Lower Tertiary outcrops in the lower Chattahoochee River valley of Georgia: Georgia Geologic Survey Guidebook 15, 87 pp.
McFadden, S. S. and Perriello, P. D., 1983, Hydrogeology of the Clayton and Clairborne aquifers in southwestern Georgia: Georgia Geologic Survey Information Circular 55, 59 pp.
Mitchell, G. D., 1981, Hydrogeologic data of the Dougherty Plain and adjacent areas, southwest Georgia: Georgia
70

Geologic Survey Information Circular 58, 124 pp., 3 pl. Nystrom, Jr., P.G. and Willoughby, R.H., 1982, Cretaceous, Tertiary, and Pleistocene (?) stratigraphy of Hollow
Creek and Graniteville quadrangles, Aiken County, South Carolina :in Nystrom, Jr., P.G. and Willoughby, R.H., eds., Geological investigations related to the stratigraphy in the Kaolin Mining District, Aiken County, South Carolina: Carolina Geological Society Field Trip Guidebook, p. 80-109. Owen, V., 1956, Stratigraphy and lithology of southern Webster County, Georgia: unpublished M.S. thesis, Emory University, 82 pp., plus map, cross-section and stratigraphic column. Reinhardt, J., 1982, Lithofacies and depositional cycles in Upper Cretaceous rocks, central Georgia to eastern Alabama; in Arden, D. D., Beck, B. F., and Morrow, E., eds., Proceedings: Second Symposium on the Geology ofthe Southern Coastal Plain: Georgia Geologic Survey Information Circular 53, p. 89-96. Reinhardt, J., 1986, Stratigraphy and sedimentology of continental, nearshore, and marine Cretaceous sediments of the eastern Gulf Coastal Plain: Society of Economic Paleontologists and Mineralogists Field Trip #3, AAPG Annual Meeting, Atlanta, Georgia: Georgia Geologic Survey, 99 pp. Reinhardt, J. and Gibson, T. G., 1981, Upper Cretaceous and lower Tertiary geology of the Chattahoochee River valley, western Georgia and eastern Alabama: Guidebook for the 16th Annual Field Trip, Georgia Geological Society, 88 pp. Reinhardt, J., Schindler, J. S., and Gibson, T. G., 1994, Geologic map of the Americus 30' X 60' quadrangle, Georgia and Alabama: United States Geological Survey Miscellaneous Investigations Series Map 1-2174, 1 pl., 1 pamphlet. Smith, R. W., 1929, Sedimentary kaolins of the Coastal Plain of Georgia: Georgia Geologic Survey Bulletin 44,482 pp. Toulmin, L. D. and LaMoreaux, P. E., 1963, Stratigraphy along the Chattahoochee River, connecting link between Atlantic and Gulf Coastal Plains: American Association of Petroleum Geologists Bulletin, volume 47, #3, p. 385-404. Zapp, A. D. and Clark, L. D., 1965, Bauxite in areas adjacent to and between the Springvale and Andersonville Districts Georgia: United States Geological Survey Bulletin 1199-H, p. Hl- HlO,l pl.
71

APPENDIX Drill Hole Logs for the STATEMAP Program (February, 2004 through April, 2004)
72

Drill Hole Logs for the STATEMAP Program (February, 2004 through April, 2004)

Drill Hole: Drilled: Location: Total depth: Elevation:

GGS #4039 February, 2004 Richland Quadrangle 45 feet 615 feet (approximate)

Depth

Description

0-1'

no recovery

1-10'

massive, brick-red, weakly argillaceous, gritty, fme-grained sandstone

10- 10.5'

massive, rusty red, argillaceous, fme-grained sandstone

10.5- 12.5' massive, rusty brown, micaceous clay; 2" fragment of iron oxide at 11'

12.5 -13'

massive, brick-red, fme-grained sandstone

13- 14.5'

massive, rusty brown, clay and clayey silt

14.5- 22.5' massive, rusty to rusty brown and light gray, micaceous siltstone

22.5- 26.5' massive, brown and reddish brown clay

26.5- 32'

massive, light gray to white, fine-grained sandstone

32- 45'

massive, white, various shades of red and yellowish brown, medium- to coarse-grained, weakly micaceous sand

