Bedrock geologic map of the Marion West 7.5-minute quadrangle, McDowell County, North Carolina

North Carolina Geological Survey Open File Report 2020-07 CZIfs 82°0'0"W 35°45'0"N EXPLANATION OF MAP SYMBOLS CONTACTS Zone of Confidence: 300m Contact — Identity and existence certain, location accurate Contact — Identity and existence questionable, location approximate Strike-slip fault, right-lateral offset- Identity questionable, existence certain, and location accurate. Arrows show relative motion Contact — Identity and existence certain, location approximate Thrust fault (1 st option)/Strike-slip fault, right-lateral offset — Identity and existence certain, location approximate. Saw teeth on upper (tectonically higher plate). Arrows show relative motion Thrust fault (1 st option) — Identity and existence certain, location accurate. Saw teeth on upper (tectonically higher plate). PLANAR FEATURES (For multiple observations at one locality, symbols are joined at the "tail" ends of the strike lines) Inclined metamorphic or tectonic foliation — Showing strike and dip 7У 78^ Inclined metamorphic or tectonic foliation, for multiple observations at one locality — Showing strike and dip Vertical metamorphic or tectonic foliation — Showing strike Vertical mylonitic foliation — Showing strike Inclined mylonitic foliation — Showing strike and dip Vertical metamorphic or tectonic foliation, for multiple observations at one locality — Showing strike VS s Small, minor inclined joint — Showing strike and dip Small, minor inclined joint, for multiple observations at one locality — Showing strike and dip Small, minor vertical or near-vertical joint, for multiple observations at one locality — Showing strike Small minor vertical or near-vertical joint — Showing strike Inclined mylonitic foliation, for multiple observations at one locality — Showing strike and dip Vertical mylonitic foliation, for multiple observations at one locality — Showing strike Inclined generic foliation (origin not specified) — Showing strike and dip LINEAR FEATURES Inclined aligned-mineral lineation — Showing bearing and plunge -220.252 . ,8 Inclined slickenline, groove, or striation on fault / surface — Showing bearing and plunge я 66 Inclined fold hinge of generic (type or orientation unspecified) / small, minor fold — Showing bearing and plunge * Inclined generic (origin or type not known or not specified) lineation ^ or linear structure — Showing bearing and plunge OTHER FEATURES о Float station !06 A Thin section and whole rock analysis sample location X Prospect (pit or small open cut) X Abandoned sand, gravel, clay, or placer pit Abandoned open pit, quarry, or glory hole NATURAL RESOURCES MIC - Mica SDG - Sand and gravel STN C - Crushed stone STN F - Flagstone TLC - Talc WHOLE ROCK ICP ANALYSIS1 OF SELECTED SAMPLES ■216,252 SAMPLE2 19NB413 19NB402 19NB340 19NB210 19BC47a 19BC303 19BC316 19BC452 19BC171 19NB107 19BC116 19BC184 19BC42 19NB111 19NB216a COORDI 219.012N. 218.873N, 224,1 12N, 222.836N, 202.31 3N, 215.498N, 220,531 N. 223,291 N. 223.950N, 216.654N, 215.461N, 222.934N, 223.250N, 221.276N, 222.792N, NATES3 331 ,604E 330.719E 333.985E 333.691 E 320.190E 336.833E 335.540E 336.308E 337.363E 328.929E 329.276E 338.118E 330.496E 328.504E 333,931 E ROCK TYPE4 mylonite mylonite meta- arenite meta- arenite meta- aienite garnet - mica schist siliceous marble biolile granitic gneiss