Mica Deposits of the Southeastern Piedmont Part 2. Amelia District, Virginia GEOLOGICAL SURVEY PROFESSIONAL PAPER 248-B Mica Deposits of the Southeastern Piedmont Part 2. Amelia District, Virginia By RICHARD W. LEMKE, RICHARD H. JAHNS, and WALLACE R.GRIFFITTS GEOLOGICAL SURVEY PROFESSIONAL PAPER 248-B Distribution and structure of pegmatite bodies in the area, their mineralogical characteristics, and the economic possibilities of the mica and other pegmatite minerals UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1952 UNITED STATES DEPARTMENT OF THE INTERIOR Oscar L. Chapman, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. - Price 60 cents (paper cover) CONTENTS Page Page Abstract _________________________________________ 103 Description of deposits—Continued Introduction: Field work and acknowledgments._______ 103 Jefferson-Amelia area—Continued Geography of the district____________________________ 104 Jefferson prospects______-_--._-----_------ - 118 Geology of the district-______________________________ 105 McCraw No. 3 (Old Pinchbeck No. 1) mine__. 119 Rock formations,___________________________ 105 McCraw No. 2 (Old Pinchbeck No. 3) mine__ 119 Metamorphic rocks_ ________________________ 105 McCraw No. 1 (Pinchbeck No. 2) mine__---_ 119 Igneous rocks______________________________ 105 Line mine__---___________________________ 120 Structure. _________________________________ 106 Booker mine______________--_-----___----. 120 Distribution and occurrence of the pegmatites __________ 106 0'Neil prospect-___________________________ 120 Structural features of the pegmatites._________________ 106 Patterson mine-_________----_-_----_-_ 120 Jefferson-Amelia area. _ _________________________ 106 Marshall mine_____________---_-----_-----. 120 Morefield-Denaro area.__________________________ 106 Winston mine__________-_--_-_------_ 120 Mineralogical features of the pegmatites.______________ 107 Berry mine.____________---_-------- 120 Simple pegmatites.____________________________ 107 Penn prospect.____________________________ 121 Pegmatites of complex mineralogy. _______________ 107 Trueheart prospect.._______________________ 121 Origin of the pegmatites.____________________________ 108 Rutherford mines._________________________ 121 Economic aspects of the pegmatite minerals. __________ 108 Abner Pinchbeck mine. _______--_-_--__ 125 Mica______----________________________________ 108 Wingo mine.____________----------_-- 126 Other minerals. _______________________ 108 Other deposits.________________---_-___--_. 127 Mining. _______________________________ 109 Morefield-Denaro area__________----_-__________ 127 History_--_____________________________________ 109 Morefield mine.-_________-----_----__-. 127 Mine workings and mini ng methods ______________ 109 H. T. Flippen prospect.____________________ 134 Production_____________________________________ 109 Dobbin prospect___________________________ 134 Future of the district____________________________ 109 Vaughan mine_-_--_______________________ 134 Descriptions of deposits.____________________________ 110 Vaughan prospect-_________________________ 134 Jefferson-Amelia area____________________________ 110 Milinda Harris Winfree prospects.___.______. 135 Pinchbeck No. 1 mine______________________ 110 Mottley mine _____________________________ 135 Pinchbeck No. 2 mine_______________________ 110 Golden prospect.__--__________-_-____-__-- 135 Pinchbeck No. 3 mine__- _______________ 110 D. E. Kraft prospect-______________________ 135 Pinchbeck prospects-.-__________________ 110 Wyatt Vaughan prospect- __________________ 135 McCraw No. 4 mine________________________ 110 Ponton mine______________________________ 136 Abner mine_______________________________ 110 Harrison Venable prospect-_ ________________ 136 Pine Shaft mine___ __________________ 111 Mays mine_-___-__________________________ 136 Nettie Taylor mine. _______________________ 111 Other prospects.-._____ ____________________ 136 Maria (Old Pinchbeck, Smith) mine.---_______ 111 Outlying deposits._________________________ 136 Jefferson No. 7 (Derrick Pit) mine-___________ 113 Ligon mines_______________________________ 136 Jefferson No. 6 mine________________________ 113 Keystone mine_____'_____-_-__----_____-_-- 137 Jefferson No. 5 (Fields) mine_________________ 113 Schlegal (Norfleet) mine.__________________ 137 Champion (Jefferson No. 4, Bland) mine_______ 114 James Anderson prospect._.______-.