Formations

0-13'

Altamaha Formation

13- 26.5'

Clayton Formation

26.5- 45.0'

Providence Formation

73

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0- 1.0' 1.0- 7.5' 7.5 - 15.0' 15.0- 18.5'
18.5- 20.0' 20.0- 35.0' 35.0- 41.5' 41.5- 44.0' 44.0 -45.3' 45.3- 47.5' 47.5- 50.0'

GGS #4040 February, 2004 Richland Quadrangle 50 feet 61 0 feet (approximate)
Description
no recovery
massive, brick-red, very argillaceous, fme-grained sandstone
massive, brick-red, argillaceous, gritty, fme-grained sandstone
massive, reddish brown to rusty red, weakly argillaceous, medium- to coarse-grained, soft sandstone
massive, white to rusty brown, kaolinitic, medium-grained sandstone
massive, mottled, gray, red and brown kaolin
massive, white kaolin
massive, mottled, reddish brown and light gray to white kaolin
massive, white, kaolinitic, fme-grained sandstone
massive, white, micaceous kaolin
massive, white, micaceous, fme-grained sandstone

Formations 0- 15' 15- 50'

Altamaha Formation Nanafalia Formation

74

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0 -13.5' 13.5 - 32.0'
32.0-45.0'
Formations 0 -13.5' 13.5 -45.0'

GGS #4041 February, 2004 Richland Quadrangle 45 feet 600 feet (approximate)
Description
massive, brick-red, argillaceous, fme-grained sandstone, 5 - 7.5' common iron stone pebbles
massive, light gray to white with brown streaks, kaolin; streaks less prominent from 15 to 20'; essentially clean from 24 to 32'; </= 10% quartz
massive, white to very light gray, micaceous, fme-grained sandstone/sand; weakly rusty in upper 2 feet
Altamaha Formation
Nanafalia Formation

75

Drill Hole: Drilled: Location: Total depth: Elevation:
Depth 0- 1.0' 1.0- 5.5' 5.5 -22.5' 22.5- 33.5' 33.5- 42.5'
Formations 0-5.5' 5.5 -42.5'

GGS #4042 February, 2004 Richland Quadrangle 42.5 feet 515 feet (approximate) Description no recovery massive, brick-red, grading down to rusty red, argillaceous, fme-grained sandstone massive, rusty red grading to light brown to brownish white, silt to clayey silt thin-bedded, tan, black, pinkish red, crimson and rusty toward base (bottom 2.5'), clay massive, purple, rusty red and brown, fme- to medium-grained, weakly argillaceous sand; water at contact between sand and clay
Altamaha Formation ? Tuscahoma Formation

76

Drill Hole: Drilled: Location: Total depth: Elevation:
Depth 0-2' 2.0- 13.5'
13.5- 18.5' 18.5- 21.0' 21.0- 27.5' 27.5- 29.5' 29.5- 37.0' 37.0-40.0' 40.0- 50.0'

GGS #4043 February, 2004 Richland Quadrangle 50 feet 535 feet (approximate)
Description
no recovery
massive, brick-red, argillaceous, gritty, fme-grained sandstone; fme- to coarse-grained @ 12.5 13.5'; minor ironstone pebbles
massive, mottled rusty brown and brick-red, micaceous, argillaceous, fme-grained sandstone
massive, mottled rusty brown and brick-red, micaceous, sandy clay
thinly layered, crimson red, light gray, and white, micaceous clay
massive, blood red, argillaceous, fme-grained sandstone
thinly layered, purple and rusty red, argillaceous, fme-grained sandstone
massive, purpe and rusty red, argillaceous, fme-grained sandstone
massive, rusty green, micaceous claystone

Formations 0- 13.5' 13.5- 18.5' 18.5- 50.0'