biotile granitic gneiss biotite gneiss biotite gneiss quartz monzonite granitoid ultramafic granitic orthogneiss MAP UNIT bzmp bzmp Cce Cce Cce Ztfs Ztfm Ztf Ztl Ztf ZII Ztf Ycu Ycu Ytc MAJOR OXIDES IN PERCENT Si02 65.88 61.52 88.88 84.99 87.59 56.06 32.33 66.46 69.08 59.09 64.4 72.64 56.32 46.5 76.49 ai2o3 15.06 17.85 4.9 7.49 5.63 20.7 10.26 15.41 13.95 18.38 15.7 13.92 18.23 14.9 12.68 Fe203 7.23 8.15 2.22 2.06 1.72 11.56 3.71 4.82 5.36 7.38 6.28 1.41 7.46 16.22 1.37 MgO 1.89 1.96 0.19 0.33 0.19 2.08 1.17 1.6 1.51 2.26 2 0.07 2.41 5.17 0.18 CaO 1.56 1.05 0.02 0.03 0.01 0.53 27.15 1.88 1.98 1.71 2.38 1.12 3.86 7.63 0.32 Na20 2.78 2.09 0.04 0.04 0.05 0.79 1.6 2.4 2.62 2.79 3.35 4.91 4.85 3.3 3.92 K20 1.92 2.84 2.65 2.83 2.9 4.48 2.23 2.31 2.11 4.79 3.46 4.75 3.16 0.99 4.47 Ti02 1.24 0.98 0.45 0.76 0.33 1.36 0.38 0.76 0.74 0.78 0.71 0.07 0.93 3.87 0.08 P205 0.15 0.12 0.01 0.02 0.03 0.11 0.17 0.21 0.18 0.21 0.19 0.02 0.42 0.38 0.02 MnO 0.13 0.13 0.01 0.01 <0.01 0.1 0.05 0.03 0.15 0.08 0.11 0.02 0.09 0.21 0.08 Cr203 0.008 0.01 0.003 0.002 <0.002 0.014 0.004 0.003 0.007 0.009 0.006 <0.002 0.004 0.008 <0.002 LOI5 1.9 3.1 0.5 1.2 1.5 1.7 20.5 3.9 2.1 2.2 1.2 0.7 1.9 0.5 0.3 SUM6 99.81 99.83 99.95 99.87 99.96 99.81 99.6 99.86 99.86 99.79 99.82 99.77 99.79 99.74 99.95 ELEMENTS IN PPM7 Ba 549 520 396 452 399 2563 390 509 660 1237 681 1263 1252 264 330 Ni 34 42 <20 <20 <20 33 <20 22 23 29 27 <20 <20 36 <20 Sc 14 17 3 4 3 24 9 8 14 16 12 <1 11 25 4 Be 5 1 <1 1 <1 3 <1 <1 <1 4 4 <1 3 <1 <1 Co 18.2 23.6 3.2 3.4 2.1 20.2 8 11 11.3 13.6 13.9 0.9 15.6 45.3 1.2 Cs 3.1 2.3 0.2 0.6 0.3 2.1 1.9 1.6 1.2 3.9 3.2 0.8 0.7 0.2 0.3 Ga 18.2 22.6 5.3 9.9 6.5 27.6 14.2 18.3 15.1 28.1 22.8 24.7 18.5 19.7 13.7 Hf 11.2 8.6 6.7 15.6 5.1 6.9 4 9.4 6.3 6.5 5.4 6.1 8.5 4.6 3.1 Nb 17.4 17.1 6.7 11.5 5.6 26.7 8.2 16.7 12.1 21.1 20.2 16.2 10.2 18.6 12.5 Rb 80.6 113.3 45.5 64 51.1 127.2 80.6 95.3 81.6 139.4 133.4 200.5 93.1 17.5 101 Sn 2 3 <1 1 <1 4 1 5 1 4 4 1 <1 2 <1 Sr 254.1 205.1 35.3 20.7 30.9 107.4 2507.6 201 202.9 301 282.9 164.8 516.9 467.9 104.7 Та 1.2 1.1 0.4 0.7 0.4 1.7 0.5 1.1 0.7 1.5 1.3 0.8 0.5 1 0.4 Th 10.4 13.6 6.1 12.4 4.5 15.1 6.9 6.4 9.7 16.2 13.5 43.7 1.9 1.7 10.5 U 2.1 2.6 1 1.9 1.6 3 3.5 1.1 1.1 4.8 3.4 12.6 0.8 0.4 5.2 V 110 90 19 39 23 151 34 77 79 82 74 9 91 228 <8 W 1.5 1.4 0.6 1.6 0.9 1.4 0.9 0.8 <0.5 2.8 4.6 <0.5 <0.5 <0.5 1.3 Zr 425.2 313.4 257.3 614.6 180.1 248 155.7 362.1 243.1 242.2 187 138.4 357.4 172.9 69.9 Y 40.5 30 8.4 35.9 8.6 50.2 30.9 14.2 52.9 53.3 45 10.4 20.2 29.1 39.3 La 39.6 25.9 13.7 53.9 14.4 74.3 50 19.5 70 81.4 65.8 315.8 42.2 19.9 14.5 Ce 78.4 44.4 26.9 81.2 25.4 154.1 99.8 27.8 37.2 165.3 129.1 524.9 82.9 43.6 31 Pr 10.24 6.92 3.42 14.37 3 17.57 11.72 3.97 14.24 18.8 15.33 52.03 9.66 5.9 3.63 Nd 37.7 25.9 14.3 55.8 12.3 67.2 45.5 14.1 55.2 70.9 58.3 171.8 40.8 27.2 14.1 Sm 8.15 5.2 2.71 10.71 2.56 12.37 8.49 3.27 10.8 13.32 11.08 17.11 7.1 6.16 4.45 Eu 1.66 0.98 0.42 2.39 0.52 2.22 1.4 1.08 2.21 2.13 1.8 3.34 2.25 1.97 0.3 Gd 7.35 4.28 2.07 8.5 1.88 11.16 7.38 3.16 10.53 11.84 9.72 6.82 5.91 6.45 5.13 Tb 1.2 0.7 0.27 1.22 0.26 1.67 1.05 0.5 1.54 1.74 1.48 0.5 0.75 0.96 0.96 Dy 7.23 4.83 1.61 6.94 1.74 9.82 6.06 2.9 9.76 10.31 8.57 1.62 3.77 5.79 6.29 Ho 1.59 1.15 0.29 1.38 0.31 1.94 1.15 0.53 2.07 1.96 1.66 0.16 0.75 1.15 1.31 Er 4.73 3.93 0.82 3.92 1.06 5.51 3.2 1.46 6.51 5.63 4.74 0.27 2.01 3.11 3.88 Tm 0.69 0.6 0.12 0.57 0.14 0.77 