Appendix a the Stratigrapic Nomenclature of Burnsville Cove, Bath and Highland Counties, Virginia
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Appendix A The Stratigrapic Nomenclature of Burnsville Cove, Bath and Highland Counties, Virginia Christopher S. Swezey and John T. Haynes The Paleozoic rocks of the Appalachian region have Chatfieldian-Turinian Stages, and Taylor et al. (2013) been the target of geologists’ attention since the indicate that these two stages are within the Upper earliest days of geology in the United States. Not Ordovician Series. The Ordovician-Silurian boundary surprisingly, two centuries of attention have resulted in is customarily placed at the contact between the Ju- a long and complicated discourse concerning niata Formation and the overlying Tuscarora Forma- descriptions of rock units, what names to give to them, tion (Diecchio 1985), although in some publications and how to define the boundaries between them. this boundary is placed at a prominent unconformity Chapter 16 presents geologic maps, sections, and within the Tuscarora Formation (Dorsch et al. 1994; descriptions of the rocks in Burnsville Cove. The Dorsch and Driese 1995). objective of this appendix is to provide additional The Silurian Period is divided into the following information following the rules of stratigraphic four series (from oldest to youngest): Llandovery, nomenclature as described in North American Com- Wenlock, Ludlow, and Pridoli. The older two series mission on Stratigraphic Nomenclature (1983) and in are designated informally as lower Silurian, whereas Salvador (1994). Specifically, this appendix describes the younger two series are designated informally as the history of stratigraphic nomenclature use in Bath upper Silurian (Gradstein et al. 2004). Le Van and and Highland Counties, the type sections of the Rader (1983) and Diecchio and Dennison (1996) stratigraphic units, and the contacts between units. placed the lower Silurian-upper Silurian boundary at For easy reference, the lithostratigraphic and the contact between the Rose Hill Formation and the chronostratigraphic columns from Chap. 16 are overlying Keefer Formation, whereas Harris et al. duplicated (Fig. A.1). In this figure, the Middle (1994) placed the boundary at the contact between the Ordovician-Upper Ordovician boundary is placed at Clinton Group (e.g., Keefer Formation) and the over- the base of the Nealmont Formation, although this lying McKenzie Formation. The Silurian-Devonian location is somewhat controversial. Le Van and Rader boundary is located within the upper part of the (1983) placed the Middle Ordovician-Upper Ordovi- Keyser Limestone of the Helderberg Group (Denkler cian boundary at the contact between the Lincolnshire and Harris 1988a, b; Harris et al. 1994; Rodríguez Limestone and the overlying Ward Cove Limestone 2005), and the Lower Devonian-Middle Devonian (both of these limestone units are located well below boundary is located within the Needmore Shale the Nealmont Limestone of this paper), whereas (Rossbach and Dennison 1994; Harris et al. 1994). Harris et al. (1994) and Ryder et al. (1996) placed the Using uranium-lead dating techniques, Roden et al. Middle Ordovician-Upper Ordovician boundary (1990) obtained an absolute age of 390 ± 0.5 Ma from within the basal part of the Reedsville Shale. A more the Tioga Ash Bed. Finally, the Middle Devonian- recent publication by Young et al. (2005), however, Upper Devonian boundary is placed at the top of the reported conodont and isotope data that assign the Millboro Shale, but the uppermost few feet of the Dolly Ridge Formation to the Chatfieldian Stage Millboro Shale may be Upper Devonian (Rossbach and the underlying Nealmont Formation to the and Dennison 1994; Harris et al. 1994). W.B. White (ed.), The Caves of Burnsville Cove, Virginia, 459 Cave and Karst Systems of the World, DOI 10.1007/978-3-319-14391-0, © Springer International Publishing Switzerland 2015 460 Appendix A: The Stratigrapic Nomenclature of Burnsville Cove, Bath and Highland Counties, Virginia LITHOSTRATIGRAPHY CHRONOSTRATIGRAPHY Hampshire Formation AGE PERIOD STRATIGRAPHY (Ma) and LITHOLOGY 359.2 Hampshire Formation Foreknobs Formation Upper Foreknobs Formation (1,280 to 2,230’) 2000 Devonian Brallier Formation 385.3 Millboro Shale 1000 Middle Devonian Tioga Ash Bed Brallier Formation 397.5 Needmore Shale (1,550 to 3,000’) Oriskany Sandstone Lower 0 feet Devonian Helderberg Group 416.0 upper Tonoloway Limestone Silurian MF, WS, WCF 422.9 Millboro Shale Keefer Formation lower (230 to 1,370’) Rose Hill Formation Silurian Tuscarora Formation Needmore Sh. (20 to 150’) 433.7 Oriskany Ss. (20 to 130’) Helderberg Group Juniata Formation Tonoloway Ls. (300 to 400’) Upper (420 to 500’) Wills Creek Fm. (0 to 50’) Ordovician Oswego Sandstone Williamsport Ss. (20 to 35’) McKenzie