THE GEOLOGY OF THE NORTHEASTERN PORTION OF THE DAHLONEGA GOLD BELT Jerry M. German Georgia Department of Natural Resources Environmental Protection Division Georgia Geologic Survey ,, THE GEOLOGY OF THE NORTHEASTERN PORTION OF THE DAHLONEGA GOLD BELT Jerry M. German . .( Georgia Department of Natural Resources J. Leonard Ledbetter, Commissioner Environmental Protection Division Harold F. Reheis, Assistant Director G~orgia Geologic Survey William H~ Mclemore, State Geologist Atlanta 1985 Reprinted 1990 BULLETIN 100 Contents Page Abstract ..... ~ ................................... .............................................................. . 1 1ntroduction ; ...................................................... , ......................... , .. -.. 1 Previous Investigations d_, ...... , , .. , . ..... -: .. ': ,._. ........ ::., .. ,., ,., . , .. ; .. .1 Stratigraphy ................................................................................................3 Introduction ..........................................................................._............. 3 Pumpkinvine Creek Formation .......................... : . ........................................ ... 3 Pumpkinvine Creek Formation Undifferentiated ......... .- ............................... ... 3 Barlow Gneiss Member ......................................-........................................ 4 Canton Formation .................................................... ~ ............................. 7 Proctor Creek Member ...................... , .. .- ...................................................7 Palmer Creek Member ........................................._.........................................9 Chestatee Member .......................... .- ...... :... , ............................. .- .... , ... 9 Helen Member ................. ; ............... , ;;-~;:: .............. , ..................... , ...... 10 univeter Formation .................. .' ...... ..-.... .... .' .......... : ... .- ................... : ........... 11 Intrusive Rocks ................................................ ~ ..... _............ -.... : . ....... 11 Rocks Northwest and Southeast of the Study Area .................:..... ; ....'.......... , ................. 12 Structure ... .' ..... : ............... .- .................................. ~ .. :--:..~.~-.:.:... ~............... : ... ;: .. -... 12 Metamorphism ..:.....,: .. i..................................................... ~ ............................14 Economic Geology .i., .:.- i;. -...:..... :.......................... 1.......................... . -~.; : ..... 17 Introduction ................:........................................................... .- ..... 17 Mining History and Methods .............................. ; ......................................... 17 Occurrence and Genesis of Gold ...................... , ... ............. : .................................. 17 Massive Sulfide Deposits .... , .. , ....................-...... ........................................ 22 Unique lithologies of Possible Economic Significance . .........:................." ..........................:...... 22 Iron Forma.tion ........ , ............. ' .. i, ,: ~;- ~ ', . , ; ) -. 22 Tourmalinite ......... : ........ ,; .. . .' .. , , , ,: ...... , . : .. .- ..................... 22 Pyritic S<;:hist ...... ,' ... , ........ , ... , .. .- .... .. ; .:; ................... 23 Massive :Kyanite ......... .- .. :. : .... ; .. ,., ............... .-; ............. ~ .: ... ; .......................... 23 Geologi~ Mod~I . : .......: .......... , .. : .. ,. .- .... , : ....... , ............... 23 Summary ..... ~ ............ ........... , ... ,, ......... , ................... 26 References ... , , .:.................... , :, .......... : .. , ........ -.................. 27 ; Appendix , . , .......... ; ....... : .......... ... , : ... , ........................... 29 Plate 1 ................. , ... ~ .......... : ..... -.....; ..... : ..j~ , : ~ in pocket Plate 2 .............. , ....... .... , .... ...... ; .~,........................... in pocket ., . ' \ \ iii . .. ~. . ... Figure List of Figures 1. Geographic extent of the Dahlonega gold belt showing study area .................................... . 2. Diagrammatic stratigraphic section of lithologic units of the study area ................................. . 3. Photograph of "chicken track" texture of an amphibolite from the Pumpkinvine Creek Formation ........ . 4. Photograph of radiating hornblende crystals in the coarsely porphyroblasric facies of the Pumpkinvine Creek Formation .................................... .................................................. . 5. Type locality of the Barlow Gneiss Member ......................................................... . 6. Photograph of a sample of the Barlow Gneiss Member showing flattened porphyroblasts ................ . 7. Photomicrograph of polycrystalline plagioclase porphyroblast (Barlow Gneiss Member) embedded in a fine-grained matrix .............................................................................. . 8. Type locality of the Proctor Creek Member ......................................................... . 9. Photograph of banded nature of the coarsely porphyroblastic facies of the Proctor Creek Member ....... . 10. Type locality of the Palmer Creek Member ......................................................... . 11. Type locality of the Chestatee Member ............................................................ . 12. Type locality of the Helen Member ................................................................ . 13. Reference locality of the Helen Member ........................................................... . 14. Comparison of foliation attitudes southwest and northeast of the Dahlonega area ....................... . 15. Part of the Dahlonega gold belt showing major structural features ..................................... . 16. Photomicrograph of garnets in schist of the Canton Formation ........................................ . 17. Photomicrograph of chlorite after biotite in schist from the Canton .Formation .......................... . 18. Hydraulic mining near Auraria, Georgia ............................................................ . 19. Relationship between abandoned gold mines and lithology- Auraria/Dahlonega area ................... . 20. Concentration of abandoned gold mines along the Barlow Gneiss Member ............................ . 21. Concentration of abandoned gold mines in the immediate Dahlonega area ............................ . 22. Photograph of a sample from one of several zones in the pyritic schist that contain >50% pyrite ......... . 23. Determination of amphibolite protolith based on a plot of FeO*/MgO versus percentage Ti02 . 24. Determination of amphibolite protolith based on a plot of FeO*/MgO versus ppm Ni ................... . 25. Determination of amphibolite protolith based on a plot of FeO*/MgO versus ppm Cr ................... . Page 2 3 4 5 6 6 7 8 8 9 9 10 10 14 15 16 16 18 19 20 21 23 25 25 26 List of Tables Table 1. Average modal composition of New Georgia Group lithologies in the study area ......................... . 5 2. Fabric elements of the Dahlonega gold belt .......................................................... . 13 3. Comparison of fabric elements in the study area with those in northeastern Georgia and in the Greater Atlanta area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4. Major oxide and selected trace-element analyses of Pumpkinvine Creek and Univeter Formation amphibolites ................................... : ................................................. . 24 List of Plates Plate 1. Geologic map of the northeastern portion of the Dahlonega gold belt with mine locations (1 :100,000)................................................................................... . 2. Relationship between the geology and the occurrence of iron formation and tourmalinite- Dawsonville 7.5-minute quadrangle... , ................................................................... . in pocket in pocket iv THE GEOLOGY OF THE NORTHEASTERN PORTION.OF THE'DAHLQNEGA 'GOLD BELT, ' 1 ._ ~ . ';, Je,r,ey M, G~rrnan ! ABSTRACT INTRODUCTION. This investigation encompasses that portion of the Dah!onega go.ld belt extending from Canton in Cherokee County northeastward to the Georgia~ North Carolina State line, and was done to provide modern geologic information on this l'he Dahlorliega gt>ld b.elt, named for the town bf Dahlonega, Georgia, is a narrqw, ~et;~uence of r-ock units that can be mapped.f.rom <1t least the Georgia-Alabama Sfafe line northeastward to the Georgia-North t~rolina'State line, a distance area of potential e<::bnomic importC~nce. P_revious reRorts <;>n mineral resources of the study area gen~rally -~orisi~t' of site- ' ' by-site descriptio-ns of individual mines1 and, although these reports are valuable, no comprehensive studies of the geology of approximately' '152 tni (approx. 243 km) (fig. 1). Th.~ belt vari~s in thickness frorn a maximum of approximately 12.8 mi (appr.ox,-~1.2 km) in Cobb a_nd Paulding Cbunties to less than 0.6 mi (ap.prox.-1 km)' fn Rabun Coun'ty. Although gerrerally ofthe entire area were made. coinCiding With the New Georgia Group, the Dahlonega ,gold The Pumpklnvlne Creek, Canton, and Univeter Formations b('!lt is actulds. The study area is bounded by the Shope Fork (pre~ to synmetamorphic) . :given in, appendix 1.,Detailed information on the southwestern portion of the gold oelfrs found in r'epbrt!ib1 McConri'ell and and Allatoona (post-peak metamorphic) faults west and by the Chattahoochee fault (peak on the north-. to post-p'eak . '1 '~ Abrams (1983, 1984). metamorphic) on the southeast. PREVIOUS INVESTIGAliONS Gold was mined intermittently from placer, saprolite, or lode deposits inthis area from about 1829 to 1934. Gold occurs within s,ulfidic quartz veins that generally tonform to _the foliati'6n of the enclosing rock. Thase deposits occur in clo~e association with iron formation and certain felsic gneisses an-d along the contacts between amphibolite and mica-quartz schist. Data strongly suggest that the g<)ld was a priinary . 