0.4 0.19 0.96 0.78 0.64 0.06 0.27 0.42 0.59 Yb 4.35 4.06 0.92 3.89 1.11 4.89 2.55 1.26 6.74 4.98 4.02 0.52 1.82 2.7 4 Lu 0.69 0.62 0.14 0.53 0.18 0.72 0.38 0.19 1.02 0.77 0.63 0.07 0.27 0.42 0.58 Mo 0.3 0.3 3.4 0.2 1.3 1.1 0.9 0.5 0.4 0.6 1.3 1.4 0.3 1.7 1.3 Cu 28.7 10.1 6.7 3.6 2.8 26.3 13.2 21.2 8.8 21.7 32.9 13.9 24 16.9 2.9 Pb 3.2 3.2 1.5 1.5 2.1 2.9 8.2 8.5 5.2 2 8.1 254.6 4.1 1.6 3.8 Zn 92 113 5 3 2 64 56 104 60 121 130 44 81 68 6 Ni 29.9 42.8 6.2 2.8 3.6 35.1 12.6 19.5 24.6 29.7 26.9 2.7 7.4 19.5 2.3 As <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 <0.5 <0.5 1.3 <0.5 <0.5 <0.5 Cd <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.3 <0.1 <0.1 <0.1 Sb <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.2 <0.1 <0.1 <0.1 Bi <0.1 0.2 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 5.9 <0.1 <0.1 <0.1 Ag <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 1 <0.1 <0.1 <0.1 Au 0.7 0.6 <0.5 <0.5 <0.5 1.1 0.9 0.6 <0.5 <0.5 <0.5 0.8 <0.5 <0.5 <0.5 Hg <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 Tl <0.1 <0.1 <0.1 <0.1 <0.1 0.4 0.5 0.5 0.4 0.7 0.8 0.2 0.4 <0.1 <0.1 Se <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 <0.5 <0.5 <0.5 €Ztf Imagery . NAIP, June 2014 Roads . U.S. Census Bureau, 2015 - 2016 Roads within US Forest Service Lands . FSTopo Data with limited Forest Service updates, 2012 - 2016 Names . GNIS, 2016 Hydrography . National Hydrography Dataset, 2014 Contours . National Elevation Dataset, 2008 Boundaries . Multiple sources; see metadata file 1972 - 2016 Wetlands . FWS National Wetlands Inventory 1977 - 2014 UTM GRID AND 2016 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET U.S. National Grid 100,000*1»» Square ID “00 LV MV Grid Zone Designation 17S 1 Celo 2 Little Switzerland 3 Ashford 4 Old Fort 5 Marion East 6 Moffitt Hill 7 Sugar Hill 8 Glenwood ADJOINING QUADRANGLES Check with local Forest Service unit for current travel conditions and restrictions. MARION WEST, NC 2016 1 2 3 4 5 6 7 8 North Carolina Department of Environmental Quality Divison of Energy, Mineral and Land Resources Brian Wrenn, Director Kenneth B. Taylor, State Geologist CORRELATION OF MAP UNITS bzmp Mylonite / phyllonite INTRODUCTION The Marion West 7.5-minute quadrangle lies in McDowell county, western North Carolina. Within the quadrangle are the city of Marion and the smaller communities of Providence, Pleasant Gardens, and Garden Creek. Interstate 40, U.S. Routes 70 and 221, and N.C. Highways 226 and 80 are the major transportation corridors on the quadrangle. Major water features include Lake Tahoma, Catawba River, and Buck Creek. Total elevation relief is 1,924 feet with a low of 1,195 feet along the Catawba River and a high of 3,119 feet at Greenlee Mountain. A significant portion of the quadrangle is located along the Blue Ridge escarpment, the steep transition zone between the mountain and piedmont physiographic provinces. Dpg Porphyroclastic biotite gneiss Chilhowee Group Cce Quartzite Tallulah Falls Formation Undivided CZtfs schist CZtf CZtfm marble CZtfa amphibolite ultramafic bodies СЛ r— 4- -3 a IQ § £ 5 <L a о cn Alligator Back Metamorphic Suite Zabss Metasandstone Ytc Toms Creek granitic orthogneiss Mixed pegmatite and amphibolite Cranberry Gneiss undivided GEOLOGIC OVERVIEW Bedrock of the Marion West quadrangle is composed of units within five thrust sheets (from structurally highest to lowest): Fries/Spruce