VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICATION 124 THE VALLEY COALFIELD (MISSISSIPPIAN AGE) IN MONTGOMERYAND PULASKI COLINTIES, VIRGINIA Mervin J. Bartholomew and K. Elizabeth Brown COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS, AND ENERGY DIVISION OF MINERAL RESOURCES Stanley S. Iohnson, State Geologist CHARLOTTESVILLE, VIRGINIA t992 VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICAfiON 124 THE VALLEY COALFIELD (MISSISSIPPIAN AGE) IN MONTGOMERYAND PULASKI COUNTIES, VIRGINIA Mervin J. Bartholomew and K. Elizabeth Brown COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS, AND ENERGY DIVISION OF MINERAL RESOURCES Stanley S. Johnson, State Geologist CHARLOTTES VILLE, VIRGINIA 1992 CONTENTS P*se - -o- Sructural Cloyd Conglomerate Member ..................;. ...........5 Lower member .............6 Upper member....... ........7 Interpretation Cloyd Conglomerat€ Member .........10 Lower member ............10 Upper member .................... ............11 ILLUSTRATIONS Plate l. Geologic map of Devonian and Mississippian stata in Montgomery and Pulaski Counties, Virginia.................in pocket 2. Stratigraphic correlation diagram of coal measures ..........in pocket Figure 1. Structural contour map drawn on top of coal measures ..............2 2. Typical Brallier 3. Closeup of a Chemung Formation fossil-hash bed overlying fine-grained sandstone ........4 4. Typical Chemung Formation 5. Ledge of Cloyd Conglomerate Mernber overlying Chemung sandstone .........6 6. Remnants of the Cloyd 7. 'Red bed" of the Cloyd Conglomerate Member .........................6 8. Typical lithology of the lower member of the Price Formarion ......................7 9. "Sandstone markerbed" and coal 10. The Langhorne coal showing well-developed southeast-dipping cleavage .........................8 11. The Merrimac interval showing bedding within coal ............ .........................8 12. Typical lithology of the upper member of the Price Formarion ......................9 14. Quartz-pebble conglomerate of the upper member of the Maccrady Formation ..................9 15. Stratigraphic column of the hice 16. Interpretive map showing some depositional features of the Price Formation .............. ........................13 TABLE l. Point-count analyses of marine, non-marine and "marker bed" sandstone................ .........1I DEPARTMENT OF MNES, MINERALS, AND ENERGY RICHMOND, VIRGINIA O.Gene Dishner, Director DIVISION OF MINERAL RESOIJRCES CHARLOTTESVILLE, VIRGINIA Stanley S. Johnson, State Geologist STAI]F Kay T.Ramsey, Executive Secretary RESEARCHBRANCII James F. Conley, Manager INFORMATION SERVICES AND APPLIED GEOLOGY SECTION PI]BLICATIONS SECTION Thomas M. Gathright,II, Section Head Eugene K. Rader, Section Head and E<litor Elizabeth V. M. Campbell, Geologist Senior D. Allen Penick, Jr., Geologist Senior Karen K. Hostettler, Geologist Senior Vemon N. Morris, Cartographic Drafter Assistant David A. Hubbard, Jr., Geologist Senior Roy S. Sites, Geologist Senior ECONOMIC GEOLOGY SECTION Gerald P. Wilkes, Geologist Senior Palmer C. Sweet, Section Head William F. Giannini, Geologist Senior SOUTIIWEST SECTION Jack E. Nolde, Geologist Senior Alfred R. Taylor, Section Head Michael L. Upchurch, Geologist Senior William S. Henika, Geologist Senior James A. Lovett, Geologist Senior GEOLOGIC MAPPING SECTION William W. Whitlock, Geologist Senior C. R. Berquist, Jr., Geologist Senior Nick H. Evans, Geologist Senior John D. lvlarr, Jr., Geologist Senior SUPPORTBRANCH Delores J.Green, Office Manager Lou A. Carter, Office Services Specialist Christopher B. Devan, Librarian Daniel W. Johnson, Housekeeping Worker Charles B. Marshall, Geologist Technician Edwin W. Marshall, Geologist Technician Paige S. Roach, Store Operations Supervisor Copyright 1992 Commonwealth of Virginia Thispublicationisbasedon thebestinformationavailableto thecompilersatthetimeofitscreation. TheVirginiaDivision of Mineral Resources cannot guarantee this publication to be free from errors or inaccuracies, and disclaims responsibility or liability for interpretations or decisions based thereon. Portions of publications may be quoted if credit is given to the authors and the Division of Mineral Resources. CONTENTS P*oe Cloyd Conglomerate Member ..................i. ...........5 Lower member .............6 Upper member....... ........7 Interpretation Cloyd Conglomerate Member Lower member ............10 Upper member ............1I ILLUSTRATIONS Plate l. Geologic map of Devonian and Mississippian strata in Montgomery and Pulaski Counties, Virginia.................in pocket 2. Stratigraphic correlation diagram of coal measures ..........in pocket Figure 1. Structural con0our map drawn on top of coal measures ..............2 2. Typical Brallier 3. Closeup of a Chemung Formation fossil-hash bed overlying fine-grained sandstone ........4 4. Typical Chemung Formation 5. Ledge of Cloyd Conglomerate Member overlying Chemung sandsrone .........6 6. Remnants of the Cloyd *Red 7. bed" of the Cloyd Conglomerate Member .........................6 8. Typical lithology of the lower member of the Price Formation ......................7 9. "Sands0one markerbed" and coal 10. The Langhome coal showing well-developed southeast-dipping cleavage .........................8 11. The Merrimac interval showing bedding within coal ............ .........................8 12. Typical lithology of the upper member of the Price Formarion ......................9 14. Quartz-pebble conglomerate of the upper member of the Maccrady Formation. .................9 15. Stratigraphic column of the Price F 16.InterpretivemapshowingsomedepositionalfeaturesofthePriceFormation TABLE 1. Point-count analyses of marine, non-marine and "marker bed" sandstone.................. .......1I THE VALLEY COALFIELD MISSISSIPPIAN AGE) IN MONTGOMERY AND PULASKI COUNTIES, VIRGINIA Mervin J. Bartholomewl and K. Elizabeth Brown2 ABSTRACT because ofthe potential ofthe coal-bearing strata to serve as a source rock for natural gas beneath the Pulaski thrust sheet. Coal-bearing srata of Mississippian age lie structurally Within a large portion of these two counties the thrust sheet below the Pulaski thrust sheet in Montgomery and Pulaski is gently folded and the coal beneath lies atrelatively shallow counties, Virginia. These coal-bearing strataare found in the depths. This combination ofbroad, open folds beneath a lowerportion of the upper(nonmarine) memberof thePrice thrust surface at shallow depths provides potential for anti- Formation. The lower coal measures, which lie directly clinal orfault-bounded gas traps as well as easy migration of above the lower (marine) member of the Price, are interpreted gas into the anticlinal and fault-bounded structures. as probable lower delta-plain coals, whereas those in the Field work on the coal-bearing strata was begun by M.J. upper portion of the coal measrres appear more like upper Bartholomew during the spring of 1978 in the Blacksburg delta-plain coals. WithinPulaski andMontgomery Counties quadrangle (Bartholomew and Lowry,1979). Between the the coal measures of the upper Price Formation underlie summers of 1979 and,1980 mapping of the coal measures in approximately 150 square miles in an arearoughly bounded the Radford North and Staffordsville quadrangles was com- by Brush, Cloyd and Little Walker Mountains on the north- pletedby Bartholomew assisted by A.P. Schultz, K.E. Brown west; Tract and Draper Mountains on the west; Draper, Ingles andG.R. Ingram. During thesummerandfallof 1980Brown, and Barringer Mountains on the southeast; and a north- Ingram and Bartholomew mapped the coal measures in the trending line from Christiansburg to Brush Mountain on the Long Spur, Whit€ Gate, Pulaski, Newport, and McDonalds east. The coal measures are structurally runcated to the Mill quadrangles. Samples collected during 1980 for geo- southeast and east" respectively, by ttre southeast-dipping chemical evaluation and weathering studies (Ingram, 198 1; Pulaski fault ramp and the east-dipping Pulaski-Caawba Ingram and Rimstidt, 1984) and sections of the coal mea- faultlateralramp. Snucnualcontours generated from limited sures were described (Appendices I & ID for a study of the subsurface data (22 points) suggest the coal measures may environment of deposition of the coal (Brown, 1983). In occuratdepths as greatas -2500 feetin theRadford areaand 1981, five shallow (less than 50 feet) core holes were drilled northward along New River. By contrast the outcrop belts along the southeastern flanks of Brush, Cloyds, and Little ofcoal generally exceed +2000 feet in elevation indicating WalkerMountains (Appendix III). In the spring of 1981 the that structural relief exceeds 4000 feet. Fast of the Pulaski- Department of Geological Science, Virginia Polytechnic Catawba fault lateral ramp the coal measures formed the Institute and State University drilled a shallow core hole footwall glide horizon along which the thrust moved; thus, along the northwestern flank of Price Mountain (Appendix only thin, scatt€red, teclonic wedges of coal are likely !o be III, #6). The Department of Geological Science (funded by found in northeaslern Montgomery County. Virginia Division of Mineral Resources and the U.S. Geo- A line extending from the mouth of Poverty Creek logical Survey) ran two vibroseis lines (Dysart, 1983) across southward to the western end of the Price Mountain window a portion of the Radford North and Blacksburg 7.5-minute appsrs !o mark the locus of importantchanges in sedimen- quadrangles for the Division during the