1 constituent of the metavolcanic rocks and was remobilized and concentrated within veins during regional metamorphism and deformation. The weathering of the gold deposits has resulted in an apparent supergene enrichment. This area comprises rocks that were probably deposited in a back~arc basin which experienced- an initial period of volcanism followed by extensive dasti'c sedimentation that was occasionally punctuated by brief episodes of renewed volcanism. Deposition of gold~bearing lithologies generally marked the transitions between volcanic and sedimentary processes. Many reports have been p~blished on the st(Jdy area. Most were economic in nature and ericompassE!d areas as small as one mlrie or as large as the Piedmont of the Southern Appalachians. 'fhese were mainly published dur-ing the periods 1879-1~18, 1928-1952, and 1961-1984. ' Many of the earliest repo'rts were on the immediate Dahlo'nega area. lhe first of these was by Mackintosh (1879) and was followed by a.general study'ofthe gold fields of the entire southern Appalachians by Becker (1894). General studies of gold mining in the Southeast also were puolished by Blake and jackson (1895) and Brewer (1895). The first siteby~site description of the gold deposits of Georgia was produced by Yeates and others (1896). Nitze and Wilkins (1897) described some Georgia gold deposits in their report on the gold deposits of North .<:;ar.olina and adjacent areas. Maxwell (1901) described the Crown Mountain Mine at Dahlonega, and Eck~l' (1902) and Lindgren (1906) described ' 1 ... ... _j ! I AT~ANTA r ' D O U G L A S / ~ ~ DEKALB '"____.. FULT;-O-Nj -------c ~-(// !CLAYTON;, ' _J.:: r' \_ _,_-)" ----~-~ --- I i / tFAYETTE) j HENRY \ \ ;'L~ WALTON 0 10 20 Miles 0 10 20 Kilometers Figure 1. Geographic extent ofthe Dahlonega gold belt showing study area. ' . i~ '", several deposits at Dahlonega. The first geologic map of the and hydrologic study of the entire coun~/ln 1964, the Dahlonega area was made by Keith (1909). jones .(1909) mineral resources of White County were described by Hurst published a secorid bulletin on the gold deposits of Georgia; and Otwell, and those in Habersham County were described . however, it was not as thorough as the earlier report by Yeates by Hurst and Crawford. A report by Fairley (1965) on the and others (1896). In 1918, Shearer and Hull reported on the Murphy syncline included a portion of the study area in pyrite deposits of Georgia including those in the study area. A Cherokee County. Hatcher's (1971, 1974, 1976) works on the portion of the gold belt was described by Bayley in 1928. geology of Rabun and Habersham Counties included part of Crickmay (1933), Wilson (1934), and Anderson (1934) gave the study :area. Lesure (1971) described gold mobility at the brief overviews of gold mining within Georgia, and Park and Calhoun Mine. Murray (1973) mapped a portion of the study Wilson (1936) described the deposits of the Battle Branch area for his geologic map of Fulton and Forsyth Counties. Mine and suggested a hydrothermal origin. A report by Cook (1978) described the soil geochemistry at the Franklin- Pardee and Park in 1948 covered the entire Piedmont of the Creighton Mine. Works by Gillon (1982) and Nelson (1983) Southern Appalachians. They gave thorough descriptions of described the geology of a portion of the study area in White several important mines in Georgia and in several other states. County.The geology of the Dahlonega area was described by Kline and Beck (1949) reinvestigated the massive sulfide Cook and Burnell (1983) and by Cook and others (1984), and deposit at the Chestatee Copper and Pyrite Mine. Crickmay's the geochemistry of rocks in. that area was described by (1952) report on the crystalline rocks of Georgia included a Burnell and Cook (1984). Otwell (1984) recently described the brief description of a portion of the study area. Bowen (1961) gold deposits of White County, and McConnell and Abrams and Stewart and others(1964)-studied the geology of portions (1984) d~scribed part of the study area in their report on the of Dawson County, and Sever (1964) conducted a geologic Greater Atlanta area. . ! .I J 2 STRATIGRAPHY .lntrodu.ction The study area comprises lithologies that are an extension of the New Georgia Group (McConnell atid Abrams, 1984). In the study area, units in the New Georgia Group (fig. 2) exhibit considerable variability; however, mica-quarti;schist, metagraywacke, and arl)phibolite are the most abundant. These are augmented by lesser am0unts of felsic gneiss, metatrondhjemite) ~eri,cite-quartzschist, and irori formation. Thicknesses of these units are impossible to ascertain reliably due to faulting and multiple folding, but are estimated to range from less than 100 m to several kilometers. For the same reasons, stratigraphic ()fder is problematical; however, units below are described in a probable as~ending order. They are assigned a Late Proterozoic or early Paleozoic age based qn radiometric age dates determined by Dallmeyer (1978). Pumpkinvine Creek Formation The Pumpkinvine Creek Eormation i.s a fine-grained amphi- bolite with interlayered thin units offelsic gneissand sericite phyllite (McConnell, 1980). Mapping for the present study revealed thatthis formation fornis.the core of an overturned, northwest-vergent antiform (herein called the Auraria anti- form; see plate 1, cross-se~:;tion Af,.') whose dir'ectlon cif plunge alternates from northeast to southwest several times i j::' _,, ' ' sw along its trace. The Pumpkinvine Creek Formation plunges northeastward beneath the Canton Formation on the eastern edge of Canton, Georgia (McConnell, 1980; McConnell and Abrams, 1984) and reappears approximately 15.6 mi (approx. 25 km) to the northeast. From that point it is exposed continuously northeastward to Dahlonega where it again plunges beneath the Cantor:) Formation. Cook and Burnell (1983) gave a similar structural interpretation regarding this formation in the Dahlonega area and referred to it informally as the Findley Ridge amphibolite. McConnell (1980) reports that the Pumpkinvi.ne Creek Formation occupies the limbs of an antiform southwest of the study area and can be mapped intermittently to the Georgia-Alabama State line. He also reports that his formation may be correlative with the Hillabee Greenstone in Alabama. PUMPKINVINE CREEK FORMATION UNDIFFERENTIATED 'Rocks mapped as Pumpkinvine Creek Formation undifferentiated inthe study area consist of fine- and mediumgrained amphibolite with lesser amounts of garnet-blcititehornblende~quartzplagioclase gneiss calcite and/or stauroTite, muscovite-bidtite'-plagioclase-quartz gneiss, and iron formation. The amphibolite is dark green to black in color with occasional light banding. It locally contains large laths of hornblende randomly oriented along the foliation (fig. 3). This rock has a simple mineralogy, consisting predominantly Rose Creek Schist Univeter Formation undifferentiated Helen Member Canton ~ormation undifferentiated ';i: Palrner Creek Member . 'i J ;r '','' Proctor Creek Member J=>umpkinvlne creek Formation Barlqw Gneiss Member Figure 2. Diagrammatic stratigraphic section of lithologic units in the study area. 3 ctn 0 ..0..... (Ill I 2 3 4 6 7 8 10 I I 12 13 14 Figure 3. " Chicken track" texture of an amphibolite from the Pumpkinvine Creek Formation . of green hornblende and plagioclase (albite/ oligoclase) in nearly equal proportions (table 1, sample pcu1). Accessory minerals are epidote, sphene, biotite, chlorite, magnetite, and calcite. Locally, chlorite may comprise up to 15 percent of the rock . The garnet-biotite-hornblende-quartz-plagioclase gneiss calcite and / or staurolite is locally interlayered with the amphibolite near the contact with the Canton Formation. This coarsely porphyroblastic and relatively leucocratic lithology possesses a complex mineralogy dominated by plagioclase, quartz, and hornblende (table 1, sample pcu2). The hornblende commonly occurs as radiating laths (rosettes) several centimeters across (fig. 4). Large rolled garnets up to 1.5 em in diameter are numerous. These large hornblende and garnet crystals are embedded in a fine-grained groundmass of quartz and plagioclase with lesser amounts of calcite, staurolite, and biotite. Muscovite, epidote, and chlorite are locally present. McKinstry and Mikkola (1954) described a remarkably similar lithology in the hangingwall of the ore body at the Elizabeth Copper Mine in Vermont. Iron formation units associated with the Pumpkinvine Creek Formation in the study area are quartzites that locally may contain magnetite, hematite, pyrite, arsenopyrite, mica, garnet, or unidentified manganese minerals. Volumetrically, these are minor units, attaining a maximum thickness of only a few meters. However, economically, they appear to be important indicators of gold deposits since a large number of abandoned gold mines are located along their strike. Iron formation and its significance will be discussed more fully in a later section. BARLOW GNEISS MEMBER A mappable unit of muscovite-biotite-plagioclase quartz gneiss within the Pumpkinvine Creek Formation was previously referred to as granite by LaForge and Phalen (1913) and as a sheared granitoid dike by Pardee and Park (1948) . Crickmay (1952) included this gneiss in his Wedowee-Ashland belt. This unit is herein named the Barlow Gneiss Member for exposures in the inactive Barlow Mine near Dahlonega, Georgia (Campbell Mountain and Dawsonville 7.5-minute quadrangles, fig. 5). This member is exposed in a large hydraulic cut at the indicated type locality on figure 5. The gneiss is locally interlayered with amphibolites; therefore, the boundaries of this member are the last appearances of the muscovite-biotite-plagioclase-quartz gneiss. This member is bounded by undifferentiated amphibolite of the Pumpkinvine Creek Formation. Contacts between the gneiss and amphibolites are sharp. The Barlow Gneiss Member is a medium- to dark-gray rock that has a pin-striped appearance in most exposures. Porphyroblasts are usually present as flattened crystals or crystal aggregates of either blue quartz or plagioclase up to 0.5 em in diameter (fig. 6) that may be recrystallized crystal fragments. Thin sections of the gneiss show slightly altered plagioclase porphyroblasts embedded in a fine-grained groundmass of quartz, plagioclase, biotite, and muscovite (table 1, sample big; fig. 7). The amphibolites are dark green to black in color and locally exhibit light banding. Their mineralogy is principally plagioclase and hornblende with accessory epidote, sphene, magnetite, chlorite, and calcite. The Barlow Gneiss Member is well exposed and was used as a marker horizon in deciphering the structure of the area. Its outcrop pattern defines a regional, northwest-vergent antiform and, although generally relatively thin, this member can be mapped from just southwest of Dawsonville to Dahlonega, a distance of approximately 14.7 mi (approx. 