Bedrock geologic map of the Craggy Pinnacle 7.5-minute Quadrangle, North Carolina

NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES Tracy E. Davis, Director Dr. Kenneth B. Taylor, State Geologist О О N О Ш -I < О. о о N О ОС ш I- о ос о. ш MAP UNITS Trondhjemite Pzmg Migmatite ROCK DESCRIPTIONS1 Intrusives Ashe Metamorphic Suite/Tallulah Falls Formation Metagraywacke Zag Zagsi Zas Schistose metagraywacke Garnet mica schist Zaa Zua Amphibolite Altered ultramafic ПЗ o3 о (/> £= О аз go о Cl E 00 Trondhjemite - Very-light-gray to yellowish-gray; typically non-foliated; fine- to medium-grained; equigranular to inequigranular; typically granoblastic to megacrystic; occurs as thin dikes and sills ranging in thickness from centimeters to meters. Trondhjemites in the Asheville area have been age-dated at approximately 420 million years (Miller, 1998). Too small to be mapped at 1 :24,000 scale. Migmatite (Pzmg) - White to very-light-gray; non-foliated to weakly foliated; medium- to coarse-grained; equigranular; granoblastic; occurs commonly as thin layers and lenses (thickness of layering ranges from centimeters to meters) within other rock types and mappable bodies; locally gradational with pegmatite; consists of plagioclase feldspar, potassium feldspar, quartz, muscovite and sericite, and biotite. Migmatite (neosome) was most likely derived from local melting during regional high-grade metamorphism. Ashe Metamorphic Suite/Tallulah Falls Formation Metagraywacke (Zag) - Medium-light-gray to medium-dark-gray; non-foliated to weakly foliated (ranges from massive to gneissic to schistose); medium- to coarse-grained; equigranular to inequigranular; granoblastic to lepidoblastic; locally migmatitic; consists of plagioclase, quartz, biotite, muscovite, kyanite, sillimanite, opaques, epidote and apatite; thickness of layering ranges from several decimeters to several meters. Interlayered at all scales with garnet-mica schist, conglomeratic metagraywacke, amphibolite, and minor calc-silicate. Schistose metagraywacke (Zagsi) - Medium-gray to dark-gray; foliated to non-foliated; fine- to medium-grained; equigranular to inequigranular; lepidoblastic to weakly granoblastic to porphyroblastic; locally migmatitic; consists of quartz, plagioclase, muscovite, biotite, kyanite, sillimanite, epidote, chlorite, and trace opaque minerals; thickness of layering ranges from several millimeters to several centimeters to several meters; commonly interlayered with metagraywacke, garnet-mica schist, conglomeratic metagraywacke, amphibolite, and minor calc-silicate. Garnet mica schist (Zas) - Silvery-gray to medium-dark-gray; fine to medium grained; inequigranular; lepidoblastic and porphyroblastic; consists mostly of muscovite, biotite, garnet, and feldspar with trace amounts of epidote, chlorite, and opaques. Locally migmatitic. Interlayered with metagraywacke, schistose metagraywacke, amphibolite, altered ultramafics, and rare calc-silicate gran of els. Amphibolite (Zaa) - Amphibolite occurs as a minor rock type throughout other map units and as small mappable bodies: dark-green to black; fine to coarse grained; equigranular to nematoblastic; strongly foliated; consists of hornblende, plagioclase, quartz, epidote group minerals, garnet, chlorite, and minor relict