Triassic- Jurassic Stratigraphy Of
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Triassic- Jurassic Stratigraphy of the <JF C7 JL / Culpfeper and B arbour sville Basins, VirginiaC7 and Maryland/ ll.S. PAPER Triassic-Jurassic Stratigraphy of the Culpeper and Barboursville Basins, Virginia and Maryland By K.Y. LEE and AJ. FROELICH U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1472 A clarification of the Triassic--Jurassic stratigraphic sequences, sedimentation, and depositional environments UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1989 DEPARTMENT OF THE INTERIOR MANUEL LUJAN, Jr., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Library of Congress Cataloging in Publication Data Lee, K.Y. Triassic-Jurassic stratigraphy of the Culpeper and Barboursville basins, Virginia and Maryland. (U.S. Geological Survey professional paper ; 1472) Bibliography: p. Supt. of Docs. no. : I 19.16:1472 1. Geology, Stratigraphic Triassic. 2. Geology, Stratigraphic Jurassic. 3. Geology Culpeper Basin (Va. and Md.) 4. Geology Virginia Barboursville Basin. I. Froelich, A.J. (Albert Joseph), 1929- II. Title. III. Series. QE676.L44 1989 551.7'62'09755 87-600318 For sale by the Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 CONTENTS Page Page Abstract.......................................................................................................... 1 Stratigraphy Continued Introduction... ........................................................................................... 2 Newark Supergroup Continued Regional setting.. ................................................................................ 2 Culpeper Group Continued Previous investigations.......................................................................... 3 Mount Zion Church Basalt .................................................. 23 Scope, purpose, and method of study ................................................ 9 Midland Formation .................................................................... 24 Acknowledgments .................................................................................. 9 Hickory Grove Basalt ................................................................ 25 Stratigraphy................................................................................................ 10 Turkey Run Formation.............................................................. 26 Newark Supergroup ............................................................................ 10 Sander Basalt .......................................................................... 27 Culpeper Group ................................................................................ 10 Waterfall Formation .................................................................. 28 Manassas Sandstone.................................................................... 12 Millbrook Quarry Member .................................................. 29 Reston Member ...................................................................... 12 General discussion of the depositional model ........................ 30 Rapidan Member.................................................................... 13 Diabase............................................................. ................. ........ .. 31 Tuscarora Creek Member .................................................... 14 Distribution and mode of occurrence .............................................. 31 Poolesville Member................................................................ 15 Description of rock................................................................................ 31 Balls Bluff Siltstone.................................................................... 16 Geochemistry.......................................................................................... 32 Leesburg Member.................................................................. 19 Thermally metamorphosed rocks .......................................................... 32 Tibbstown Formation ................................................................ 20 Summary ............................. ....... ......... ..... .......... .. 34 Mountain Run Member ........................................................ 20 References cited .......................................................................................... 35 Haudricks Mountain Member ............................................ 21 Appendixes: Catharpin Creek Formation .................................................... 22 A: Measured sections ............................................................................ 38 Goose Creek Member ............................................................ 22 B: Drill and core hole descriptions and columns .......................... 44 ILLUSTRATIONS PLATE 1. Triassic-Jurassic stratigraphy of the Culpeper and Barboursville basins, Virginia and Maryland. ......................... .....In pocket A. Evolution of stratigraphic nomenclature in the Culpeper and Barboursville basins, 1928 to present B. Generalized correlation diagram of the Newark Supergroup in the Culpeper, Newark, and Hartford basins C. Bedrock map of the Culpeper and Barboursville basins D. Simplified stratigraphic correlation diagram summarizing age and lithology of the Culpeper Group in the Culpeper and Barboursville basins Page FIGURE 1. Map showing principal Triassic-Jurassic basins containing the Newark Supergroup strata exposed in Eastern North America...................................--.--..-.................--.........---.........--......-.........-.--......--........-.-.-.-------.--.-..----...--..-. 3 2. Sketch map of the age of strata, Culpeper Group, Culpeper basin, Virginia and Maryland, showing the location of diagnostic palynologic samples and palynofloral zones and paleontologic localities........................................... .............. 5 3. Sketch map of the Culpeper basin, Virginia and Maryland, showing the location of measured sections and selected drill holes -----.---------..................---------.--.........----........---......---.---..--......---.......--....---....--....---..----.-.----. 6 4-7. Photographs showing: 4. Outcrop of the Reston Member of the Manassas Sandstone in the northwestern part of the Independent Hill 7.5-min Quadrangle, town of Manassas........................ ................................... ...................... ... ... 13 5. Outcrop of the Poolesville Member of the Manassas Sandstone in the western part of the Independent Hill 7.5-min Quadrangle .................................................................................................... ..... ....... .. .. 15 6. Upper surface of the Poolesville Member of the Manassas Sandstone showing carbonate nodules and cement ---..-....................-.---.--..-...............---..........---.......--..........-...-....--.........--......--.....--..----.....---.-..--..-- 15 7. Outcrop of the Poolesville Member of the Manassas Sandstone exposed on the west bank of the Potomac River near the end of Virginia State Route 656, Loudoun County, Va............. ...... ..... .. ........ 16 ill IV CONTENTS Page FIGURES 8-14. Photographs showing: 8. Bedding plane exposure of ripple marks and mud cracks in the Balls Bluff Siltstone on a quarried slab at the Culpeper Crushed Stone quarry, Stevensburg, Culpeper County, Va. .......................................................... 17 9. Balls Bluff Siltstone exposed in north quarry face at the Culpeper Crushed Stone quarry near Stevensburg, Culpeper East 7.5-min Quadrangle ............................................................................................ 17 10. Bedding plane exposure of dinosaur tracks in mud-cracked Balls Bluff Siltstone at the Culpeper Crushed Stone quarry, Stevensburg, Culpeper County, Va................................................................................................... 18 11. Exposure of a limestone conglomerate in the Leesburg Member of the Balls Bluff Siltstone in a road cut of U.S. Route 15, north of Leesburg, Va......................................................................................................................... 19 12. Outcrop of indurated greenstone conglomerate of the Mountain Run Member of the Tibbstown Formation exposed at the west end of Chandler Street, Culpeper, Va......................................................................... 21 13. Outcrop of interbedded sandstone and siltstone of the Catharpin Creek Formation in the east-central part of the Thoroughfare Gap 7.5-min Quadrangle................................................................................................ 22 14. Mount Zion Church Basalt exposed on the north cuts of the Southern Railroad about 50 m northwest of the intersection with U.S. Route 15, in the east-central part of the Thoroughfare Gap 7.5-min Quadrangle........................................................................................................................................................................... 23 15. Photomicrograph of the Mount Zion Church Basalt from an exposure in Virginia State Route 600 east of Bull Run ........................................................................................................................................................^ 24 16,17. Photographs showing: 16. Exposure of the Hickory Grove Basalt on the south bank of Broad Run