Altamaha Formation Claiborne Group ? Tuscahoma Formation

77

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0- 1.0' 1.0 - 2.5' 2.5- 12.0'
12.0- 13.0'
13.0 -15.0' 15.0- 22.3' 22.3- 24.0' 24.0- 31.0'
31.0-42.5'

GGS #4044 February, 2004 Richland Quadrangle 42.5 feet 485 feet (approximate)
Description
no recovery
massive, brick-red to orange red, argillaceous, fme-grained sandstone
massive, mottled in upper 4 feet to white in lower part, argillaceous, fme-grained sandstone; strongly bleached in lower part/ kaolinitic; iron oxide cemented sandstone pebble at 4.5'
massive, brown, fine-grained sandstone; iron oxide-cemented sandstone crust at 13 ', </= 1", at contact with clay
massive, rusty brown clay
massive to thinly layered, light gray, brown and rusty red, micaceous clay
massive, brown to rusty brown, sandy mud
massive, purple with rusty patches, argillaceous, micaceous, fme-grained sandstone; thinly layered in lower foot
massive, green, micaceous claystone cut by red and black iron oxide lined/filled fractures

Formations 0 -13.0' 13.0 -42.5'

Claiborne Group ? Tuscahoma Formation?

78

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-5.5'
5.5 -12.5' 12.5- 14.0' 14.0- 18.5' 18.5- 22.5' 22.5- 26.0' 26.0- 29.5' 29.5' 29.5- 30.0' Formations 0-5.5' 5.5- 14.0' 14.0- 30.0'

GGS#4045 February,2004 Richland Quadrangle 30 feet 465 feet (approximate) Description massive, brick-red, argillaceous, gritty, fme-grained sandstone, common ironstone pebbles; mottled in lower foot massive to thinly layered, mottled rusty brown and white, weakly micaceous siltstone and clay massive, brick-red, micaceous, very fme-grained sandstone massive variegated, brown, red and light brown, micaceous siltstone thinly layered, maroon to red and white, micaceous siltstone similar to above 18.5- 22.5', but very wet and muddy massive to thinly layered, brick-red, argillaceous/muddy, very fine-grained sandstone to siltstone black and dark red, iron oxide-cemented sandstone crust massive, green and red soft clay
Altamaha Formation Claiborne Group Tuscahoma Formation

79

Drill Hole: Drilled: Location: Total depth: Elevation:
Depth
0-13.0'
13.0- 15.5'
15.5- 17.5'

GGS#4046 February, 2004 Benevolence Quadrangle 17.5 feet 445 feet (approximate)
Description
massive, brick-red to reddish brown, argillaceous, fme- to medium-grained sandstone; common ironstone pebbles
similar to above, generally lighter in color and broken up
massive, coarse-grained, light brown to rusty brown sandstone; muddy at top and wet

Formations 0- 15.5' 15.5- 17.5'

Altamaha Formation Claiborne Group

80

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-2.5' 2.5 -12.5'
12.5- 18.0' 18.0- 21.0' 21.0- 24.0' 24.0- 25.6' 25.6- 27.5' 27.5- 30.0' 30.0- 45.5' 45.5- 50.0' Formations 0-2.5' 2.5- 12.5' 12.5- 50.0'

GGS #4047 February, 2004 Benevolence Quadrangle 50 feet 510 feet (approximate) Description massive, brick-red to red, argillaceous, fme-grained sandstone; minor iron oxide pebbles massive, brick-red to rusty brown to white, fme-grained sandstone; soft; red from 2.5- 5' and 7.5 - 8.5' finely layered, rusty brown, green, dark gray and cream, clay and silt fmely layered to massive, crimson red siltstone finely layered, crimson red, light red and cream, micaceous siltstone and clay massive, reddish brown, fine-grained sandstone fmely layered to massive, rusty brown and light gray, micaceous clay and siltstone massive, light to medium gray, quartz-bearing clay; coarse quartz scattered throughout clay thinly layered, dark gray, micaceous clay; coarse quartz similar to above massive to fmely layered, purplish and light to medium greenish gray, argillaceous sandstone
Altamaha Formation Claiborne Group Tuscahoma Formation