pyroxene, titanite, and opaques. Altered ultramafic (Zua) - Dark-green to silvery-grayish green; non-foliated to strongly foliated; fine- to medium-grained; equigranular; nematoblastic to lepidoblastic; consists of 0 to 97% hornblende, 0 to 75% chlorite, 0 to 45% talc, 0 to 33% tremolite/actinolite, 0 to 19% serpentine, 0 to 15% relict olivine, 2 to 6% opaques, 0 to 1% plagioclase. These mineralogic variations could not be mapped at 1 :24,000 scale. Amphibolite within this unit occurs as a metamorphic alteration of the ultramafic or mafic rock. Thickness of the amphibolitic alteration is variable. Contains inclusions of other variations of altered mafic and ultramafic rock. Mineral percentages are based on visual estimates of selected samples. SCHMIDT EQUAL AREA STEREONET DATA + T rend and plunge of minor fold axes, n = 66 + Trend and plunge of mineral lineations. n = 30 + Poles to foliations, n = 936 . — 3) + Poles to joints with unidirectional Rose diagram inset, n = 839 WHOLE ROCK ICP ANALYSIS1 OF SELECTED SAMPLES 82°30 This geologic map was funded in part by the USGS National Cooperative Geologic Mapping Program 27' 30" 25' NORTH CAROLINA GEOLOGICAL SURVEY OPEN FILE MAP 2012-06 35°45' 27'30" 82°22'30" SAMPLE2 COORDINATES (State Plane NAD 83 m) ROCK TYPE MAP UNIT Si02 AI203 Fe203 OXIDES IN PERCENT MqO CaO Na20 K20 ТЮ2 P205 MnO О "1 ro 0 w Ba Cu ELEMENTS IN PPM3 Zn Ni Co Sr Zr Ce Y Nb Sc LOI4 SUM 5 BC43 213,853N; 294,577E calc-silicate Zagsi 69.74 11.62 4.62 2.82 4.84 0.76 0.49 0.8 0.16 0.14 0.016 269 17 61 <20 <20 133 483 44 44 12 9 3.8 99.96 BC66 214,707N; 297,059E metagraywacke Zags 76.15 9.87 4.94 1.47 0.96 1.35 3.1 0.88 0.1 0.08 0.014 1029 <5 55 <20 <20 190 491 67 29 11 9 0.8 99.98 BC181 218.914N; 294.278E ultramylonite Zas 61.32 19 6.12 1.33 0.03 0.37 3.38 1.17 0.07 0.21 0.01 981 35 110 <20 <20 90 354 98 31 22 16 6.7 99.96 BC391 218,358N; 300,834E kyanite, garnet, schistose metagraywacke Zagsi 43.78 26.69 12.3 4.91 1.97 2.66 3.34 1.45 0.07 0.19 0.024 960 74 213 41 30 260 264 96 44 10 24 2.2 99.88 BC432A 214,921N; 302,460E metagabbro Zua 48.61 15.2 14.13 5.99 9.57 3.38 0.09 1.5 0.13 0.23 0.032 20 24 121 28 34 148 73 <30 31 <5 53 0.9 99.86 BC432B 214,921N; 302,460E alterered olivine pyroxenite Zua 43.57 10.72 13.22 21.5 7.85 0.5 0.1 0.55 0.04 0.19 0.235 27 116 97 1076 103 35 30 <30 10 <5 19 0.9 99.63 BC433 214.991N; 302,438E alterered olivine pyroxenite Zua 42.74 12.13 15.26 21.2 5.95 0.77 0.1 0.81 0.06 0.22 0.134 40 12 110 842 104 24 44 <30 16 <5 23 0.1 99.61 BC435 215,024N; 302,401E talc, amphibole, serpentine schist Zua 39.66 12.92 15.58 18.7 5.04 0.73 0.16 0.86 0.06 0.22 0.132 16 7 127 790 96 28 50 <30 33 <5 25 5.5 99.67 BC469 219.094N; 296,850E metagraywacke Zag 83.53 7.19 2.62 0.73 0.45 0.89 3.26 0.6 0.06 0.03 0.003 704 9 27 <20 <20 96 425 <30 17 10 4 0.5 100.01 RW37 213,637N; 299,084E metaconglomerate Zag 79.39 8.76 3.32 0.9 0.51 1.26 3.94 0.59 0.31 0.07 0.004 1134 9 42 23 <20 121 328 65 42 15 7 0.7 100 RW47 216,594N; 295,356E kyanite, garnet, mica schist Zas 39.22 32.49 15.44 4.41 1.5 1.41 1.56 1.5 0.06 0.55 0.016 612 58 108 60 41 226 461 274 138 33 42 1.5 99.9 RW144 218,867N; 293,706E migmatitic metagraywacke Zag 68.36 14.53 4.73 1.55 1.91 3.33 3.82 0.64 0.2 0.07 0.01 1023 <5 57 <20 <20 362 358 70 19 14 11 0.6 99.98 