23.5 km) (plate 1). Mineralogical and field evidence strongly suggest that the Barlow Gneiss Member represents the metamorphosed felsic phase of a predominantly mafic volcanic sequence . The areal extent, mineralogy, and texture of this member strongly suggest that its protolith was a crystal tuff. The Barlow Gneiss Member is lithologically similar to and may be correlative with the Gaits Ferry Gneiss as described by McConnell (1980) and McConnell and Abrams (1984). 4 Table 1. Average Modal Composition of New Georgia Group Lithologies in the Study Area. pcu1 pcu1 big PC, PC:~ pic cs, c~ h, Quartz 31 48 56 64 56 40 50 31 Plagioclase (albite/oligoclase) 40 23 23 3 50 44 tr Hornblende 53 23 4 Biotite tr 3 13 32 20 36 7 6 Muscovite 2 12 3 3 tr 3 2 43 Garnet 7 8 10 2 16 Chlorite 3 8 tr tr tr tr Epidote 2 tr 2 tr Sphene 2 Magnetite tr tr tr Calcite tr 3 2 tr tr Staurolite tr 2 Tourmaline Kyanite tr Pyrite Graphite 3 tr pcu - Pumpkinvine Creek Formation undifferentiated big - Barlow Gneiss Member pc - Proctor Creek Member pic - Palmer Creek Member cs - Chestatee Member h - Helen Member unu - Univeter Formation undifferentiated hl unu1 unu1 62 5 45 13 43 8 50 3 21 35 2 tr 3 tr tr 2 tr tr 5 tr - -- - - - - - - - ern 0 0""".1=1 em I 2 3 4 5 6 7 8 9 10 I I 12 13 Figure 4. Radiating hornblende crystals in the coarsely porphyroblastic facies of the Pumpkinvine Creek Formation. 5 Figure 5. Type locality of the Barlow Gneiss Member of the Pumpkinvine Creek Formation (Dawsonville and Ca mpbell Mountain, U.S. Geological Survey 7.5-minute topographic quadrangles). 0 I Of.'lm -= 1 em 3 4 5 I I 12 13 14 15 16 Figure 6. Sample of the Barlow Gneiss Member showing flattened porphyroblasts. 6 Figure 7. 0 .3 mm Pol ycrysta llin e pl ag ioclase porph yro bl ast (Barlow Gn eiss M ember) embedded in a fi ne-grain ed matri x. Canton Formation The Canton Formation consists of graphitic garnet-mica schist, metagraywacke, and phyllite (McConnell and Abrams, 1984). This unit can be traced into the study area from the southwest at Canton and is traceable from there northeastward to the Lake Burton area northeast of Helen, Georgia, a distance of approximately 64 mi (approx. 107 km) . Most lithologies within this unit appear to be metasedimentary in origin. In the study area the Canton Formation consists of garnet-biotite-muscovite-quartz schist, biotite-muscovite quartzite, graphitic quartz-sericite schist, hornblende-biotite-quartz schist, muscovite-biotite-quartz schist, biotiteplagioclase-quartz gneiss, plagioclase-biotite quartzite, and amphibolite. Several of the above lithologies are individually mappable while others are components of a mappable sequence. Four members for the Canton Formation can be recognized . They are formally named and described below. PROCTOR CREEK MEMBER Lithologies that are herein named the Proctor Creek Member of the Canton Formation were previously mapped as Carolina Gneiss by Keith (1909) and as the WedoweeAshland belt by Crickmay (1952). This member is named for exposures along Proctor Creek near Dawsonville, Georgia (Dawsonville 7.5-minute quadrangle, fig. 8) . The dominant lithology at the indicated type locality on figure 8 is a muscovite-garnet-biotite-quartz schist (table 1, sample pc1). This schist has a fine- to medium-grained texture and a silvery luster on cleavage surfaces . Subhedral garnets approximately 3 to 5 mm in diameter are common . Accessory minerals include magnetite (?), chlorite, and calcite. Thin lenses of calc-silicate material (i.e., garnet-hornblende-quartz-plagioclase hornfels) 1 to 5 em thick are common. In the Dahlonega area the schist possesses a somewhat different texture marked by coarse porphyroblasts (?)of altered plagioclase rimmed by garnet and biotite (table 1, sample pc2) and locally is more gneissic than schistose. At several locations, distinct layers with coarse porphyroblasts 4 to 8 mm in diameter alternate with layers having fine porphyroblasts 1 to 3 mm in diameter (fig. 9). The interpreted lower boundary of the Proctor Creek Member is the first appearance of iron formation or amphibolite of the Pumpkinvine Creek Formation . This contact is sharp in most exposures and was interpreted as a fault in the immediate Dahlonega area by Cook and Burnell (1983) . The interpreted upper boundary is the first appearance of darker, muscovite- and garnet-poor schist of the Palmer Creek Member (this study) . This contact is poorly exposed but is believed to be gradational. The Proctor Creek Member is exposed in the limbs of the Auraria antiform from the vicinity of the Dawson-Forsyth County line northeastward to Dahlonega (plate 1). Characteristics of this member at most exposures suggest a shale as its protolith ; however, the coarsely porphyroblastic facies exposed in the vicinity of Dahlonega (fig. 9) could be interpreted as a metatuff. 7 Figure 8. Type locality of the Proctor Creek Member of the Canton Formation (Dawsonville, U.S. Geological Survey 7.5-minute topographic quadrangle) . Figure 9. Banded nature of the coarsely porphyroblastic facies of the Proctor Creek Member. 8 PALMER CREEK MEMBER The Palmer Creek member is exposed in the limbs and lithologies herein named the Palmer Creek Member of the Canton Formation were previously mapped as Carolina Gneiss (Keith, 1909) and as Wedowee-Ashland belt (Crickmay, 1952). This member is named for exposures along Palmer hinge of the Auraria antiform from the vicinity of the Dawson/Forsyth County line northeastward to the Dahlonega area. This member probably is a metamorphosed sequence of fine-grained ~!'!diments with minor mafic tuffs or flows. Creek near Dawsonville, Georgia (Dawsonville 7.5-minute quadrangle, fig. 10). At the designated type locality on figure CHESTATI:E MEMBER 10, biotite-quartz schist hornblende and/or garnet is the The sequence of lithologies herein named the Chestatee dominant lithology. Garnet-biotite-muscovite-quartz schist Member was previously /napped as Roan Gneiss by Keith and minor amphibolite are present locally. The biotite-quartz (1909) and as part ()f Crickmay's (1952) Wedowee-Ashland schist is fine- to medium-grained and cleaves readily intp thin belt. This member is named for exposures along the Chestatee plates. It locally contains small almandine garnet crystals .River iri lumpkin County, Georgia (Murrayville 7.5-minute approximately 2 mm in diameter. Hornblende crystals locally qulildrangle, fig. 11). At the, indicated type locality (fig. 11 ), as at occur as somewhat ragged laths up to 1.5 em long randomly other exposures, several lithologies are present. They include, oriented along the foliation planes. Accessory minerals are in order of abundance, amphibolite, hornblende-plagioclase epidote, plagioclase, magnetite (?), and c~lorite (table 1, gneiss, muscovite-biotite-quartz-plagioclase gneiss (table 1, sample pic). Locally, this lithology. has a gneissic texture sample c~ ), and muscovite-pyrite-plagioclase-quartz gneiss defined by alternating bands of biotihHich and biotite-poor zones that resemble original sedimentary features. The (table 1, sample cs2). The amphibolite is dark green to black . and ex~ibits textures ranging from finely equigranular to garnet-biotite-mUSCOVite-quartz Schist is n:'OSt abund~nt ih . coarsely porphyroblastic. In the coarsely porphyroblastic the Dahlonega area and is similar texturally to the biotite- rock, leucocratic porphyroblasts occur either as single plagio- quartz schist. The presence of muscovite gives this rock a ,lighter color and luster. Amphibolites occur as th.ih units clase c~ystals- resembling metamorphosed phenocrysts or as crystal aggregates of dino~oisite resembling metamorphosed composed of nearly equal afnounts of hornblende and amygdules. The horriblende-plagioclase gneiss appears to be plagioclase. Most ofthe amphibolites are not mappable at the a hornblende-poor variety of the amphibolite. The muscovite- 1:24,000 scale. .biotite-quartz-plagioclase gneiss is a medium-gray rock with The boundary between the Palmer Creek Member and the a generally homogeneous texture. Porphyroblasts of quartz Proctor Creek Member is the last occurrence. of the biotite- and/or plagioclase approximately 1 to 3 mm in diameter are quartz sthist; .The boundary.-, between the Palmer Creek , conspicuous.,- This lithology closely resembles the Barlow Member and the Chestatee Member (this study) _ls the first Gneiss Member of the Pumpkin~l.ne .C~eek..fqr,matioii. The occurrence of interlayel"edf~lsie gneiss and amphibolite; The muscovite-pyrite-plagioclase~qua~tz:- gn~iss is a very leuco- contact with .the Proctor Creek Member. is -gradational;.,- craticrockwitha uniformtexture~ Fine laminations of pyrite whereas the contact with the ChestateeMember is .a fault; and muscovite are locally present. Where the Chestatee-Member is absent (plate 1), the f!almer -.The Chestatee Member:is in shar-p:contactwith the Helen Creek Member grades into the Helen Member (this study). , Member (this study) to the southeast.,a':Jd;i~;~ filult cont11ct !Nith The boundary of the Palmer Creek Member in this case Is the the Palmer Creek Member to the northwest (plate 1)_. The first appearance of biotite-plagioclase-quartz gneiss (meta~ graywacke) of the Helen Member. Figure 10. Type locality of the Palmer Creek Member of the Canton Formation-(Dawsonville, U.S. Geological Survey 7.5-minute topographic quadrangle). Figure 11. Type locality of the Chestatee Member of the Canton Formation (Murrayville, U.S. Geological Survey 7.5-minute topographic quadrangle). 