VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICATION 57 POST-MARTINSBURG ORDOVICIAN STRATIGRAPHY OF VIRGINIA AND WEST VIRGINIA Richard J. Diecchio COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOURCES R<>bert C. Milici, Commissioner of Mineral Resources and State Geologist CHARLOTTESVI LLE, VIRG IN IA 1 985 VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICATION 57 POST-MARTINSBURG ORDOVICIAN STRATIGRAPHY OF VIRGINIA AND WEST VIRGINIA Richard J. Diecchio COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOURCES Robert C. Milici, Commissioner of Mineral Resources and State Geologist CHARLOTTESVI LLE, VI RGI N IA 1 985 FRONT COVER: Two cycles within the Juniata Formation, Cumberland, Maryland. Jacob's staff is 5 feet long, graduated in feet. Bottom of staff marks base of lowermost sandstone bed (base of cycle). Basal sandstone is here channeled into the underlying mudstone. Top of Jacob's staff marks the middle Sholithos- bearing portion of cycle. Mudstone overlies the Skoli,thos facies and continues up to base of overlying sandstone bed, marking the base of the next cycle. VIRGINIA DIVISION OF MINERAL RESOURCES PUBLICATION 57 POST-MARTINSBURG ORDOVICIAN STRATIGRAPHY OF VIRGINIA AND WEST VIRGINIA Richard J. Diecchio COMMONWEALTH OF VIRGINIA DEPARTMENT OF MINES, MINERALS AND ENERGY DIVISION OF MINERAL RESOURCES Robert C. Milici, Commissioner of Mineral Resources and State Geologist CHARLOTTESVI LLE, VI RGI N IA 1985 DEPARTMENT OF MINES, MINERALS AND ENERGY Richmond, Virginia O. GENE DISHNER, Director COMMONWEALTH OF VIRGINIA DEPARTMENT OF PURCHASE AND SUPPLY RICHMOND 1985 Publication available from Virginia Division of Mineral Resources, Box 366?, Charlottesville, VA 22g0g. Portions of this publication may be quoted if credit is given to the Virginia Division of Mineral Resources. It is recommended that reference to this report be made in the following form: Diecchio, R. J., 1985, Post-Martinsburg Ordovician stratigraphy of Virginia and West Virginia: Virginia Division of Mineral Resources Publication 57,77 p. CONTENTS Page Abstract 1 Introduction ............... .... .. 1 3 Acknowledgments 3 Location and geologic setting 3 Methods 3 Background and previous work 6 Stratigraphic framework ........... 6 Martinsburg Formation and equivalent strata 6 Oswego Sandstone .......... 9 11 Juniata Formation . 16 Regional depositional patterns 2l Deposition of Upper Martinsburg strata 2l Deposition of Oswego and Juniata strata 27 Lateral relationships ..................... 30 Ordovician-Silurian boundary 30 Sea level history 31 References 32 Appendix I: Measured sections ......... 39 Appendix II: Well log data 69 Index 77 ILLUSTRATIONS Figure 1. Ordovician-Silurian correlation chart 2 2. Location map 4 3. Tectonic map 5 4, Palinspastic location map 7 5. Upper Ordovician-Lower Silurian correlation chart ................ 8 6. Isopach map of Martinsburg Formation and equivalent strata 10 7. Photomicrograph of Oswego Sandstone 11 8. Photomicrographs of lithic clasts in Oswego Sandstone t2 13 9. Photograph of Eurypterid impression in Oswego Sandstone . 10. Isopach map of Oswego Sandstone, palinspastic base 14 11. Trace fossils in Juniata Formation 15 t2. Outcrop photograph of cyclieal deposition within Juniata Formation 16 13. Diagrammatic generalized cycle within Juniata Formation 16 14. Depth zonation chart of trace fossils 16 15. Isopach and lithofacies map of Juniata Formation, palinspastic base t7 16. Paleocurrent histograms of Oswego and Juniata formations 18 t7. Summary map of paleoeurrent data 19 18. Photomicrograph of Tuscarora Sandstone 19 19. Isopach map of Tuscarora Sandstone 2A 20. Stratigraphic cross section A-A' 22 2r. Stratigraphic cross section B-B' 23 22. Stratigraphic cross section C-C' 24 23. Stratigraphic cross section D-D' 25 24. Stratigraphic cross section E-E' 26 25. Biostratigraphy at top of Martinsburg Formation 27 26. Maysville age paleogeography 27 27. Richmond age paleogeography 29 POST-MARTINSBURG ORDOVICIAN STRATIGRAPHY OF VIRGINIA AND WEST VIRGINIA Richard J. Diecchiot ABSTRACT The Ordovician/Silurian boundary exposed in the Valley and Ridge is disconformable in the eastern The Ashgillian (uppermost Ordovician) clastic synclinoria, conformable in the central Valley and strata of the Central Appalachian basin were stu- Ridge, and paraconformable in the western anti- died in order to interpret their paleoenvironmental clines. history and sedimentary tectonics. Forty-three out- crop and thirteen subsurface data localities were investigated in the Valley and Ridge and Appala- INTRODUCTION chian Plateau provinces of central and northern Virginia, eastern West Virginia, and western Ma- The Ordovician and Silurian strata of the Central ryland. Appalachian basin