GENERALIZED STRATIGRAPHY OF SOUTHEASTERN WEST VIRGINIA
Mississippian
Mauch Chunk Group 1770-3450 feet
Greenbrier Limestone 750-1800
Maccrady Formation 25-350
Price Formation 500-1000
Devonian
Hampshire Formation 0-840 feet
Chemung Formation 500-3000
Brallier Formation 400-2500
Millboro Shale 150-1000
Huntersville Chert 30-75
(the glauconitic Bob's Ridge Ss occurs
locally at the top of the Huntersville)
Oriskany Sandstone 25-75
Helderberg Group 200-400
Licking Creek Limestone 51-90
Healing Springs Sandstone 0-90
New Creek Limestone 0-18
Silurian
Keyser Limestone (Sil-Dev) 60-250
Clifton Forge Sandstone 0-150
(a tongue within the Keyser)
Cayugan Series
Tonoloway Limestone 100-330
Wills Creek Formation 0-220
Williamsport Sandstone 0-50
Niagaran Series
McKenzie Formation 0-140
Rochester Shale 0-20
Keefer Sandstone 7-35
Rose Hill Formation 210-500
(the Rose Hill, Keefer, and
Rochester together = Clinton)
Tuscarora Sandstone 70-190
Ordovician
Juniata Formation 150-600
Martinsburg Formation 1000-2400
Black River Limestone 210
Lincolnshire Limestone 45-200
New Market Limestone 0-200
Knox Group 600-2000
BRIEF DESCRIPTIONS OF STRATIGRAPHIC UNITS IN SE WEST VIRGINIA
MISSISSIPPIAN SYSTEM
MAUCH CHUNK GROUP: 1770-3450 feet. Mostly nonmarine shales and sandstones, usually red in color; occasional thin marine limestones with fossils.
GREENBRIER LIMESTONE: 750-1800 feet. Shallow water limestones ranging from carbonate mudstones to grainstones, usually gray in color; fossils may be common.
MACCRADY FORMATION: 25-350 feet. Entirely nonmarine shales and sandstones, typically bright red in color.
PRICE FORMATION: 500-1000 feet. Mostly marine sandstones, siltstones, and shales, usually brown to gray in color; fossils present, but not common; nonmarine conglomerate often present at base.
DEVONIAN SYSTEM
HAMPSHIRE FORMATION: 0-840 feet. Entirely nonmarine sandstones and shales, usually pink to bright red in color. Sandstones are typically cross bedded.
CHEMUNG FORMATION: 500-3000 feet. Marine sandstones, siltstones, and shales, typically brown to gray in color. There is a generally coarsening-upward sequence with shales dominant near the base and sandstones dominant near the top. Fossils are present, but not common; some sandstones near the top are abundantly fossiliferous.
BRALLIER FORMATION: 400-2500 feet. Marine siltstones and shales, thin bedded and typically dark brown to gray in color. The contact with the overlying Chemung is gradational and usually drawn where several beds of sandstone greater than two feet thick are present. The contact with the underlying Millboro is also gradational and is drawn where the laminated black shales of the Millboro give way to the thin-bedded shales and siltstones of the Brallier. Fossils are rare.
MILLBORO SHALE: 150-1000 feet. Black fissile (very fine laminations) shale that weathers gray and readily forms soil. Sometimes the color of weathered shale can be brown or red, depending on its iron content. Saprolitic shales can be nearly white. Rare beds of micritic limestone up to a few feet in thickness can be found in the field camp mapping areas. Fossils are very rare, consisting of pelagic organisms and brachiopods.
HUNTERSVILLE CHERT: 30-75 feet. Mostly a highly silicified black shale containing beds that are brecciated and recemented with amorphous silica. Glauconitic and phosphatic layers are sometimes common. Brightly weathering-colors are common; shales are often pink or lavender, the highly siliceous material may be blue or blue-black. Locally at the top of the Huntersville is the glauconitic Bob's Ridge Sandstone, which is approximately 3 feet thick. Fossils may be present, but they are not common.
ORISKANY SANDSTONE: 25-75 feet. Coarse-grained, thick to massively bedded calcite-cemented sandstone that is often blue-gray to dark gray or sometimes white, where fresh, and brown on weathered surfaces. Some exposures have silica cement rather than calcite cement. Fossils may be common, including molds of brachiopods and crinoid stems. The contact between the Oriskany and underlying Licking Creek Limestone is often gradational.