9 :'1 boundaries of the Chestatee Member are the first occurrences of biotite-quartz schist of the Palmer Creek Member to the northwest and metagraywacke of the Helen Member to the southeast. The Chestatee Member is exposed from near Dawsonville in Dawson County northeastward to the Cavenders Creek area in Lumpkin County (plate 1), and its trace forms a distinct topographic lineament. This member probabiy represents a metamorphosed sequence of felsic and mafic crystal tuffs and mafic flows. HELEN MEMBER This sequence of rocks was previously designated as part of the Carolina Gneiss (Keith, 1909) and as part of the WedoweeAshland belt (Crickmay, 1952). More recently, Gillon (1982) informally termed these rocks the Helen sequence for exposures in the vicinity of Helen, Georgia. This terminology was alsq employed by Nelson (1983) and Nelson and Zeitz (1983) for rocks in the same area. To avoid confusion the name Helen is retained for this sequence and herein named the Helen Member of the Canton Formation for exposures in the vicinity of Helen, Georgia (Helen 7.5-minute quadrangle, fig. 12). At the indicated type locality (fig. 12), and elsewhere, biotite-muscovite-quartz schist garnet and biotite-plagio- clase-quartz gneiss (metagraywacke) are the dominant lithologies. Plagioclase-biotite quartzite and minor amphibolite may be locally present. Additional exposures may be observed at a reference locaiity along Georgia Highway 60 south of Dahlonega (Murrayville 7.5-minute quadrangle, fig. 13). The biotite-muscovite-quartz schist garnet and the biotiteplagioclase-quartz gneiss (metagraywacke) occur as an intric~tely interlayered sequence where alternation of layers of equal thickness is common. The schist (table 1, sample h1) is light gray to light brown in color and overall fine to medium grained. It is richer in garnet and muscovite in the southwestern half of its exposed length, becoming garnet-poor, slightly feldspathic, and biotite-rich to the northeast. Where garnetiferous, the largest garnets are approximately 0.5 em in diameter, euhedral, and exhibit a rolled (pinwheel) texture. Staurolite, chlorite, magnetite(?), and tourmaline are accessory minerals. Graphite is locally abundant. The biotite-plagioclase-quartz gneiss (table 1, sample h2) is medium gray in color with an overall "salt and pepper" appearance. The gneiss is locally conglomeratic with clasts consisting of quartz or plagioclase less than 0.5 em in longest dimension. Matrix '<>, Figure 13. Reference locality of the Helen Member of the Canton Formation (Murrayville, U.S. Geologital SLjrvey 7.5-minute topographic quadrangle). :I ;j :d ; i I I ,1 i.,i. I ll II il II II 'I ' I I Figure 12. Type locality of the Helen Member of the Canton Formation (Helen, U.S. Geological Survey 7.5-minute topographic quadrangle). 10 material consists of a fine-grained mixture of quartz and plagioclase plus lesser amounts of biotite, muscovite, garnet, and epidote. Fin~ laminations and graded.beds are observ~.ble'. in hand sampl~s and thin sections. In som.e exposures northeas.t of Pahlone~a~ the quartzcontent;i~ hish e'?ough , (greatet than 70 percent) to .classify this lithology. as .a qua'rtzite. The amphibolites occ:;ur as thin units )nterbedd.ed with the above-mentioned schist and. graeiss.. Spme )lr:nphi-. bolifes are easily mapped over long distances and, therefore, were used as stratigraphic marker horizons. Their mi'neralogy consists predominantly of plagioclase and hornblende with accessory sphene, epidote, chlorite, and magnetite(?). Locally, chlorite and epidote are abundant. The Helen Member (plate 1) grades into the Urtiveter Formation (this study) and Hatcher's (1974) Tallulah Falls Formation to the southeast and the Palmer Creek Member and Hatcher's (1974, 1976, 1979) Coweeta 'croup to the northwest. It is in fault contact with undifferentiated amphibolite and schist a'nd Gillon's (1982) Richard RU?sell formation to the northwest. It is. in sharp contact with the Chestatee Member, also to the northwest. The boundaries of the Helen Member are defined as the last occurrence ofinterlayered metagrayWacke and biotite-muscovite-quartz schist. . The Helen Member i~exposed trom just southwestof Lake Burton in Habersham County, where it pinches out, to the vicinity of the Dawson-Forsyth County line, where it is no longer distinguishable from undifferentiated.Canton Formation. The mineralogy, textures, and internal stratigraphy of this member strongly suggest a. predominantly sedimentary origin .. The repetitive nature of the gneiss-schist sequence a resembles part of turbidite sequence. This member probably was deposited in. a rapidly subsidiJ;lg basin that. had an occasicinal episode. of volcartie activity, '' Univeter Formation The IJnivet'er Forrnation.is>.the.most regionally.,extensive forrriatlon in the study area, It is exposec;lfrom near Canton in Cherokee County to Lake B~rt(>n in Hab~rsham County, its trace forming a regional topqgra'phic lineament. Near Canton the Univeter Formdase~gatnet-blotite~muscbVite.:.. quartz schist, biotite-quartz sch,lst garnet, hornblendeL plagioclase gneiss, and amphibolite biotite an'd/br garnet. The t>verall composition of this assemblage is similar tothe lowE!rm0stmember:of theJallulah Falls Formatioh (Hatch~r, ,1~71;.1974, W?f;,),,byi:sin~e It exhibitsmllch vari~'fitlHaiM~ :,strikt;~;; it Js ,d~slgnated. here:as :tallulah falls: 'Fbrfflation ;.undifferentiate.d. This assemblage is intrudt(d b}''a gtiel~sictb coa~sely pc;>rphyroblastle; leucm:irati<:: musd:Mte-biotife'qwartz r,t)~nzonitegn~iss.(Rabun Gheiss cif Hateh~r; 1974/1976)\': ~; ,; ' ' ,' ' ' ' - ,' ' : , ""' I i , " "J ' ' ~ ~ 1 ~ i. ' ' ' lntruSiv.~ RoCks: ~:. -.,;. ~: 'i (.r : ., Several types of intrusive rocks are present ih the stUdy ':ar~a:They are either fefsk; mafic,or ultramaficin:tomposlti9n and of limited areal extent. Three relative.ly large Intrusive bodies are found in the Dahlonega area (piate 1). Th~y consist of 'two micaceous "granitic" ,,bQdies,, and: .one il}mphibpl~: bearing "granitic" boqy. The micaceous bodies are t:mWsely crystalline, leucocratic.rocks and have a weakly to moderately well-developed foliation. Biotite and muscovite together comprise approximately 15 percent of the rock. Sericitization and kaolinlzatlon of .feldspars makes their identification difficult, althoug~ identifiable feldspars are clearly plagioclase. No K-feldspar Was observed. The. quartz content is high, ra,nglng from 65'to 70percent. The easternmost micaceous "granitic" body was referred to as the Benning granite (Jones, 1909). The amphibole-bearing body has a similar textUre and of mineralogy and. is also altered. Amphibole makes up 10 percent of this rock. The degree of altetation and thE!.lack suff(cient data pl',event a concise classification of thes~ bodi~s at although the.y have been referred to. recen'tly met~~ trondhjeniites (~ook afld others, 1984). These bodies c;:rossc~;~t rocks within the anton Formation and are locally intedayered with the co.tmtrY..rock. , Two biotite trondhjemite dikes are present on the Dillard Quadrangle. Th~ dikes are unmetamorphosed, leucocratic rocks that consist of a'lblte (72%), quartz (25%), and biotite (3%). Both dikes strike northeast and are undeformed. 11 Hatcher (1974) assigned them a late Paleozoic age based on their unmetamorphosed character. Mafic intrusive bodies are represented in the study area by olivine diabase dikes. Almost all are confined to the extreme northeastern end of the study area. The dikes are clearly the youngest rocks in the study area as demonstrated by their crosscutting nature. All those examined contain from 10 to 23 percent olivine, are less than 3m wide, and strike northwest. A few can be traced for several kilometers. A dike on the Ball Ground East quadrangle in Cherokee County cuts the trace of the Allatoona Fault. - The ultramafic bodies in the study area are found within the Tallulah Falls Formation and consist of small, isolated, de- formed masses largely altered to serpentine and/or talc. Those bodies that are not thoroughly altered were recognized as enstatite and/or diopside-bearing dunites. These ultramafic bodies apparently were emplaced prior to the peak of regional metamorphism. Rocks Northwest and Southeast of the Study Area Units that border the study area on the southeast include the Sandy Springs Group and the Tallulah Falls Formation (plate 1). The Sandy Springs Group was described by Higgins (1966, 1968) and later defined by Higgins and McConnell (1978). The Sandy Springs Group consists of biotite gneiss, muscovite-biotite schist, amphibolite, micaceous quartzite, and kyanite-staurolite schist. Migmatization is locally intense. The Tallulah Falls Formation, as defined by Hatcher (1971, 1974, 1976), consists of amphibolite, quartz-plagioclasebiotite-muscovite gneiss, muscovite schist, muscovite-garnet schist kyanite sillimanite, and quartzite. Because of the similarities between the lithologies that make up the Sandy Springs Group and Tallulah Falls Formation, Higgins and McConnell (1978) and Hatcher (1974) considered them to be equivalent. Those units on the northwest include the Great Smoky Group, Coweeta Group, and Richard Russell formation (plate 1). Great Smoky Group lithologies were recognized to the northwest of the study area between Canton and Dahlonega by Sever (1964), McConnell and Costello (1980, 1982), Costello and others (1982), and McConnell and Abrams (1984). The Great Smoky Group consists of metagraywacke, locally conglomeratic metasandstone, metasiltstone, muscovite-biotitequartz schist kyanite, meta-arkose, and minor amphibolite. Northeast of Dahlonega the study area is bordered by a sequence of lithologies informally termed the Richard Russell formation by