Pine, eastern Tugaloo, Fork Ridge, Table Rock, and Wilson Creek. The Table Rock and Wilson Creek thrust sheets comprise the Grandfather Mountain window, a tectonic window overlain by the Blue Ridge-Piedmont Megathrust that contains the upper thrust sheets exposed on the quadrangle (Fries/Spruce Pine, eastern Tugaloo, and Fork Ridge). Brief descriptions of the units within these thrust sheets are given below, beginning in the northwest corner of the map and proceeding to the southeast. FRIES/SPRUCE PINE THRUST SHEET The Fries/Spruce Pine thrust sheet is part of the western Tugaloo terrane. This thrust sheet contains Neoproterozoic metasedimentary and mafic rocks of the Ashe and Alligator Back Metamorphic Suites. These rocks are thick sequences of complexly deformed and metamorphosed clastic sediments deposited in marine rift basins. Interspersed with these sediments are lesser amounts of mafic volcanic rocks and ultramafic rocks thought to have originated as oceanic crust at a spreading center (Misra and Conte, 1991; Raymond and Abbott, 1997). These metasedimentary lithologies were complexly deformed and metamorphosed to amphibolite facies conditions during Taconic orogenesis. Rocks of the Spruce Pine thrust sheet are structurally above the Fork Ridge thrust sheet. Field data from the Marion West quadrangle indicate that this contact is overturned toward the northwest in this area. FORK RIDGE THRUST SHEET On the Marion West quadrangle the Fork Ridge thrust sheet is comprised of the Cranberry granitic gneiss and, tentatively, the porphyroclastic biotite gneiss unit. Extensive mylonitization obscures contact relationships but the porphyroclastic biotite gneiss unit is interpreted to intrude the Ashe Metamorphic Suite on the adjoining Old Fort quadrangle and, possibly, Mesoproterozoic basement gneisses on the Marion West quadrangle. A preliminary age date of 360 Ma for the porphyroclastic biotite gneiss (R. McAleer, March 2020, personal communication) is intriguing as Paleozoic intrusions into the Mesoproterozoic basement have not previously been reported for this area. The Cranberry gneiss undivided unit on the Marion West quadrangle is primarily a granitic orthogneiss with lesser amounts of biotite granitic gneiss and amphibolite. It is exposed NW of the Linville Falls fault and is interpreted to be Mesoproterozoic in age (Bryant and Reed, 1970). Lesser amounts of chlorite and muscovite within the unit differentiate it from the Toms Creek granitic orthogneiss on the quadrangle. The Fork Ridge thrust sheet and the underlying Grandfather Mountain Window are separated by the Linville Falls fault, an Alleghanian greenschist-facies ductile thrust fault (Van Camp and Fullagar, 1982). GRANDFATHER MOUNTAIN WINDOW The Grandfather Mountain Window is cored by Mesoproterozoic basement gneisses. These gneisses are overlain by the Table Rock thrust sheet. The Grandfather Mountain Window is framed by the Linville Falls fault. TABLEROCK THRUST SHEET Cambrian-aged quartzites of the Chilhowee Group represent a rift-to-drift transition during the opening of the lapetus Ocean basin (Hatcher and others, 2007). On the Marion West quadrangle the quartzite occurs as several small mylonitic slices along the Linville Falls fault and one large body in contact with the Toms Creek granitic orthogneiss along the Tablerock thrust fault (Bryant and Reed, 1970; Conley and