HELDERBERG GROUP: 200-400 feet. Shallow water limestones ranging from carbonate mudstone to grainstone, usually gray in color. The Licking Creek Limestone is fossiliferous and often cherty. The Healing Springs Sandstone, which is up to 90 feet thick, has silica cement, contains abundant crinoid stem molds, and weathers a very distinct light brown. The New Creek Limestone, which is very thick to the north, is very thin and is typically micritic. The underlying Keyser Limestone is a fossiliferous, coarse-grained limestone. The Silurian-Devonian systemic boundary is within the Keyser.
SILURIAN SYSTEM
TONOLOWAY LIMESTONE: 100-330 feet. Interbedded laminated argillaceous limestone and minor calcareous shale, usually dark gray in color. The laminated beds weather out as slabs or plates. Fossils are uncommon, but occasional layers of ostracods and stromatolites can be found.
WILLS CREEK FORMATION: 0-220 feet. Mostly dark calcareous shales with some interbedded dark, argillaceous limestones. Some outcrops contain olive-green shales similar to the upper Rose Hill Fm. This formation weathers very easily and is not well exposed in the field camp mapping areas. In the Huntersville-Minnehaha Springs area there is a 5-10 foot sandstone within the Wills Creek Fm. that is lithologically similar to the Williamsport Sandstone. This sandstone is informally called the Rainbow Run Sandstone Member of the Wills Creek Formation.
WILLIAMSPORT SANDSTONE: 0-50 feet. A resistant quartz-rich sandstone which weathers light brown; fresh surfaces may be white. At some localities a zone of ostracods can be found at the base in interbedded shale and sandstone.
MCKENZIE FORMATION: 0-140 feet. Thin-bedded highly fossiliferous limestones with thin interbedded calcareous shale. This unit, along with the Williamsport, is fairly resistant and makes a good mapping unit.
ROCHESTER SHALE: 0-20 feet. Dark gray shales and thin sandstones. A variety of fossils have been reported from the Rochester farther north, but in the Field Camp area the shales are not particularly fossiliferous.
KEEFER SANDSTONE: 7-35 feet. Dense fine-grained gray-white or brown sandstone. Its most notable characteristic is that it can contain a lower and/or upper zone of hematite. These hematite layers may be up to 8 inches thick and are typically bright red. Sometimes the hematite is oolitic.
ROSE HILL FORMATION: 210-500. Marine sediments ranging from red sandstones and shales in the lower part to olive-green shales and siltstones in the upper part; the lower part is equal to the Cacapon Fm. in Virginia. The red beds are marine as ostracods and brachiopods can be found in them as well as the olive-green shales. The red color is typically darker (maroon) and not as bright red as in the Juniata Formation.
TUSCARORA SANDSTONE: 70-190 feet. Fine to coarse-grained, well-sorted, cross-bedded, quartz-rich sandstone which weathers white, pink, or gray. Quartz pebbles are often common, particularly at the base. Two zones of interbedded shales are present in the Tuscarora. Trace fossils are abundant, particularly large horizontal traces. Upper and lower contacts are gradational and are placed at the lowest and highest red beds, respectively. Generally interpreted as a nearshore and shoreline deposit. Very resistant; an important mapping unit.
ORDOVICIAN SYSTEM
JUNIATA FORMATION: 150-600 feet. Predominantly nonmarine redbeds (although there is evidence of marine trace fossils) composed of approximately equal amounts of shale and sandstone. The red color is very bright, like the Hampshire Formation, and unlike the darker reds of the Rose Hill Formation. A lagoonal facies with clams is present on Peters Mountain.
MARTINSBURG FORMATION: 1000-2400 feet. Marine sediments consisting of interbedded sandstones and shales near the top, ranging down to calcareous siltstones and shales near the base. The sandstones are mostly turbidites and are classic examples of graywacke. The contact with underlying limestone is gradational.
BLACK RIVER LIMESTONE: 210 feet. Essentially dark, micritic limestone with very few fossils. Represents relatively deep water deposition.
LINCOLNSHIRE LIMESTONE: 45-200 feet. Dark-gray, medium to coarse-grained, bioclastic, black-chert-bearing limestone with pink silty partings and medium-gray, coarse-grained, bioclastic, high-calcium limestone; fossiliferous.
NEW MARKET LIMESTONE: 0-200 feet. Light-gray to light-olive gray, thick-bedded, micritic, high-calcium limestone; locally argillaceous near the base.
KNOX GROUP: 600-2000 feet. Mostly gray or tan, thick-bedded or massive siliceous dolomite, locally brecciated. Units within this group also include light-gray, thin-bedded, fine-grained limestone, gray, pink, or light-brown chert in beds or nodules, and flat-pebble conglomerates. Quartz common in veins and vugs. Fossils other than stromatolites are rare, except in limestone beds.
TWK, revised 12-99