Gillon (1982). This unit consists of migmatitic biotite gneiss, garnet-sillimanite-biotite schist, garnet-biotitemuscovite schist, and minor amphibolite. The Coweeta Group is also found along the northwestern border northeast of Dahlonega. Hatcher (1974, 1976, 1979) defined the Coweeta Group as a sequence of muscovite-biotite-quartz-plagioclase gneiss, micaceous quartzite, muscovite-biotite-schist, metaconglomerate, and metagraywacke. Rocks adjoining the study area due north and northwest of Dahlonega have not been studied in detail. They consist of amphibolite, biotite-quartz schist, and biotite-muscovitequartz schist and may be correlative with Gillon's (1982) Richard Russell formation or other lithologies that comprise the Hayesville thrust sheet as described by Nelson (1983). STRUCTURE The structural complexity of the Dahlonega gold belt has long been recognized. Crickmay (1952) characterized this area as a complex zone of pervasive shearing and suggested the existence of extensive faulting. Because of this, he referred to this area as the Dahlonega shear zone. Observations made during the mapping phase of this study tend to corroborate Crick may's remarks on shearing; however, the primary cause for shearing appears to be extremely tight folding rather than faulting. Faulting is present but is largely confined to the borders of the study area. Three major faults form portions of the boundaries of the study area (plate 1). The Chattahoochee fault forms most of the southeastern boundary, whereas the Allatoona and Shope Fork faults form part of the northwestern boundary. All juxtapose significantly different geologic terrains. The Chattahoochee fault was first proposed by Hurst (1973), and its trace was subsequently modified by McConnell and Abrams (1982). As observed in the study area, it forms a distinct boundary between the weakly to highly migmatized Sandy Springs Group and unmigmatized schists, amphibolites, and felsic gneiss of the Univeter Formation. Bowen (1961 described cataclastic textures associated witfrthis boundary in southeastern Dawson County, and McConnell and Abrams (1984) described this boundary as a metamorphic isograd and migmatitic front. This fault was traced by the author from just southwest of Lake Burton in Habersham County southwestward to central Cherokee County. McConnell and Abrams (1984) traced it farther southwestward where it is overridden. by the Blairs Bridge fault. Hatcher (1978) proposed that one of'the faults on the northwestern boundary of the study area was a continuation of the Hayesville fault which had been observed farther to the northeast in North Carolina. This fault was subsequently called the Allatoona-Hayesville fault by McConnell and Costello (1980). In this report the Allatoona-Hayesville fault is referred to simply as the Allatoona fault. Movement along this fault probably occurred shortly after the peak of regional metamorphism since it truncates the northwestern limb of the Auraria antiform (see cross-section AA', plate 1). Along the Allatoona fault, terrain of the Dahlonega gold belt with a substantial volcanic component was thrust over the predominantly sedimentary Great Smoky Group, forming a distinct boundary between dissimilar terrains. This fault terminates northeast of Dahlonega near the trace of the Shope Fork fault. The Shope Fork fault was mapped by Hatcher (1976) through Towns and Rabun Counties and was extended into White County by Gillon (1982). Hatcher (1976, 1979) considered movement along this fault to have been pre- or synmetamorphic. The Shope Fork fault can be traced across Lumpkin County north of the study area and separates lithologies resembling the Canton Formation from the Richard Russell formation (Arthur E. Nelson, personal commun., 1984) (plate 1). The only major fault observed within the interior of the study area is a reverse fault that extends from just southeast of Dawsonville to northeast of Dahlonega where it merges with the Allatoona fault. Movement along this fault transported the Chestatee Member to its present position and is believed 12 'j: ''. responsible for the discontinuity in strikes between units on of the Dahlonega area and southeast-vergent northeast of either side. This fault is probably a splay off the Allatoona fault there and plunge either southwestward or northeastward. (see ~ross~section AJ:.',. plate 1) . Thickening ofunits in the axial areas and thinnil"'gin the limbs .Tne mc:tjor structural feature of fhe mifitonega belt is the Aura ria antiform, a large, asymmetrical, isotlin~l antiform (plate 1), Jhis fold is northwest~ve~genfan8pluriges alternately s.ugg~sta flex!Jral flow type of foid~ihg; SubsE;!qu~ntto D2 was anotl'rer episode of deformation (D3 ) .of grea~ly reduced, although quite Widespread, lntensity."fhis northeastwardanp s9uthwestwar4alorig sfdke. This arttiform extends frorp :P.~uldiflg County (McConnell, 1980) .Mrth~ast~ event (03 ) is characterized by small folds mote open than F1. T~es~ folds (F2) are co~axlal' With F1 folds and also plunge . ward to just east of Dahlonega in Lun1pkin C:oUnty'a'n'd is . responsible forth~ outcm~ p~her:ns of major lithold~ies in this area, In Pauldmg, Bartow, and Cherokee Counties the Auraria antiform is cored by the Gaits Ferry Gneiss (McConnell, either southwestward or northeastward. They have a wave- l~ngth qf less than 1 meter and are commonly the most easily recogn'i~ablefolds at individuMoutcrops. These' folds (F2)are accompanied by a pervasive cre~lilatioti cleavage. 1960; McCpnnell ~nd Abrams, 1984), '1\fhereas 'in the. study area it is con~d by the structurally 'overlying Pumpkinvine The last deformational event (D4) had~ subtle effect ori the outcrop patterns of c;ertain lithologies. This eve'i'lt is charac~ .CreekJormi}tipn. . . ., . .The f~bric of the lithologies in the study area reflects several episodes qf deformation. Collectively, they record a succ~ssion terized by southeasHrending(?) cipeh fblas (F3). This 1 e~ent appears to be responsibl~ forth~ somewhat abrupueversal of foliation dips northeast of Dahlon~ga ih th~ vicinity .of the of.events ofini~iallystrong ductile deformatioh foll6\lyt:!d by eplsod~s of r.ela,tively. '1\feakprit~!edefOrm~tlo:n. 'tk~, ~~ctile .. Lumpkir~Whit~ <;:ounty line (fig. 14; also, compare ctoss~ sections AA' and BB', plate'1) and the sinusoidal trace'0f the p,hase 1s expressed by flexural floW.folds, where~s tllel:itlttle phase is ,expressed by sliCkensides and small fault~. 'fheseare Auraria antiform also' in the vicinit{ofbahlotfega'(plt~te 1). Also associated with this event are small, high~angle normal summarized .in table 2 and discussed .in the ensylng text:: The e<}rli~st recognizable event .(D1) is faulting. alo.ng the Shope Fork fa1Jit. Any induced fabric that may have acc.om~ . pahied thi.s mpvement is not recogni.z~ble in the study area, probably .due to subsequent over~pririting. 1' . faults with displacements of only a fell\(;centii;T)eters. The fault planes are generally parallel to a ~~gional joint set and probably ref,lect movement alon!fpreviollsiy established joint .. sets, .Numerous slickens'ides accotnpa'ny these faults. ,,n to Ahi:Jis point it is worthwhile compare stnictural;fabric The.next recognizable deformational event(D2) is the most elements of the study area to those observed'in previous intE)fiSe and is.re~ppnsiblefor the ()Utqop patterns and major investigations of adjacent areas, ,Table 3 :stJrtJmai'izes and f.olds (F1) of, the St\JdY area. T~ is' e~erlt ,pr<;>duced a pervnsive . ,. <;om pares fabri.c elementsiqbs~rv~d in this' stu'dy with' those northeast-striking foliation that is a'xial pl~hiil' to tKesefolds. Minor and major folds prodused durh1~ 'th!s::r:~v,ent) are extremely tight isoclines that are ri~rthwest.:.verg'enlsoutliwest ops,e.rvedi by Mc.<:;onnell and /\brc!ms (-1984) iri th~ Greater Atlant<1area andby~,Hatcher arl~Hutl'er (1979) IHihdrtheastern Georgia. One interestin!(observatlort :is the'; ab~~nce of . . . . J~ ~ > ' , ' ~ , . ;,\t .' Table 2:Fab~ic .Elements. of the Dahlonega Gold Belt , (Cheroke~ County-.to Habersham. County) . ' ''. J Generation Fold Style . Orientation' Typh oflineations; Tir,ning Sig' nifi,c..a.n..t.Fe:a:tures ; ; D1 . Pre~to synmeta~ ,tylov~ment along ,1.; m9rphic . shopeF?rk fault. Tight isodin'esf . NE strike; N~ .or Elongation Ne'ar peak of For rn.a t ion qf flexutalflow folcds, SW plunge; NW thetrnal hletamot~ Auraria antiform; or SE Yergent. , ph ism. majortectonicshor~ tening; develop~ ment of dominant s~surface; move7 ' ment along Chatta~ 1 hoochee faultW .. l.soclinal to opE' in; Cc:i~axialto F1 flexural flow folds. Intersection; ,.Post~peak to No mesostopic crenulation axes post~metamorphic expression; move~ trenulation clea~ rrtent along Alla- vage. toona fault. Broad, upright ~E trent;! SW vergent(?) None recognized Post-metamorphic. Responsible fdr shift in dip,s qf re~ gional foliation NE of Dahlonega (?) and. folding of Auraria antiform. 