81

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0- 1.0' 1.0 - 12.5'
12.5- 15.5' 15.5- 19.0' 19.0- 26.0' 26.0 -27.5' 27.5- 28.0' 28.0- 36.5'
36.5 -40.0' 40.0- 50.0'

GGS #4048 March, 2004 Benevolence Quadrangle 50 feet 565 feet (approximate)
Description
no recovery
massive, brick-red, argillaceous, fme-grained sandstone; weakly mottled in lower 2.5 '; uncommon ironstone pebbles
massive, mottled, dark gray, white and brown, clay
massive, variegated, dark gray, rusty brown and brown, argillaceous, fme-grained sandstone
massive, locally banded, purple, crimson red and white, clay
massive, locally banded, brown, white and cream, clay
massive, rusty brown, brown and gray, fme-grained sandstone
banded, various shades of brown, micaceous clay; small offset in bands at 35'; patchy black iron oxide
massive, brown to rusty brown, fme-grained sand; minor black, iron oxide cement
massive, pale orange, fme-grained sand

Formations 0 -12.5' 12.5- 36.5' 36.5- 50.0'

Altamaha Formation Tertiary Sediments and Residuum Claiborne Group

82

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-0.5' 0.5 -2.5' 2.5- 11.5' 11.5- 40'
Formations 0-11.5' 11.5- 40.0'

GGS#4049 March, 2004 Benevolence Quadrangle 40 feet 560 feet (approximate)
Description
no recovery
brown siltstone
mottled, rusty brown and cream to white, weakly micaceous, siltstone and clay
massive, white, brick-red and dark gray, locally micaceous, fme-grained sandstone; iron oxide cement at 12.5', 23' and 25'; coarse-grained from 32.5- 37.5'; two brown, sticky clay layers in interval from 37.5- 38'
Tertiary Sediments and Residuum
Claiborne Group

83

Drill Hole: Drilled: Location: Total depth: Elevation:
Depth 0-4.0' 4.0-6.5' 6.5' 6.5- 7.0' 7.0- 8.5' 8.5- 10.0' 10.0- 12.5' 12.5- 14.0' 14.0- 30.0' 30.0- 31.0' 31.0- 35.0'

GGS #4050 March, 2004 Benevolence Quadrangle 35 feet 495 feet (approximate)
Description massive, brick-red, fme-grained sandstone massive, brick-red, argillaceous, fme- to coarse-grained sandstone; occasional quartz pebbles
1" clay/kaolin
massive, reddish brown, fme-grained sandstone 1" clay/kaolin
thinly bedded, gray clay and reddish-brown, fme-grained sandstone
massive, green and rusty brown, sticky clay; scattered small quartz grains
massive, mottled green with rusty red and brown splotches, clay
massive to faintly thin bedded, black siltstone and clay
massive, brown with light gray specs, wet, argillaceous sandstone
massive to faintly thin bedded, black siltstone and clay

Formations 0-10.0' 10.0- 35.0'

Claiborne Group Tuscahoma Formation

84

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0 -1.5' 1.5- 3.0' 3.0 -7.5' 7.5 -8.0' 8.0-10.0' 10.0- 11.5' 11.5- 12.5' 12.5 -15.0' 15.0- 19.0' 19.0- 30.0'
30.0-40.0'

GGS#4051 March, 2004 Benevolence Quadrangle 40 feet 487 feet (elevation on quadrangle map)
Description
no recovery
massive, brown, fme-grained sandstone
massive, brick-red and rusty red, weakly micaceous, fme-grained sandstone
massive, light rusty brown, kaolinitic sandstone
massive, rusty brown, coarse-grained sandstone; thin, 0.25", layer of iron oxide at 9.8'
massive, rusty tan and green clay
massive, mottled, dark rusty brown and green clay
fmely layered, rusty tan and green clay with trace, small iron oxide pebbles
massive, green clay with iron-enriched fracture? at 18.5' massive, green, micaceous siltstone; contains scattered quartz grains (</= 0.25"), frequently encrusted with iron oxide
massive, rusty brown and gray, micaceous, glauconitic? siltstone