Drummond, 1981). WILSON CREEK BASEMENT THRUST SHEET This is an informally named thrust sheet that constitutes the lowest structural area on the quadrangle. The Toms Creek granitic gneiss unit is of unknown age and is informally named after an undeformed core of granitic orthogneiss in the Johnson Paving Co. Inc. quarry along Toms Creek. Most of the unit is strongly mylonitic, only recognizable by pink potassium-feldspar layers and plentiful chlorite and muscovite. The Toms Creek gneiss is a subunit within the Mesoproterozoic Wilson Creek gneiss mapped by Bryant and Reed (1970). BREVARD ZONE The Linville Falls fault framing the Grandfather Mountain Window is cut by the Brevard Zone, a prominent NE-SW-striking feature. The Brevard Zone is a linear fault zone that extends from Alabama to Virginia. It has a complex history of multiple reactivations with the earliest movement during the Neoacadian orogeny. This first movement was ductile and high-temperature with an oblique to strike-slip motion. During the Alleghanian orogeny, the Brevard fault reactivated with ductile strike-slip motion reaching greenschist-facies conditions, and later, experienced brittle dip-slip motion (Hatcher and others, 2007). On the Marion West quadrangle the mylonite/phyllonite unit of the Brevard Zone is comprised of rocks that have been extremely mylonitized. The mylonitization makes protoiith recognition very difficult and the mylonite/phyllonite zone likely contains panels of both Toms Creek gneiss and Tallulah Falls metasediments. EASTERN TUGALOO TERRANE Lying southeast of the Brevard Zone, the Tallulah Falls Formation consists of meta¬ sedimentary and meta-igneous rocks interpreted to have been deposited in a distal marine basin outboard of the Laurentian rifted margin (Hatcher and others, 2007). TFF rocks on the quadrangle have been metamorphosed to upper amphibolite facies and are migmatitic. Mylonitic and non-mylonitic foliations within the quadrangle dominantly strike NE- SW and dip moderately to the SE. The prominent fracture set strikes NW-SE and is steeply dipping. A minor fracture set strikes NE-SW and is moderately to steeply dipping. Ytc CZtfm You mpa CZtfs bzmp Cce Zabss CZtfs AREA STEREONET DATA SCHMIDT EQUAL Bryant, B. and Reed, J.C., Jr., 1970, Geology of the Grandfather Mountain window and vicinity, North Carolina and Tennessee: U.S. Geological Survey Professional Paper 61 5, 190 p. map scale 1:62,500. Cardozo, N., and Allmendinger, R.W., 2013, Spherical Projections with OSXStereonet: Computers & Geosciences, v. 51, p. 193-205, doi:10.101 6/j.cageo. 201 2.07.021 . Conley, J.F. and Drummond, K.M., 1981, Geologic map and mineral resource summary of the northeast 1/4 Marion quadrangle, North Carolina: North Carolina Geological Survey, Geologic Map - 7.5-minute quadrangle maps and mineral resource summary GM 210-NE, scale 1:24,000. Hatcher, R.D., Jr., Bream, B.R., and Merschat, A.J., 2007, Tectonic map of the southern and central Appalachians: A tale of three orogens and a complete Wilson cycle, in Hatcher, R.D., Jr., Carlson, M.P, McBride, J.H., and Martinez Catalan, J.R., eds., 4-D Framework of Continental Crust: Geological Society of America Memoir 200, p. 595-632, doi: 10.1130/2007.1200(29). McAleer, R., 2020, USGS, personal communication. Misra, K.C. and Conte, J.A., 1991, Amphibolites of the Ashe and Alligator Back Formations, North Carolina: Geological Society of America Bulletin, v. 103, p. 737-750. Raymond, L.A. and Abbott, R.N., 1997, Petrology and tectonic significance of ultramafic rocks near the Grandfather Mountain Window in the Blue Ridge belt, Toe terrane, western Piedmont, North Carolina, In: Paleozoic Structure, Metamorphism, and Tectonics of the Blue Ridge of Western North Carolina, Carolina Geological Society Field Trip Guidebook, p. 67-85. 