13 SW of Dahlonega Area N NE of Dahlonega Area N B 1m strike -dip Figure 14. Comparison of foliation attitudes southwest (A) and northeast (B) of the Dahlonega area. evidence for Hatcher and Butler's (1979) F1 and F2 and McConnell and Abrams' (1984) F1 in the study area. Another is the correlation between the writer's F1 , Hatcher and Butler's (1979) F3, and McConnell and Abrams' F2. This strongly suggests that the extremely tight folding in the study area (F1) may have completely obliterated any evidence of earlier folding. The correlation between the writer's F1 and McConnell and Abrams' (1984) F2 is also suggested when foldinduced outcrop patterns in part of the Greater Atlanta area and part of the study area are compared (fig. 15). MET AMORPHISM Several workers have noted that the Dahlonega gold belt exhibits a distinct mineral assemblage indicative of a slightly lower metamorphic grade than the surrounding terrains (Gillon, 1982; Nelson,.1983; McConnell and Abrams, 1984). This feature is constant th~o.ughout the study area and served in the past, and in this study, as partial criteria for the delineation of the boundaries of the gold belt. lithologies in the study area are within the staurolitealmandine subfacies of the almandine-amphibolite facies of regional metamorphism as described by Turner and Verhoogan (1960). This subfacies is characterized by assemblages of quartz, muscovite, almandine, biotite, plagioclase, and staurolite for derivatives of pelitic rocks and by hornblende, plagioClase, almandine, and epidote for derivatives of basic rocks. Staurolite is a key mineral of this metamorphic grade, although kyanite may be rarely present in very aluminous rocks. These assemblages closely reflect those found in fhe lithologies of the study area. Notable deviations include the low anorthite composition of the plagioclase (An10 - An20 ) compared to the norm (An25 - An45 ) given by Turner and Verhoogen (1960) and the coexistence of chlorite and hornblende in some of the basic rocks. These deviations are probably vestiges of green schist facies and, therefore, represent the transition between two metamorphic facies. One period of prograde regional metamorphism produced the mineral assemblages described above. This event reportedly occurred in the Northern Piedmont approximately 365-million years ago (Dallmeyer, 1978) and was marked by a combination of dynamic and thermal process~s. Mineral textures in certain lithologies suggest that thermal metamorphism continued after the most intense deformation ceased. This is revealed in schists of the Canton Formation by garnets with deformed cores and undeformed rims (fig. 16): and by the presence of a set of anhedral an~a set of euhed'ral, garnets. A very weak episode of retrograde metamorphism also can be observed. This episode manifests itself in the slight alteration of biotite to chlorite in the schistose lithologies (fig, 17). This alteration is present throughout tlie study area and was reported in adjoining terrains (Hatcher, 1979; McConnell, 1980). Table 3. Comparison of Fabric Elements in the Study Area with those in Northeastern Georgia and the Greater Atlanta Area. Northeast Georgia (after Hatcher and Butler, 1979) Greater Atlanta Area (after McConnell and Abrams, 1984) This study F1 Isoclinal recumbent EW-NE rend (S, rarely observed) Not recognized Not recognized F2 Isoclinal recumbent EW-NE F1 Isoclinal recumbent ENE trend; trend, dominant 5-surface. dominant 5-surface. Not recognized F3 Upright isoclinal to open, NE trend. F2 Upright to overturned; isoclinal to open; NE trend; responsible for outcrop patterns. F1 Extremely tight isoclines; NE trend; NW & SE vergence; dominant S-surface; responsible for outcrop patterns. F4 Crenulation cleavage, NE trend. F2a Upright, open, NE trend .. F2 Isoclinal to open; co-axial to F ; crenulation cleavage. Not recognized F3 Open to isoclinal; SW vergence; 5E trend; mainly restricted to Blue Ridge. Not recognized F5 Upright, open, NE trend. F6 Upright, open, NW trend. Not recognized F4 Upright, open, NW trend. Not recognized F3 Broad, upright, 5E or NW trend. I I 14 J 'I 't.' J, spng ,;, ;I! ,.E:XPLANATIOff (not In stratigraphic order) I oa I Car)t9n. Forma~iq~, ,,, ,,. , ,: I~o I kellogg; ~,real<' Mafic OO'mplex ' 1 ' ';j.uo 1, Uhiv~ter,~nd Oa~ton fo~;,ations ] Pumpklnvine Creek Formation ,lacgl Acworth Gneiss jaugl Austell Gneiss jshgl Sand J:1.iH Gnerss I lmo Mud creek Formation I I to Taliadaga Belt I I os Ocoee Supergroup ~pngl Sandy Springs and New . Georgia Groups ~ Corbih.;Gnelss Complex ~ Gaits Ferry Gneiss ~ Sandy Springs Group ' X;\ .. ~. figure 15. Part of the Dahlonega goI~ belt showing major structural features. F2 outcrop:r;atterns imd unit names on the western half are after McConnell (1980) and McConhell aiid Ab~ams .(1984). 15 1 mm Figure 16. Garnets in schist of the Canton Formation exhib itin g rotated cores with later euhedral overgrowths. 0.3 mm Figure 17. Chlorite (ch i) after biotite in schist from the Canton Formation. 16 ECONOMIC GEOLOGY Introduction Gold was mined in Georgia almost continuously from about 1829 to 1934 (Paradee and Park, 1948). The intensity of mining activity during this period varied due to the price of gold, the political climate, the depletion of certain types of deposits, and the introduction of new mining technologies. Recorded production during this period for the entire State was just over one-half million ounces (Pardee and Park, 1948). The production breakdown for specific areas of the State is not possible, but clearly the Dahlonega belt accounted for the majority of this amount. Production overall was probably considerably higher than that reported since records were not always kept. Mining History and Methods I As in most gold-producing regions, mining methods evolved in response to the depletion of certain types of deposits and the discovery of others. Mining activity in the Dahlonega belt began as placer mining of stream gravels, and, subsequently, extensive areas in the study area were mined in this fashion; some placers were reworked several times. The initial boom associated with this type of mining lasted from 1829 to abol)t 1834 (Pardee and Park, 1948), but the inevitable depletion of the known placer deposits resulted in a period of greatly reduced activity. The advent in 1868 (Pardee and Park, 1948) of the Dahlonega method of hydraulic mining of saprolite resulted in a renewed surge in activity. This method involved the removal of a large volume of material by the use of a stream of water under high pressure. The relatively soft saprolite was literally washed from the hillsides into a network of sluices from which the gold was collected. Extensive open cuts were made by this method (fig. 18). Hydraulic mining seems to have remained popular up to the time production ceased in the Dahlonega belt. In several areas extensive underground mining was undertaken, and in most instances, this phase of mini~g succeeded hydraulic methods once unweathered rock was reached. Underground mining in fresh rock was greatly facilitated by the development of a chlorination process for extracting gold from unoxidized sulfidic ore. It is common to see ad its and shafts extending outward in numerous directions along veins at old hydraulic cuts. In other areas, however, most of the activity consisted of underground workings in both fresh rock and saprolite with only a limited amount of surface activity. This full progression of mining methods seems to have occurred in only a few areas. Overall, placer mining was the most widespread followed by hydraulic mining of saprolite. One reason for the preponderance of these two mining methods over underground methods was that the cost of placer and hydraulic mining was much less. Another is that the weathered portions of the deposits and the placer deposits derived from them tended to contain more gold than fresh rock, probably as a result of mechanical and supergene enrichment. Lesure (1971) was able to demonstrate supergene enrichment of the weathered part of the gold deposit at the Calhoun Mine in Lumpkin County and suggested that this characteristic of the deposit determined the type of mining methods employed there. Supergene enrichment can be assumed for many gold deposits in the study area, but this does not necessarily indicate that unweathered deposits will have a gold content below ore-grade. A prime example of an unweathered, high-grade deposit is the lode atthe Franklin-Creighton Mine in Cherokee County that contained gold in amounts up to 1.49 oz/ton (Jones, 1909) to a depth of several hundred feet, a depth well below the effects of weathering. Occurrence and Genesis of Gold The deteriorated condition of most of the abandoned mines frequently inhibited thorough observations at these old workings. For this reason the observations made by Yeates and others, (1896), Lindgren (1906), jones (1909), and, particularly, Pardee and Park (1948) were used extensively. These early workers indicated that the gold occurs in veins that conform, in most cases, to the foliation of the enclosing rock. These veins are composed. predominantly of quartz with lesser amounts of sericite, biotite, carbonate, pyrite, pyrrhotite, and garnet. Galena, sphalerite, arsenopyrite, chalcopyrite, amphibole, iron oxide minerals, and feldspar were also reported. The geometry of the veins varies widely but is generally tabular, lenticular, or in rare instances, rod-shaped or very irregularly shaped. The veins occur singly or as a zone of several bodies. More detailed descriptions can be found in the above reports. When plotted on geologic maps, abandoned mines are concentrated in certain areas. These cpncentrations occur along the contacts between amphibolite and mica-quartz schist, within certain fe[s"ic gneisses, and in close association with iron formation units. This apparent lithologic association can be observed at many places throughout the study area but is best exemplified by two areas des~ribed below. Figure 19 shows the distribution of abandoned- mines associated With the Pumpkinvine Creek Formation and the adjacent rocks. Mines .are concentrated along the Barlow Gneiss Member of the Pumpkinvine Creek Formation and at several points along the Pumpkinvine Creek-Canton Formation contact. These lithologies and contacts probably served as important prospecting tools for the early miners, judging from the amount of activity associated with them here and in other areas. Anotable concentration of mines can be observed north of Auraria where open-cut and underground mining was confined to the Barlow Gneiss (fig. 20). This felsic gneiss was mined at the Barlow Cut Mine for a continuous distance of approximately 1 km (0.6 mi) along strike and in intermittent areas for several more kilometers at mines to the southwest and northeast. Assays published by Pardee and Park (1948) of cores taken in and adjacent to this gneiss showed high gold values confined almost entirely to this lithology. Another large concentration occurs along Findley Ridge at Dahlonega (fig. 21). Here, twelve mines are located along a sequence of rocks (igf, fig. 21) that lie between massive amphibolites of the Pumpkinvine Creek Formation and schists of the Canton Formation. Mines occur along the entire length of this sequence which consists of interlayered iron formation, biotite-plagioclase-quartz gneiss, sericite-quartz schist, and amphibolite and is interpreted to be part of the Pumpkinvine Creek Formation. Cook and Burneil (1983) also recognized this sequence and informally called it the Singleton formation. 