Fm. (15 to 250’) Rose Hill Fm. Keefer Formation (5 to 50’) Reedsville Shale (300 to 800’) 460.9 Tuscarora Fm. (40 to 120’) Middle Dolly Ridge Formation Juniata Formation Nealmont Limestone Ordovician pre-Nealmont limestone (340 to 740’) 471.8 Oswego Ss. (25 to 85’) Lower Ordovician Reedsville Shale (1,000 to 1,400’) = sandstone = sandstone & siliciclastic mudstone Dolly Ridge Formation = siliciclastic mudstone (ca. 450’) Nealmont Ls. (ca. 150’) = limestone pre-Nealmont limestone Fig. A.1 Lithostratigraphic and chronostratigraphic charts for Fm. Formation; Ls. Limestone; Ss. Sandstone; MF McKenzie strata in the vicinity of Burnsville Cove, Bath and Highland Formation; WCF Wills Creek Formation; WS Williamsport Counties, Virginia. Time scale is from Gradstein et al. (2004). Sandstone Appendix A: The Stratigrapic Nomenclature of Burnsville Cove, Bath and Highland Counties, Virginia 461 Ordovician Nealmont Limestone suggested that these strata in Virginia may be younger than the strata of Lowville age, and that they might be In the vicinity of Burnsville Cove, the Nealmont mapped as the Eggleston Limestone or the Cham- Limestone is a 150 ft thick unit of gray limestone. In bersburg Limestone. Woodward (1951) later mapped Bath and Highland Counties, these strata were mapped these strata in Highland County as the Salona For- by Darton (1899) as part of the Shenandoah Lime- mation, which he stated is the northeastern extension stone. Butts (1933) later mapped these strata in Bath of the Eggleston facies of the Trenton Limestone in and Highland Counties as part of the Lowville Lime- southwestern Virginia, and is comparable with the stone of the Black River Group, whereas Butts (1940) Oranda Formation and the basal Martinsburg Shale in mapped them as the “Lowville-Moccasin Limestone” the Shenandoah Valley. Kay (1956) mapped these of the Black River Group. Furthermore, Butts (1940) strata in Highland County and northern Bath County stated that in Highland County and Bath County these as the Onego (“Oranda”) Formation (or Onego strata are a true limestone named the Lowville Lime- Member of the Salona Formation), and he indicated stone, but further south these strata grade into a red that these strata grade into a bed of quartz sandstone argillaceous limestone named the Moccasin Forma- overlain by limestone (mapped collectively as the tion. Woodward (1951) mapped these strata in High- Eggleston Formation) in southern Bath County. Bick land County as the Nealmont Formation, and he stated (1962) later mapped these strata in Bath and Highland that the strata can be traced south into the Eggleston- Counties as the Edinburg Formation. Perry (1972) Moccasin Formation. Kay (1956) mapped these strata noted that the equivalent strata in Pendleton County as the Nealmont Formation in Highland County, (West Virginia) do not resemble the Onego Member, although he used the names “Moccasin-Nealmont Salona Formation, or Edinburg Formation at their Formation” and “Nealmont-Moccasin Formation” in respective type sections, and therefore he proposed the Bath County. At an outcrop near Bolar (near western name Dolly Ridge Formation for these strata in edge of Burnsville Cove geologic map; Fig. 16.3), he Pendleton County. Subsequent publications have fol- described these strata as limestone with a few red lowed Perry (1972) and used the name Dolly Ridge argillaceous beds in the upper part of the unit. Bick Formation for these strata in Bath and Highland (1962) later mapped these strata in Bath and Highland Counties (Le Van and Rader 1983; Diecchio 1991; Counties as the Moccasin Formation, but subsequent Rader and Wilkes 2001). At present, these strata in the publications have used the name Nealmont Limestone vicinity of Burnsville Cove are mapped as the Dolly or Nealmont Formation (Read 1980; Le Van and Ridge Formation. The type section of the Dolly Ridge Rader 1983; Diecchio 1991). At present, these strata in Formation is on the southeastern side of Dolly Ridge, the vicinity of Burnsville Cove are mapped as the 1.3 km south of Riverton in Pendleton County, West Nealmont Limestone. The Nealmont Limestone is Virginia (Perry 1972). named for the village of Nealmont in Blair County, Pennsylvania, but the type section is at Union Furnace Ordovician Reedsville Shale in Huntingdon County, Pennsylvania (Kay 1941, 1944a, b). In the vicinity of Burnsville Cove, the Reedsville Shale is a 1,000–1,400 ft thick unit of gray shale. In Ordovician Dolly Ridge Formation Bath and Highland Counties, these strata were mapped by Darton (1899) as part of the Martinsburg Shale. In the vicinity of Burnsville Cove, the Dolly Ridge Butts (1933, 1940), Woodward (1951), Kay (1956), Formation is a 450 ft thick unit of black to gray and Bick (1962) mapped these strata in Bath and limestone. In Bath and Highland Counties, these strata Highland Counties