Formations 0- 10.0' 10.0- 40.0'

Claiborne Group Tuscahoma Formation

85

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0 -15.0'
15.0- 36.0'
36.0 -40.0'

GGS #4052 March, 2004 Benevolence Quadrangle 40 feet 470 feet (approximate)
Description
thinly layered, generally alternating red and cream to light tan, micaceous, argillaceous, siltstone and clay; mainly ligb.t brown from 14 to 15'; average dip to coarse axis= 20; uncommon quartz pebbles in upper 2.5'
thinly layered; layers not as distinct as above; rusty brown, light green and light greenish brown, micaceous clay with minor siltstone component; silty clay; bedding dip gradually changes to 1510-5
massive, brown and light greenish brown, strongly glauconitic, sandy siltstone

Formations 0-40.0'

Tuscahorna Formation

86

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-4.0'
4.0- 18.0'
18.0- 25.0'
25.0- 26.5'
26.5- 30.5' 30.5- 31.2' 31.2-32.75' 32.75- 40.0'
Formations 0-8.0' 8.0- 26.5' 26.5- 31.2' 31.2 -40.0'

GGS #4053 March, 2004 Benevolence Quadrangle 40 feet 660 feet (approximate)
Description
massive, brick-red, argillaceous, fme-grained sandstone, minor ironstone pebbles; contact uncertain- based on upper end of recognizable muscovite
massive, brick-red, micaceous, argillaceous, fine- to coarse-grained sandstone; becomes increasingly micaceous and coarser-grained toward 18'; especially from 11 to 18'
massive, tan to white to light brown, micaceous, kaolinitic (especially from 23 to 25'), medium- to coarse-grained sandstone; kaolinite mainly as clasts ?
massive, rusty brown, micaceous, fme-grained sandstone with masses of black to dark gray, iron oxide and silica cemented sandstone
massive, brown to rusty brown clay
massive, crimson red clay
massive, mottled, brown to rusty brown to white, sandy clay
massive, orangish, weakly micaceous, fine-grained sandstone; 33.5 to 34' dark gray to black, weakly iron-oxide and silica cemented sandstone
Altamaha Formation
Nanafalia Formation
Clayton Formation
Providence Formation

87

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-2.0'
2.0-15.0'
15.0- 27.5'
Formations 0- 27.5'

GGS#4054 April, 2004 Benevolence Quadrangle 27.5 feet 540 feet (approximate)
Description
massive, brick-red to reddish brown, argillaceous, weakly micaceous, fme-grained sandstone; 2 iron-oxide cemented layers at 2'
massive, white to light tan, streaked/mottled from 2 to 7.5', kaolinitic, micaceous, fme-grained sandstone
massive, white to light tan, kaolinitic, micaceous, medium- to coarse-grained sandstone; rusty brown from 23.5 to 24.5' and from 26.5 to 27'
Providence Formation

88

Drill Hole: Drilled: Location: Total depth: Elevation: Depth 0-4.0' 4.0- 10.5'
10.5- 13.5' 13.5 -18.0' 18.0- 20.0'
20.0- 21.0' 21.0- 21.6' Formations 0-4.0' 4.0- 21.6'

GGS #4055 April, 2004 Lumpkin Quadrangle 21.6 feet 560 feet (approximate)
Description massive, mottled, brown, micaceous clay and minor siltstone; irregular contact
massive, white to tan to orange, micaceous, very fme-grained, sugary sand; 2 inches of light gray kaolin at 6.5'; irregular, scattered, light gray kaolin masses; rare quartz pebbles
apparent thinly layered to massive, light gray to reddish-brown, micaceous silt and clay
massive, purple to red, kaolinitic, medium- to coarse-grained sandstone
massive, variegated, red to purplish gray, micaceous, kaolinitic silt/clay; wet; one large quartz pebble
massive, light brown, micaceous, wet clay
2 inches very soft, light brown, micaceous clay; 4 inches harder, micaceous clay
Clayton Formation
Providence Formation