17 Figure 18. Hydraulic mining near Auraria, Georgia (circa 1930). Photo courtesy of Georgia Department of Archives and History. 18 EXPLANATION Univeter Formation ~ Univeter Formation undifferentiated Canton Formation [TI Helen Member QU Chestatee Member [] Palmer Creek Member . ~ Proctor Creek Member and coarsely porphyroblastic facies (cp). Iamp I amphibolite ~ pyritic sericlte'quartz schist chlorite and/or hornblende Pumpkinvine Creek Formation [] Pumpkinvine Creek Formation undifferentiated []!] iron formation, metatuff, and amphibolite ~ Barlow Gneiss Member Rocks Northwest and Southeast of the Study Area Ipgs I Great Smoky Group ~Sandy Springs Group ~ amphibolite and schist Unassigned Intrusive Rocks [] biotit~ metatrondhjemite [] amphibole metatrondhjemite e28 mine location Figure 19. Relationship between abandoned gold mines and lithology-Auraria/Dahlonega area. 19 ;_-....... EXPLANATION Canton Formation ~ Palmer Creek Member ~ Proctor Creek Member and coarsely porphyroblastic facies (cp) amphibolite ~ pyritic sericite- quartz schist chlorite and/or hornblende Pumpkinvine Creek Formation ~ Pumpkinvine Creek Formation undifferentiated ~ Barlow Gneiss Member Unassigned Intrusive Rocks [_] biotite metatrondhjemite 50 mine 'location 0 0.5 Mile 0 500 Meters I I N Figure 20. Concentration of abandoned gold mines along the Barlow Gneiss Member. '20 Canton Formation ~ Palm\it Creek Member 1 I I ~ Proctor' Creel< Member and coarsely porphyr0 blastic facies (cp) amp amphibolite Pumpl 50% pyrite. 23 sequence of the Pumpkinvine Creek Formation. These finegrained clastics are now schists and gneisses of the Proctor Creek and Palmer Creek Members. Fine-grained clastic sedimentation was interrupted by extrusion of the Chestatee Member now consisting of interlayered amphibolites and felsic gneisses. The Chestatee Member was in turn followed by a repetitive sequence of shales and medium-to coarsegrained immature sandstones (or graywackes). This repetitive sequence, resembling part of a turbidite sequence, is now interlayered schist and metagraywacke of the Helen Member. Although the Proctor Creek, Palmer Creek, and Helen Members are predominantly sedimentary in origin, the sequence was punctuated by limited volcanic activity now represented by thin amphibolite units and iron formation. Deposition of the Univeter Formation followed deposition of the Helen Member and probably represents part of a volcanic-sedimentary cycle similarto the Pumpkinvine Creek and Canton Formations. Chemical analyses of amphibolites of the Pumpkinvine Creek and Univeter Formations in the study area reveal an abyssal tholeiite affinity, indicating formation on an oceanic ridge or in a back-arc basin (table 4, figs. 23, 24, 25). Although efforts to distinguish between lithologies formed in these two environments based solely on chemistry have been unsuccessful (Rogers, 1982), the occurrence in the study area of an enormous amount of metamorphosed immature sediments favors a back-arc basin environment. This conclusion also was favored by McConnell (1980) and McConnell and Abrams (1984) regarding the same formations southwest of the study area and by Burnell and Cook (1984) for metavolcanic rocks in the Dahlonega area. An interesting departure from the trend of abyssal tholeiite (back-arc basin) affinities is the island arc/active continental margin affinities of some Univeter Formation samples (figs. 24 and 25). The bimodal character is geographically controlled because samples BGE-3,. C-3, and DAH-7 were collected southwest of Dahlonega, whereas samples CL-12 and H-9 were collected northeast of Dahlonega. More geochemical data are needed on amphibolites of the Univeter Formation before an in-depth interpretation of its original tectonic setting can be made. Table 4. Major oxide and selected trace-element analyses of Pumpkinvine Creek and Univeter Formation amphibolites. Major Oxide M-21 Pumpkinvine Creek Formation M-2 JN-20 DV-33 DV-74 BGE-3 Univeter Formation :."'~, C-3 DAH-7 CL-12 H-9 .%Si02 47.7 47.5 45.5 47.5 47.1 %A120 3 14.7 13.7_ 14.6 13.8 14.0 52.4 48.3 58.3 46.0 48.7 15.4 17.2 14.4 16.8 : "'It~~ 16.8 ', % Fezo3 6.8 4.2 5.9 5.1 6.0 7.5 6.5 5.8 4.67 4.52 %Fe0 7.2 8.4 5.0 5.7 6.0 5.0 8.1 4.8 4.2 3.6 %Mg0 8.10 8.27 8.90 9.07 8.12 5.20 8.51 4.20 11.2 9.22': %Ca0 11.8 11.5 14.2 13.1 13.4 7.44 4.20 8.80 13.8 11.1 %Na20 2.17 1.91 1.78 1.89 1.76 3.31 2.77 1.87 1.97 2.32 %Kz0 0.13 0.10 0.11 0.095 0.13 0.11 0.088 0.15 0.31 0.87 %Ti02 2.24 1.85 1.49 1.36 1.49 . 1.30 1.55 0,65 0.77 0.40 %Mn0 0.18 0.21 0.18 0.20 0.18 0.24 0.20 0.18 0.16 0.16 % P20s 0.19 0.16 0.12 0.12 0.12 0.11 0.13 0.069 0.058 0.47 LOI 0.9 1.4 0.8 0.9 0.9 1.0 2.2 0.9 1.3 2.0 Total 102.1 99.2 98.58 98.8 99.2 99 99.7 100.1 101. 2 100.1 Trace Element ppmV 80 100 55 45 75 ppm Cr 65 50 350 350 280 ppm Ni 60 60 110 100 70 165 240 115 50 65 10 10 5 310 260 20 20 15 250 170 24 ,, ~ '' f i [,:: 10 9 8 x Unlveier Formation 7 Hhls study) ' 6 Pumpklnvlne creak Formation a Cthls study) 4 Abyssal. ~holellte o Pumpklnvlne Creek Formation (MoConnen, 1980) " field c Hlllabea Greenstone nun and others, 1978) 2 ,, .''> 300 :,, 200 Ti02 % 1 0.9 0.8 0.7 0.6 0.5 c 0.4 X 0.3 t' ,\ 0.2 \:, ,( Ni 100 90 ppm 8.0 70 60 50 11'1 : 40 30 L ,:-'> 20 '' ,;j 'i I ,. -r11:1 1'. '.I li unlveter Formation (this s,\~dy) PumpklnvlnEl Creek Formation (this studyJ 6 'P~tn_pklnvlne creek Formatliiri (McConnell, 1980) c Hlllabee Greenstone (Tull and others, 1978) . ,;: , "<---\---Field.ofvolcanlo rocks of- Island arcs and active co,n!lniintal"marglns X c 2 3 4 6 .6 7 ~eO* /M~dl Figure 23. . il Determination of amphibolite protolith based on a plot of FeO*/MgO versus percentage Ti02 (after Miyashiro ahd Shido, 1975). Pumpkinvine (:reek Formation data after McConn1=111 (1980) and Hillabee Greenstone data after lull and others (1978) are plotted for compari~oi-1: . . 2 3 4 FeO'J; MgO 6 7 .,FeO* ,. FeO + 0.9Fe20 8 Figure 24. . : ") Determinatiop of amphibolite protolith based on plot of FeO*/MgO versus pp'm Ni (after Miya- sliiroar;td Shido, 1975).Pumpkinvine Creek For- mation data after McConnell (1980) and Hillabee Greenstone data after lull and others (1978) are plotted for comparison. - l 25 1000 900 800 700 600 500 400 300 200 Cr ppm 100 90 80 70 60 50 40 30 20 x Univeter Formation (this study) Pumpkinvine Creek Formation (this study) o Pumpkinvine Creek Formation (McConnell, 1980) o Hillabee Greenstone CTull and others, 1978) Abyssal tholeiite field D Field of volcanic rooks of island arcs and active continental margins 10 L-----~~~2~~--3~----~4----~5----~6----~7 FeO*/MgO FeO'= FeO + 0.9 Fei03 Figure 25. Determination of amphibolite protolith based on a plot of FeO*/MgO versus ppm Cr (after Miyashiro and Shido, 1975). Pumpkinvine Creek Formation data after McConnell (1980) and Hillabee Greenstone data after lull and others (1978) are plotted for comparison. Accompanying the deposition of the Pumpkinvine Creek, Canton, and Univeter Formations in the study area was the deposition of volcanogenic gold and massive sulfides. Gold was deposited in all of these formations but was particularly concentrated within felsic volcanic rocks, in the vicirlity of iron formation, and along contacts between volcnic and sedimentary rocks, probably reflecting an exhalativE. :Jrigin in the vicinity of submarine volcanic vents. Venting :ilso was probably active during deposition of the sedimentary sequences of the Canton Formation since several of the gold deposits in this formation are not directly associated with metavolcanic rocks. During regional metamorphism and deformation the gold was remobilized and concentrated in quartz veins that are generally parallel to the regional foliation. Subsequent exposure and weathering of the gold deposits accounted for an apparent supergene enrichment. Massive sulfides that were deposited in rocks of the study area were confined to the Univeter Formation or along the Univeter-Canton Formation contact. The mineralogy and stratigraphic setting of these massive sulfide deposits are similar to the Besshi deposits described by Franklin and others (1981). Similar volcanogenic origins are expressed by McConnell and Abrams (1984) for gold and massive sulfide deposits in the Pumpkinvine Creek, Canton, and Univeter Formations southwest of the study area. At some point after their deposition, the lithologies in the study area were metamorphosed to staurolite-amphibolite grade and were deformed during three, possibly four, fold events of progressively lower intensity. Major faulting also accompanied folding and metamorphism. Field data suggest that the Shope Fork fault is the oldest fault in the study area. Movement along this fault was probably pre- to synmetamorphic. Movement along the Chattahoochee fault followed that of the Shope Fork fault and probably occurred at the peak or slightly after the peak of regional metamorphism, coinciding with the formation of the Auraria antiform (F1). The Allatoona fault truncated the Auraria antiform and, therefore, postdates the Chattahoochee fault and the peak of regional metamorphism. SUMMARY The rocks that constitute the Dahlonega gold belt consist of metamorphosed volcanic and sedimentary rocks of the Pumpkinvine Creek, Canton, and Univeter Formations. These rocks in the study area are a northeastward extension of the New Georgia Group defined by McConnell and Abrams (1984) in west-central Georgia. The Pumpkinvine Creek Formation, the structurally lowest unit in the sequence, is composed of metavolcanic rocks. The Canton Formation, a predominantly metasedimentary unit, overlies the Pumpkinvine Creek Formation, and is overlain in turn by the Univeter Formation, a predominantly metavolcanic unit similar to the Pumpkinvine Creek Formation. One member, the Barlow Gneiss Member, was identified within the Pumpkinvine Creek Formation, and four members, the Proctor Creek, Palmer Creek, Chestatee, and Helen Members, were identified within the Canton Formation. No new members were defined for the Univeter Formation. The protoliths of these three formations were deposited in a rapidly subsiding basin that had substantial volcanic and sedimentary components, as in a back-arc basin. These lithologies were metamorphosed to staurolite-amphibolite grade approximately 365-million years ago during regional metamorphism and were subjected to at least three fold events. The boundaries of the gold belt are largely defined by the pre- to synmetamorphic Shope Fork fault, the peak to post-peak metamorphic Chattahoochee fault, and the post-peak metamorphic Allatoona fault. GoJd deposition was originally syngenetic and is predominantly associated with iron formation, felsic gneisses, and rocks at or near the contacts between metavolcanic and metasedimentary sequences. During regional metamorphism and deformation gold was remobilized and concentrated in sulfidic quartz veins that largely conform to the foliation of the enclosing rock. In the study area the overall occurrence of gold is lithologically controlled, whereas its local concentrations in these rocks are controlled by small-scale structures (cleavages, folds, etc.). Erosion and weathering of gold" bearing rocks has accounted for a mechanical concentration of gold in placers and an apparent supergene enrichment in saprolite. 