______-_ 138 Jefferson No. 3 (Champion No. 2) mine_ ______ 117 Other prospects____________________________ 138 Jefferson No. 2 mine. ____________________ 117 References cited___________________________________ 138 Jefferson No. 1 mine_ ______________________ 118 Index ____________________________________________ 139 in IV CONTENTS ILLUSTRATIONS Page PLATE 2. Map of a part of the Jefferson-Amelia area, Amelia County, Va., showing mica deposits. ______________ In pocket 3. Geologic map and section of the Maria mine, Amelia County_______________________________________ In pocket 4. Geologic map and sections of the Champion mine, Amelia County-__--_---------------__----_-_--- - In pocket 5. Geologic map and sections of the Rutherford mines, Amelia County _________________________________ In pocket 6. Geologic map and sections of the Morefield mine, Amelia County.------------------------------------- In pocket FIGURE 52. Index map of the Amelia district, Virginia, showing mica deposits... __-______-_______------___-____---- 104 53. Geologic map and sections of the Nettie Taylor mine, Amelia County.-______________________________ ______ 112 54. Zonal relations in the main pit of the Maria mine, Amelia County____----------------------------------- 113 55. Muscovite crystals in vugs, Champion pegmatite, Amelia County___-_-----_-------_-------------------- 115 56. Corroded albite crystals, Champion pegmatite___________________-.__________-----___-_--__-_-__---- 116 57. Map, plan, and sections of the Jefferson No. 1 mine, Amelia County.------------------------------------ 118 58. Geologic map and section of the Wingo mine, Amelia County_______________-_--______-__________,-.__--- 126 TABLES Page 1. Production of mica, feldspar, and other minerals from the Morefield mine, Amelia County, Va__-__--________________ 127 2. Mineral composition of samples from open-cut and bulldozer trenches, Morefield deposit-- _______________________ 132 MICA DEPOSITS OF THE SOUTHEASTERN PIEDMONT PART 2. AMELIA DISTRICT, VIRGINIA By KICHARD W. LEMKE, EICHAKD H. JAHNS, and WALLACE E. GKIFFITTS ABSTRACT Jefferson-Amelia area have yielded at least two-thirds of the During 1943-45 eighty-three mica mines and prospects in the mica produced in the district. Amelia district of Virginia were examined by the authors as Beryl, columbite-tantalite, and feldspar have been obtained part of the United States C4eological Survey's program of evalu­ from the Amelia district, and phenakite and topaz may b? of ating possible sources of strategic minerals. commercial value. The Amelia district is, like the rest of the Piedmont, an area of low relief. Most of the district is underlain by mica and INTRODUCTION: FIELD WORK AND hornblende schists and gneisses, which are intruded by granite, ACKNOWLEDGMENTS gabbro, and diabase. A large body of granite extends southward Investigations of mica deposits in the Amelia district from Amelia into North Carolina, and smaller bodies occur in other parts of the district. The foliation of the metamorphic were begun by the Geological Survey during the period rocks strikes northeast and dips moderately to steeply north­ ID 12-15, when D. B. Sterrett examined about, 20 de­ west, but it is contorted or folded in places, especially near posits and prepared sketch maps of at least 7. The bodies of intrusive rock. All the rocks are deeply weathered. Rutherford and Morefield mines were visited by J. J. Most of the pegmatites in the district are in a northward- trending belt 4 miles wide and 10 miles long. The northern part Glass and others in 1932, and the mineralogy of these of the belt is termed the Jefferson-Amelia area; the southern pegmatites was studied in detail during subsequent part, the Morefield-Denaro area. The pegmatites in the Jeffer­ years. L. R. Page briefly examined several mines rnd son-Amelia area are relatively short lenses that strike east. prospects in 1912, chiefly to determine their potentiali­ Those in the Morefield-Denaro area are dikes, much longer than ties as sources of tantalum minerals. A program of those farther north, that strike northeast. The pegmatites of systematic and detailed investigations of mica deposits both areas may be related to the Redoak granite of Laney, and the magma from which the pegmatite bodies crystallized was was started by R. W. Lemke in 1943 and was continued emplaced along fractures that cross the country-rock foliation. intermittently until the fall of 1945 by Lemke, W. E. The pegmatites are well zoned, commonly having quartz cores, Griffitts, and R. H. Jahns. Capable field assistance perthite-rich intermediate zones, and plagioclase-rich wall zones. during the earlier stages of the work was provided by Like other zoned pegmatites in the Southeastern States, most of the bodies crystallized from the walls inward after the magma J. H. Stillwell, R. L. Smith, Edward Ellingwoocl III, was emplaced. and Rosewell Miller III. In all, 40 mines and 43 Mica is commercially the most important mineral; in the