3000 Ф 2000 Li- 1000 Sea Level Unit Contact Fault Contact Linville Falls fault m Brevard '± q - - fault _ CZtfm ч '■"•4 ч VLV44 444 4V4 V ч ч 4 ^ X \ \\\\\\\ \ \ XWWWN^ \44N44s4X^Y \ \ \ _ \ \ \ \^>Л\у\ \ \ \\\\S4s^>,44 s. eztt 3000 2000 1000 Sea Level arrows indicate relative motion along fault T indicates motion toward viewer A indicates motion away from viewer p .. _ interpretive patterns of subsurface foliation orientations rOrm Lln6S based upon surficial structural measurements Van Camp, S.G. and Fullagar, P.D., 1982, Rb-Sr whole-rock ages of mylonites from the Blue Ridge and Brevard zone of North Carolina, in: Geoloqical Society of America Abstracts with Proqrams, v. 14, no. 1-2, p. 92-93. NORTH CAROLINA Department of Environmental Quality Research supported by the U.S. Geological Survey, National Cooperative Geologic Mapping Program under STATEMAP (award number G19AC00235, 2019). The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. Bedrock Geologic Map of the Marion West 7.5-minute Quadrangle, McDowell County, North Carolina By Bart L. Cattanach, G. Nicholas Bozdog, and Sierra J. Isard This is an Open-File Map. It has been reviewed internally for conformity with North Carolina Geological Survey mapping standards and with the North American Stratigraphic Code. Further revisions or corrections to this Open File map may occur. Some station data omitted from map to improve readability. Please contact the North Carolina Geological Survey for complete observation and thin-section data. Geology mapped from July 2019 to June 2020. Map preparation, digital cartography and editing by G. Nicholas Bozdog, Bart L. Cattanach, and Sierra J. Isard 2020 This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program. Contoured poles to joints and unidirectional rose diagram inset. Joint count 595. Bearing and plunge of fold hinges in blue and mineral lineations in red. Fold hinge count 16. Mineral lineation count 14. REFERENCES Contoured poles to foliation. Foliation count 406. Allmendinger, R.W., Cardozo, N., and Fisher, D., 2012, Structural geology algorithms: Vectors and tensors in structural geology; Cambridge University Press. 330,763 SCALE 1:24 000 1 0.5 0 KILOMETERS 1 2 1000 500 0 METERS 1000 2000 1 0.5 0 1 MILES 1000 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 FEET CONTOUR INTERVAL 40 FEET NORTH AMERICAN VERTICAL DATUM OF 1988 This map was produced to conform with the National Geospatial Program US Topo Product Standard, 2011. A metadata file associated with this product is draft version 0.6.19 ’Whole Rock Inductively Coupled Plasma - Atomic Emission/Mass Spectrometer analysis conducted by Bureau Veritas, 9050 Shaughnessy St, Vancouver, BC Canada V6P 6E5. 2Sample numbers correspond to thin section and whole rock sample localities shown on geologic map 3State Plane Coordinate System 4LOI = loss on ignition in percent 5SUM = Sum total in percent 6PPM = parts per million. Ni analyzed by Bureau Veritas LF200 and AQ200 procedures. 