89

Drill Hole: Drilled: Location: Total depth: Elevation:
Depth 0-6.5' 6.5- 8.5' 8.5 -9.5' 9.5- 12.25' 12.25- 16.0' 16.0- 18.5' 18.5- 21.0' 21.0- 26.0' 26.0- 26.2' 26.2 -26.5' 26.5- 27.0' 27.0- 30.0' 30.0- 31.0' 31.0- 35.0'

GGS #4056 April, 2004 Lumpkin Quadrangle 35 feet 535 feet (elevation on quadrangle map) Description massive, brick-red to mottled, argillaceous, gritty, fme- to coarse-grained sandstone massive, mottled, brick-red and white, kaolinitic siltstone ? massive, brick-red, coarse-grained sandstone
massive, light rusty-brown, micaceous siltstone massive, mottled, brick-red and creamy white clay (kaolin)
massive to thinly layered, creamy white, brick-red and reddish brown, micaceous clay
massive, rusty brown clay and minor siltstone
massive, brown, fine-grained, sugary sandstone
thin-bedded, rusty brown siltstone massive, brown, fme-grained, sugary sandstone
massive, brown clay; small, soft, black iron oxide segregations
massive, brown to rusty brown, very fme-grained sandstone grading down to siltstone
massive to faintly thin layered, reddish brown clay
massive, light brown grading down to rusty brown, fme-grained, sugary sandstone; thin iron oxide at upper contact; contact approximately 20 to ca

Formations 0- 35.0'

Nanafalia Formation

90

UNITED STATES DEPART:vlENT OF THE INT ERIOR
GEOLOGICAL S:JRVEY

UNITED STATES
DEPARTME NT OF n--11~; ARMY CORPS OP ENGINEERS

Georgia Geologic Mapping Program Open-File Report 04-1
Plate 1
LUMPKIN QUADRANGLE
GEORGIA - STEWART CO. 7.5 MTNU T FS SEf<IES \TOPOGR ft PHiC)
'>E.'~ Ll.'M P'< IN 1!'i' Q U..CJR.'l.i\O!..Ii:

Location Map of the Lumpkin 7.5 Minute quadrangle

M<rpped by the Army Map SerJice
Published for civil use by the Geological Survey
Cont.-o l by USGS. NOSINGAA, USC, and Goorg1;;1 Gco ctct1c Survey
lopngrnphy by phot.Qgramrnelrrc rnetllod'J troo aerial ~rapns. taken l 947. Pll!lr,imeby t'l':Vltecl by phc!QU.Jmmetric n:ethods. from aerial ph:nograph5 token 1953 Field check~d 1955
Polycomc projact~an 10,DCD- rOQ.t. grill t iCk! bast!d Ort Galll!lil t::.:Jotd1nate ~y:ohm . west zcr~e 1 000-nJ ~er UmvttrMI Tranwer-.,e Mercator grid (ic.ks.,
ZltnP. 16. ~hnw11 m blue
192: 7 Nart.h American D.1b.Jm To pitt~ \'Jn the Pre<;h<.:te:i North America n Oalliill 19-83 rrtolh! IM prOJectlcm Jmes 11 rMtef!: soutn and
7 met~rs 'tle!>1 <IS sr,cr...-n ll'J' das~ed corne1 ticlui

UThl G~IO J.1ID l'l:84 WGHET,L; NORTH m: nrr.:~mm " ' Cl:rlfHI Clf S'"IUT
RewrsroM s~n rn purplf, unO W()[)d(and cDmpiled by the ~~~~~. s~rv:Y in coo~rat~n-~rth State of Georgi~ ageocics