may be subdivided into three The upper portion of the Martinsburg and Reeds- gross lithologic units. The lowermost unit is the ville formations is eharacterized by sandstones to upper portion of the Cambro-Ordovician carbonate mudstones containing shallow water fauna of the sequence, which terminates within the Upper Or- Orthorlrynchula br aehiopod biozone. This interval dovician, and is represented, throughout much of marks a eustatic lowering of sea level at the be- the Valley and Ridge, by the top of the Trentonian ginning of the Ashgill epoch. Stage. The top ofthis carbonate sequence generally The Oswego Sandstone and the Juniata Forma- is younger in the basin center (uppermost Edenian), tion, each of which overlies the Martinsburg, are and older toward the eastern basin margin (top facies-equivalent to each other. West of 80o W of the Black River stage), consistent with the west- longitude the Oswego is.absent, and the Juniata ward progradation and associated overstep by the conformably overlies the Martinsburg and Reeds- overlying clastic wedge. The middle unit is com- ville formations, except in the Salem (Catawba) prised of the Cincinnatian (Upper Ordovician) syncline where the Juniata is for the most part also through Niagaran (Lower Silurian) strata, a west- disconformably absent. To the east, and throughout ward-transported clastic sequence that was derived most of the Valley and Ridge, the Oswego confor- from an eastern source. Cayugan (Upper Silurian) mably lies above the Martinsburg and Reedsville strata make up the basal portion of the upper unit, and below the Juniata. In easternmost outcrop a carbonate sequence thaf terminates at the top belts, the Juniata lithology is absent, having of the Lower Devonian Helderbergian Stage. changed facies into the Oswego. The Oswego con- Figure 1 is a correlation diagram of the Ordovician formably overlies the Martinsburg, except in the and Silurian units of the Central Appalachians. Massanutten synclinorium where it is disconfor- and Silurian units of the Central Appalachians. mably absent. The earliest appearance of the Ordovician-Si- The Oswego Sandstone, green to gray litharenite lurian clastic sequence exposed in northern and to lithic wacke, was derived from an eastern (oro- central Virginia and adjacent West Virginia is the genic) source area. The Oswego was probably de- Martinsburg Formation. These strata are equiva- posited in shallow marine conditions. The Juniata lent to late Champlainian Trenton age limestone Formation is a cyclically bedded sequence of red in southern Virginia (Twenhofel and others, 1954). to green sandstone, mudstone, and shale derived Farther southwest in Virginia and Tennessee, e- from a source area in Pennsylvania. The Juniata quivalent intervals are occupied by the Bays-Moc- Formation is nonmarine to shallow marine, and casin redbeds, which comprise the Blount delta, was deposited during a low stand of sea level. The an early phase (Blount phase of Rodgers, 1971, p. widespread transition from the Juniata Formation 1165) of sedimentation associated with the Taconic to the Tuscarora Sandstone probably represents a Orogeny. The Martinsburg is a coarsening-upward eustatic rise in sea level at the end of the Ordovician. clastic unit whose upper, sandy intervals pass lDepartment of Geology, George Mason University, Fairfax, VA 22030 VIRGINIA DIVISION OF MINERAL RESOURCES q u g o z E SOUTHWEST VA. BASIN CENTER ALLEGHENY FRONT GREAT U ff$ -8 -a Fz bz (LEE CO., VA.) (CENTRAL W. VA.) (HTGHLAND-CBATG CO., VA.) VALLEY :< x< (ROCKTNGHAM-BOTETOURT CO., VA.) ^E zi )"' z=E U U U = 1-" Salina Tonoloway Ls. Tonoloway Ls. Group Wills Creek Wills Creek Fm. Wills Creek Fm. ! Hancock Dol Williamspof Williamsport Fm ' Bloomsburg J Fm. McKenzae z Dol Fm. - G "Keefer" l Ss. Bochester Sh Mitflintown 6 Fm. z.g ; Keefer Ss. -=Keetef Ss. .E 6 Rose Hill Fm Rose Hillfm. Rose Hill Fm. Rose Hill Fm. - Massanutten 55. ! J Clinch Ss. Tuscarora Ss Tuscarora Ss Tuscarora Ss. Sequatchie Fm. Juniata Fm. Ju,niataH Fm. H\ g .; Reedsville Fm. Reedsville Sh. Reedsville sh. Fm. .g Martinsburg "Trenlon" ls. Dolly Ridge Trenton Ls. .g Fm. Eggleston E Nealmgnt z Eggleston Fm. Fm. g F Fm. t o Edinburg limestone of -Btack Htver oI E limestone (Liberty Hall) Black River age ts. River age Black Fm. _g limestone of Lincolnshire Ls. Dot Ls Wells Creek Chazy age -qJ Blackford Fm. New Market Ls .q E o j 'iiYii:iii::::::::::::ii:EiiitLz- .s' Rockdale E Run Fm. upper Knox Beekmantown Beekmantown Group Group o Stonehenge Ls F Figure 1. Ordovician-Silurian correlation chart, modified from Swartz and others (1942), Twenhofel and others (1954), Dennison (1982) and Rader (1982). PUBLICATION 57 westward into interbedded marine shales, silt- Transmission Corporation,