334,763 д. 35°37'30"N 82°0'0"W 82°7'30"W 35°45'0"N A DESCRIPTION OF MAP UNITS1 Mylonite/phyllonite — Intensely deformed rocks with unknown protoliths. Tan to light-gray to dark-gray to light-olive-gray, to greenish-gray; fine- to coarse-grained; lepidoblastic to porphyroblastic; strongly foliated; mylonitic, locally ultramylonitic, locally brecciated; consists of sericite, quartz, feldspar, biotite, chlorite, and accessory graphite, garnet, sulfides, magnetite, and opaque minerals. Lenticular muscovite-aggregate porphyroblasts flattened in the mylonitic foliation planes impart a distinctive "fish scale" or "button" appearance to phyllonites. Locally interlayered with porphyroclastic biotite gneiss, granitic orthogneiss, and felsic gneiss. Metasedimentary Rocks 224,252- Chilhowee Group Quartzite — White, fine- to medium-grained; thin- to thick-bedded; consists of about >85% quartz, 10% muscovite-sericite, 1-3% plagioclase, and traces of apatite, zircon, epidote group minerals, and titanite. 35°37'30"N 326,763 82°7'30"W Topographic base produced by the United States Geological Survey. Altered by the North Carolina Geological Survey for use with this map. North American Datum of 1983 (NAD83) World Geodetic System of 1984 (WGS84). Projection and Projection: State Plane North Carolina FIPS 3200 (Meters) 4,000-meter ticks: State Plane North Carolina FIPS 3200 (Meters) MN L 6‘ 54' 123 "MILS " 0‘ 37' 11 MILS ROAD CLASSIFICATION QUADRANGLE LOCATION Expressway Secondary Hwy Ramp Local Connector Local Road 4WD I Interstate Route [ — j FS Primary Route US Route FS Passenger Route О State Route FS High Clearance Route TRAVERSE MAP Hillshade derived from a six meter pixel resolution LiDAR (Light Detecting And Ranging) digital elevation model. Red lines show paths of field traverses. Tallulah Falls Formation (TFF) Undivided — Heterogeneous unit consisting of biotite gneiss interlayered with lesser amounts of metagraywacke, schistose metagraywacke, mica schist, metasandstone, amphibolite, felsic gneiss, and altered ultramafic bodies. Biotite gneiss is typically gray to grayish-black; medium- to coarse-grained; well foliated; compositionally layered; locally protomylonitic; inequigranular; locally porphyroblastic to lepidoblastic; migmatitic; consists of plagioclase, quartz, biotite, potassium feldspar, muscovite, garnet, epidote group minerals, chlorite, and opaque minerals. Commonly interlayered with other TFF lithologies. Metagraywacke — Medium-light-gray to medium-dark-gray; medium- to coarse-grained; foliated (ranges from massive to gneissic); equigranular to inequigranular; granoblastic to lepidoblastic; migmatitic; consists of quartz, plagioclase, biotite, muscovite, potassium feldspar, and minor garnet, opaque minerals, epidote, and apatite; thickness of layering ranges from decimeters to meters. Interlayered at all scales with other TFF lithologies. Garnet-Mica schist — Very light-gray to greenish-gray to medium-gray; fine- to coarse¬ grained; strongly foliated; inequigranular; lepidoblastic to porphyroblastic; locally migmatitic; consists of approximately 50% muscovite, 35% quartz, 5% biotite, 5% garnet, 2% plagioclase feldspar, and trace opaque minerals; interlayered with other TFF lithologies. Marble — Medium to dark gray; fine- to medium-grained; non- to weakly foliated; equigranular, granoblastic; consists of approximately 70% calcite and/or