COt; T;;LR INrERVA.L 10 FEE1
NATIONAl. f.i[ODEl"IC Vfl{liCAl DAT U~ OF 1929
T ' IIS M A.f' COM PLI ES W ITH N "'.TIO '~/o. L IJI A' I'CCU R!I.CY ::. TAN D AfW ~
FOR SA L[ SV iJ S. GE.OlO C:iiCA L S URV EY. RE'RTOI", VIRGINIA 22(192
II rOLili:.f{ DO.St'Rit:I NC TOI'Cl.I<J\f'IIIC MAl'S AND S YMB.fl i SIS M Ai t..AI:I LE ON REQUfSI

- \ ,
ll G~l>/..l:>\
/, ,, i \
0 L"JJ~ 'H L1ll L:..;c;. flf;N

'll

P.OAD CLJ\SSIF !CATION

HM',yduly_____ --~~

-.-. M11dimn dutr __---~-

....
C..;

u

s.

RVi.ltfo

,.,
\._) State R0u+e

LUMPKIN, GA.
lili."~ W li!Pl{I N IS (IUIII>AANCl l.E
32084-A7- TF-02-1
19!55 PHillTOREVI!i=:f.:f) l~Ail.

Geologic Map of the Lumpkin Quadrangle, Georgia

Explanation
Detailt:d descriptions uf rock units included in t~xt of Open File Report 04-1. B.-ief descriptinn of rock un its pruvid~d on Plate 4.
Map Units
C J \.Vater C J Qal - Quartemary Alluvium C J Ta - MioccneA ltamaha Formation C J Tsr - Tertiary Sediments and Re.-;iduum C J Tcb Middle Eocene Clairborne Group C J Ttu- Upper Paleocene Tuscahoma Formation C J Tnf - Upper Paleocene Nanafalia Formation
C J Tel - Lower Paleocene Clayton Formatwn
C J Kp- Upper Cretaceous Providence Fotmali on C J Kr-Uppa Cretaceous RipleyFormation
C J Kc - Upper Cretaceous Cusseta Fmmation I/ VICross SectiOn
[ 2 g Contact (located approXImately)
I/ VIFold Trace (located approxi mately) Arrows indicated dtrectwn cf bedding dips
[ i l l Well or core hole locatiOn
Geology by Mark D . Cocker Drgrtlzed and d rg1tally complied by Mark D. Cocker Map prOJection , Albers Come Equal Area NAD27 September, 2004 Supported by the U.S. Geologtcal Survey, Natwnal Cooperative Geologrc Mapping Program, under assistance Award Agreement #03HQAG0083

UNITED STATES DEPARTMENT OF THE I NTEf~ IOR
GEOLOGICAL SURVEY

STATE OF GEORGIA
DEPARTMENT OF' MINES, MINII-IG, AND GEOLOGY DJVJSION OP CONSER\'ATJON

Georgia Geologic Mapping Program Open-File Report 04-1

RICHLAND QUADRANGLE
GEORGiA
'1.5 MINl!Tii SERIES (TOPOGRAPHIC)

Plate 2

I
I
I'I
I
.I 'I
' '

Location Map of the Richland 7. 5 Minute quadrangle

1; j.
-~. , \
i '

Fit'l(' r('d da'>h~ l ~e~ intJ,.:;ot"' :>~els(;ted le n:::r. aud f1elr\ l uw ~ .vtH~Ie
genere lly .t'.it:~"" nr; aenal pl10togr;epf)s H-11s IJ\fQrmat,on ;!.. unL'J<.:ciu:d
M31J OllOtoltlSp!'ct.W 1981
No miljor cul~re or drainage ,::l"an;;e~ ob~f~cd

JH~ 6R D AN I) "< 72 "o.G I ~'OTI:; t<CR'irl D~ t' l ,, .<fiDN ,11 <::~~HR Of' S " Of.l

1mS MAP COMPLI[S Wlllt ~ATIONAL MAl' AGCUR~C:Y STAhDAA[}S FOR SAlE BY U. S. GEOlOGICAL SURVEY
DENVER, COLORADO 80225, OR RESTON , VlRGIIIIIA 22092 A FOlDER DESQJIS/NG TOPOGRA?ttrC MAPS 11' ND S'rlotBOLS IS !WAil..ABl E ON REOUEST