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 1 984 (WGS84). Projection: Universal Transverse Mercator, Zone 17S 1 0 000-foot ticks: North Carolina Coordinate System of 1 983 Roads . ©2006-2010 Tele Atlas Roads within US Forest Service Lands . FSTopo Data with limited Forest Service updates, 2009 Names . GNIS, 2010 Hydrography . National Hydrography Dataset 2009 Contours . National Elevation Dataset 2008 MN i° 20 • \ 113 MILS 0° 50 SCALE 1 :24 000 ROAD CLASSIFICATION 1 Q5 0 KILOMETERS 1 2 10CO 500 0 METERS 10X) 2oco 1 05 0 MILES 10CO 0 1CC0 21X0 3CC0 ■Ш) 5CC0 6000 7000 aco so» m NORTH CAROLINA QUADRANGLE LOCATION Interstate Route US Route Ramp State Route Local Road 4WD Interstate Route G US Route О State Route UTM GRID AND 201 1 MAGNETIC NORTH DECLINATION AT CENTER OF SHEET U.S. National Grid 100,000-m Square ID LV Grid Zone Des ignation 17S FEET CONTOUR INTERVAL 40 FEET NORTH AMERICAN VERTICAL DATUM OF 1988 This map was produced to conform with version 0.5.10 of the draft USGS Standards for 7.5-Minute Quadrangle Maps. A metadata file associated with this product is draft version 0.5.1 2 Research supported by the U.S. Geological Survey, National Cooperative Geologic Mapping Program, under USGS award number G11AC20296. 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 express or implied, of the U.S. Government. Mars Hill Barna rdsville Mount Mitchell Weaverville Craggy Pinnacle Montreat Asheville Oteen Black Mountain CRAGGY PINNACLE, NC 201 1 ADJOINING 7.5' QUADRANGLES 'Whole Rock Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP) analysis conducted by Acme Analytical Laboratories, LTD., 852 E. Hastings St., Vancouver, BC 2Sample numbers correspond to thin section and whole rock sample localities shown on geologic map 3PPM = parts per million 4LOI = loss on ignition in percent 5SUM = Sum total in percent -Q О c x: CD 05 STRUCTURAL FEATURES CONTACTS Solid line - located in field to within 150 meters Short-dashed - location inferred; querried where uncertain Stratigraphic Contact STRIKE AND DIP OF PLANAR FEATURES Ot о 52 Foliation X Vertical Joint BEARING AND PLUNGE OF LINEAR FEATURES \5 2g Mylonitic Foliation ^ Vertical Mylonitic Foliation ^ Vertical Foliation 78 Axial Plane 4 As Joint Small Fold Axis Slickenlines *34 Minor Fault l Mineral Lineation 1 ^ Crenulation /43 Cross Cutting Trend NON-STRUCTURAL FEATURES O Float Location MINERAL RESOURCES ВС391Д Thin section sample site. ^ Mine or quarry X Prospect COMMODITY LETTER SYMBOLS: Vrm Vermiculite s/g Sand and gravel TECTONIC AND METAMORPHIC CONDITIONS 9 locations where kyanite was observed in hand sample О locations where sillimanite was observed in hand sample X X X antiform synform overturned overturned antiform synform TRAVERSE MAP Red lines show paths of field traverses. Unit Contact ■ Form Lines О This Open-File Map is preliminary. 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. Bedrock Geologic Map of the Craggy Pinnacle 7.5-minute Quadrangle, North Carolina By Bart L. Cattanach, Richard M. Wooten and G. Nicholas Bozdog Geology mapped from August 201 1 to May 2012. Field assistance by Abigail Bullard. Map preparation, digital cartography and editing by G. Nicholas Bozdog, Bart L. Cattanach and Richard M. Wooten. 2012 90 -Z10Z de|/\| e||j uedQ ‘ainuiLu-g-/ eioeuuid A66ej