dolomite, 13% plagioclase, 12% quartz, 4% potassium feldspar and 1% muscovite. Amphibolite — Amphibolite is typically mottled white to dark-green to black; fine- to coarse¬ grained; foliated; equigranular to nematoblastic; consists of hornblende, plagioclase, biotite, epidote group minerals, quartz, and minor garnet, chlorite, pyroxene, titanite, and opaque minerals. Commonly interlayered with other TFF lithologies. Ultramafic bodies — Dark-green to silvery-grayish-green; fine- to medium-grained; non- foliated to strongly foliated; equigranular; granoblastic to nematoblastic to lepidoblastic; consists of tremolite/actinolite, relict pyroxene, hornblende, chlorite, talc, serpentine, relict olivine, opaque minerals, plagioclase feldspar, magnetite, spinel, and other accessory minerals. Compositions of altered ultramafic bodies are variable and mineralogical variations could not be mapped at a 1:24,000 scale. Alligator Back Metamorphic Suite Metasandstone — Interlayered metamorphosed sandstones with compositions including arkosic arenite, biotite-bearing metawacke, and quartzite. Tan to medium-gray to light-green; fine- to medium-grained; foliated to locally mylonitic; equigranular to inequigranular; consists of quartz, feldspar, muscovite, biotite, and minor accessory minerals; notably contains little schist, amphibolite, or garnet. Meta-igneous Rocks Porphyroclastic biotite gneiss — Heterogeneous mix of porphyroclastic and porphyroblastic, mylonitic biotite gneiss, quartzo-feldspathic gneiss, granitic orthogneiss, felsic gneiss, phyllonite, mylonite, and amphibolite, with minor biotite metawacke and metasandstone. Biotite gneiss is typically light-gray to grayish-black; well foliated; locally protomylonitic to ultramylonitic; medium- to coarse-grained; inequigranular; 2-10 mm sized porphyroblasts and/or porphyroclasts; lepidoblastic; consists of quartz, plagioclase, biotite, potassium feldspar, muscovite, minor epidote, garnet, and titanite. Radiometric age date of approximately 360 Ma (McAleer, personal communication, 2020). Toms Creek granitic orthogneiss — Semi-massive variety is coarse grained and equigranular with little chlorite and muscovite; mylonitic variety is fine- to medium-grained and equigranular with alternating pink potassium feldspar layers with silver-green chlorite-muscovite layers; both varities consist of potassium feldspar, quartz, plagioclase, muscovite, chlorite, and sericite; may contain small mafic/chloritic pods. Pegmatite and amphibolite — Heterogeneous mix of pegmatite, amphibolite, altered ultramafic rocks, and minor amounts of biotite gneiss; Unit present along contact of Cranberry Gneiss and metasandstone. Pegmatite — White to light gray to light pink; coarse-grained; granoblastic; consists of quartz, plagioclase, potassium feldspar, muscovite, biotite, and minor amounts of opaque minerals and garnet. Cranberry Gneiss undivided — Granitic orthogneiss with minor amounts of biotite gneiss; white to light pink; medium- to coarse-grained; equigranular to inequigranular; mylonitic to protomylonitic; consists of quartz, plagioclase, potassium feldspar, muscovite, biotite, and minor amounts of opaque minerals, epidote, chlorite, and garnet. ‘Mineral abundances are listed in decreasing order of abundance based upon visual estimates of hand samples and thin-secb'ons. Marion West 7.5-minute Quadrangle, Open File Report 2020-07