26 .'~M~f~~~1~fi~7~~~~-'}i~ti~~~!.'f\~W?"'~''P . ,. . r Abrtms, C.E., and McCoRnEnFelElR~EKN.Cl.,E-1S982, The relatio'nship~f!: Franklin, J.M., Lydon,J.W.,and Sangster, D.F., 1981, Volcanicassociated massive sulfide deposits: Economic G~ology '.-" : banded iron formati6nto mihesand prospectsotwestern Seventy-Fifth Anniversary Volume, p. 485-627. Georgia: Georg'ia G1E!ologicSurveyO!JenFlle Retmrt82- . Fripp, R.E.P., 1971.;,'. St.ratabound gold deposits in A(chean "$c(map), scale 1:100,000. ' , ,.. ,. , . band(:ld,.,iron Jorm i ' 1984, ' " "0 The ~ , i' : r geochemist'ryo( Hartley, M.E., Ill, 1976, Graves Mountain, in Chowns, T.M., 111etavoltanic rocks in theDahlonega District, Lumpk'i~' ed., Stratigraphy, structure, and seis,micity (11 Sl~te Belt County, Georgia: Geologic Society of America Abstracts . with Pr.ognims, v.16; no. 3, p. 127. _ . . _ 1 rocks along the Savannah River: Georgia Geqlogical Society Guidebook 16, p. 42-52. Carpenter, R;H.; 1982, Aluminosilicateassemblages: an e)the con- nr along a tributary tact between felsic of the Chestatee gneiss and amphibolite River and sever of the Chestatee Mem- al pits. ber and biotite-quartz, schist of the Palmer Creek Member. Chestatee 103 Lumpkin Copper Dahlonega .Seven inclined r. shafts. . !,' Oc<;:urs along th~ contact between amphibo1ite of the (J niveter Formation and interlayered garnet-biotite-muscovite-quartz schist and metagraywacke bf the Canton Formation. 1S92: 200 tonss; 1918-19: 48,835 tonss . Massive sulfid~ mine. Loud 104 White Cleveland ' Place'rWorking( Occul's'ak:>rig the con> along ToWn tattbetweenamphibo- Creek atid one lite, iron forrtiation, and of itstributaries. b iotite~rti hs<:dv ite- quartz schist df the Uni- veter Formation and interlayered garnet-bio- tite-muscovite-quartz. schist and metagray- wacke of the Helen iii Member. Old 105 White Cleveland Placerworkings, . Same as Loud Mine ' . ';-- ~ nr Ash bury along a tributary (#104). 6J Chateen Creek and four, . vertical shafts. Courtney 106 White Cleveland Placer workings along a 'tributary of Town Creek and several open cuts. Occurs within biotitequartz-pI ag iocl ase gneiss of .~he Sandy Springs Croup. nr Not located in gold belt litholo- ,gies. Henderson 107 White Cleveland Placer workings Occurs within biotite- nr along a tributary muscov'ite-quar(z schist of Tesnatee and amphibolite of the Creek. Univeter Formation. 37 Appendix (Cont'd) Mine Etries McAfee Atkinson Matthews Reaves No. County 108 White 109 White 110 White 111 White 112 White 7.5 minute quadrangle Type of workings Cleveland Placer workings along atributary of Glade Branch plus one open cut. Cleveland Placer workings along atributary of Jenny Creek plus three ad its. Cleveland Placer workings along atributary of jenny Creek plus several pits. Cleveland Placer workings along atributary ofTown Creek. Cleveland Geologic Setting Occurs within interlayered garnet-biotite-muscovite-quartz schist and metagraywacke of the Helen Member. Same as Etries Mine (#108). Same as Etries Mine (#108). Same as Etries Mine (#108). Sprague/ Blake 113 White longstreet 114 White Wyman 115 White Hood/Allen Bell 116 White Cox/Merritt 117 White Cowrock Cowrock Cowrock Cowrock Cow rock Placer workings along tributaries of jenny Creek, two adits, an open cut, and several pits. Placer working along Turner Creek and its tributaries, an open cut, and an adit. An indined shaft and a pit. One adit. One open cut. The placer workings occur within interlayered garnet-biotite-muscovite-quartz schist and metagraywacke of the Helen Member. Theremaining workings occur within and bordering a coarsely crystalline amphibolite. Occurs within interlayered garnet-biotitemuscovite-quartz schist, metagraywacke, and amphibolite of the Helen Member of the Canton Formation and iron formation, biotitepI agi oclase-q ua rtz gneiss, and amphibolite of the Univeter Formation. Occurs within garnetbiotite-muscovitequartz schist and metagraywacke of the Helen Member. Occurs within amphibolite of the Univeter Formation. Occurs within amphibolite of the Univeter Formation. Production nr nr nr nr nr nr nr nr nr nr Remarks Exact location unknown. 38 Appendix '(Cont'd) Mine No. County Castleberry 118 White Thurman 119 White White County/ Thompson 120 White Yonah/ Calhoun 121 White Diltz 122 White Reynolds/ 123 White Hamby St. George/ 124 White Dean Conley 125 White Plattsburg/ 126 White England 7.5 minute quadrangle Type of workings Cowrotk Helen Placer workings alohg Thurmond creek and ohe of its t'ributaries plus severfll pits.. Two adits and several pits. Helen Several pits. , Geologic Setting Occurs within interc layered garnet-biotitemuscovitequartz schist arid metagraywacke of the Helen Member. Occurs within amphibolite of the Univeter FOrmation. Occurs within biotite'pl ag iocl ase-q uartz gheiss of the Univeter FOrmation. Production nr nr nr Helen Helen Helen Helen Helen Helen Placer workings along Dukes Creek and its tributaries 'plus several open cuts. Workings occur over a Pre-1895:. large area within gar- 20,000-50,000 net-biotite-muscovite- oz.1 quartzschi~t, metagray- wacke, andamphibolite of the Heier\' Member; b iofite-pia'giocl asequartz gneiss and amphibolite of, the Uni~ veter Formation; and biotite gneiss of the Sandy Springs Group. Two adits. Occurs. within inter- nr layered biotite-plagio- .clase-quartz gneiss and amphibolite of the Univeter Formation. Placer workings Occurs within inter- nr alongtributari~s layered garnet-biotite- of Dukes Creek muscovite-quartz schist, and the Chatta- metagraywacke, and hoochee River, amphibolite of the several open Helen Member. cuts, pits and a d its. Placerworkings Occurs within inter- nr along tributaries layered garnet-biotite- of the Chatta- muscovite-quartz schist hoochee River, and metagraywacke of several open the Helen Member. cuts, and several ad its. nr Placer workings Same as St. George/ nr along a tributary D~an Mine (#124). of the Chatta- hoochee River. Remarks Mine property is now a subdivision. Extensive underground workings reported in the literature. Some of ,the: workings between Dukes Creek and. th~ town of Helen may be attributable to the Reynolds/ Hamby Mine. j! Exact location unknown. 39 Appendix (Cont'd) Mine Lot10 Childs Lumsden/ Jones Hood/ SoqueCiub Wilson No. County 127 White 128 White 129 White 7.5 minute quadrangle Type of workings Helen Several overlapping. open cuts. Helen Placer workings and an open cut along a tributary of Bean Creek. Helen Placer workings along Bean Creek and its tributaries. 130 Habersham Lake Burton 131 Habersham Lake Burton Geologic Setting Same as St. George/ Dean Mine (#124). Same as St. George/ Dean Mine (#124). Occurs within biotitemuscovite-quartz schist and amphibolite of the Univeter Formation and migmatitic biotite gneiss of the Sandy Springs Group. Brooks 132 Habersham Lake Burton Williams Kennedy Smith Stonesypher 133 Habersham Lake Burton Placerworkir:~gs along a tributary of Goshen Creek. 134 Habersham Lake Burton Placer workings along a tributary of Goshen Creek. 135 Rabun Lake Burton Placer workings along Dicks Creek. 136 Rabun Lake Burton Occurs within plagioclase-garnet-biotitemuscovite-quartz schist and amphibolite of the Univeter Formation. Occurs within amphibolite of the Univeter Formation. Occurs within amphibolite, plagioclase-biotite-quartz gneiss, and biotite-quartz schist of the Tallulah Falls Formation. Bartley/ Barclay 137 Rabun Moore Girls 138 Rabun Hightower Two adits, a Bald shaft, and sever- al pits. Dillard An open cut, an ad it, and several pits. Occurs within muscovite-biotite-quartz-piagioclase gneiss. of the Coweeta Group. Occurs within muscovite~biotite-quartz-pla gioclase gneiss of the Cmyeeta Group and amphibolite, biotitequartz schist, metagraywacke, and epidote quartzite ofthe Tallulah Falls Formation. 40 Production nr nr Remarks nr nr Exact location unknown. nr Exact location unknown. nr Exact location unknown. nr nr nr nr Exact location unknown. Probab- ly covered by Lake Burton. nr Located north- west of gold belt lithologies. nr \ \ Appendi:tt (d'ont'd)" 7.5 minute Type of '>'i Mine . No. County ''quadrangle ' 111/orkir'rgs Lot190 and 139 Rabun Dillard '"' . Plac~?rWqrkings o'c'durs witlli~ inter- nr 191 . along~t'ributary Fay'e1red' a'mph\bolite, of the Little Ten- biotite-quartz' schist, :. nessee:River: metagraywacke, and : ~. epidote quartzite of the Tallulah Falls Formation. ) I ,'' nr - not rec()rded I< 1 Yeates and others (1896) 2 )ones (1909) 3 Pardee and Park (1948) 4 Shearer and Hull (1918) s Kline and Be~~ (1949) ,.; ,;i''.' Remarks' 1;1,.r ~' I I ' '{ . ...-. ' ,- ; , ~ i i I' '"'' ...' 'I , ;:/ , i~ _.I ', I 41