U w m).!mved ma<l
C) lnter5tale Rou te f] u S Ro utec () SWle Route
RICHLAND, GA.
N32CO- W8437 5/i" 5
1972 PHOTOINSPECTEO 1981
AMS ~Q-tS rr s w -~,mu:;o;; ve~

Geologic Map of the Richland Quadrangle, Georgia

Explanation
Delailed descriptions of rock unit.;; included in text of Open File Repo r t 04-1. Brief description of rock units provided on Plate 4.
Map Units
c=J W<1ter c=J Qal- Quatternmy Alluv mm c=J Ta - M iocene A ltamaba Format10n c=J 1'sr - ]ertiary Sediments and Residuum c=J Tcb- Middle Eocene Clairbome Group and Upper P aleocene Tuscohom a Formation c=J Ttu - Upper Paleocene Tuscahoma Fom1atmn c=J Tnf- Upper Paleocene Nanafaha Formation
fcl - Lo~A-er Paleocene Clayton Fonnat 10n
c=J Kp - Upper Cretaceous Providence Form::ttion c=J Kr - Upper Cretaceous Ripley Formation
I,/'\./j Cross SectiOn
~ Contac t (located approxnnately)
~ Well or core hole location
Geology by Mark D. Cocker Digitized and digitally c ompi led by Mark D Cocker Map project ion, Albers Come Eq ua l A reaNAD27 September, 2004 Supported by the U.S Geological Survey, Natrona! Coopemt1ve GeologiC Mappmg Pro gram, under asststance Award Agreement #03HQAG0083

UNITED STATES DEPARTMENT OF THE INTERIOR
GEOLOGICAL SURVEY

STATE OF GEORGIA
DEPARTM ENT OF' MTNES, MINING, AND GEOLOOY DIVISION

Georgia Geologic Mapping Program Open-File Report 04-1

BENEVOLENCE QU~DRANGLE
GEORGIA
7.5 MINUTE SERISS (TOPOGRAPHIC)

Plate 3

.,
Location Map of the Benevolence 7.5 Mmute quadrangle

, ,._'. 'I~'' .'
': f
...,:-- -i, ls,._,.

I.

~.

1

r; :

<

I

THIS MAP COiw1PUES WtTH NAYI(lN!Il 1111\P iU;t.;URACY STAI\IIAfWS
fOR SAL BY U. S G0LOGICJ\l. SURVEY DENVER, COLORADO 80225, OFI RESTON, VIRGINIA 2m92
fl. fot.))fR DESCAJBING TOPOGAIIPHle MAPS AWEJ. S'YMDOlS tS 1\VJ\JIABLE ON fli=:OlJE~T

BENEVOLENCE:, GA
N3152 5-WB4}7 5J? 5
197<:

Geologic Map of the Benevolence Quadrangle, Georgia

Explanation
Detailed descriptions of rock units included in text of Open File Report 04-1
Map Units ~ Water ~ Qal- Quartemat)' Alluvmm ~ Ta- M10cene Altamaha Fonnation ~ Tsr - Terttary Sedtments and Res iduum
~ Tcb - Middle Eocene Claubome Group
c=J Ttu- Upper Paleocene Tuscahoma Fotmalton c=J Tnf - Uppct Paleocene Nana(31iaFormatwn
c.=J Tel- Lower Paleocene Clayton Formation
c=J Kp- Upper Cretaceous Pro\-tdence Fonnation 1./\J'I Cross Sectwn
l 6 a Contact (located approxtmately)
~ Well or core hole lonltion
Geology by Mark D. Cocket DJgJltzed and digitally comp1led by Mat k D. Cocker Map proJeCtiOn, Albers Come Equal Area NAD27 September, 2004 Supported by tb~ lJ.S. Geological Surve:y, Nation<il Cooperative Geologtc Mappmg Program, under assistance Award Agreement #03HQAG0083