|Geologic age||Middle Devonian|
Sedimentary > Clastic > Mudstone > Shale > Black-shaleblack gas shale
Sedimentary > Carbonate > Limestone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone
|Comments||part of Hamilton Group 1700-2800 ft. (520-850 m). Secondary unit descriptions from USGS Lexicon website (ref. NY046) and references NY015, NY024, and NY025: Marcellus Shale of the Hamilton Group is the oldest of the extensive black gas shales. Unit crops out in the Valley and Ridge from southeastern NY to northern WV. The Marcellus or its partial equivalent the Millboro Shale, is present in the subsurface in NY, PA, OH, western MD, VA, WV, and northeastern TN. Consists for the most part of sooty black shale and a few beds of medium-gray shale and limestone nodules or beds of dark gray to black limestone. Marcellus is approximately 1,000 ft thick in central PA, but thins to the north, west, and south. Feathers out in eastern OH, western WV, and southwestern VA. The Cherry Valley Limestone Member is an extensive unit in the subsurface of NY, PA, and WV (deWittand others, 1993). Marcellus Formation will be formally raised to subgroup status within the Hamilton Group and be divided into a lower Union Springs Formation and an upper Mount Marion Formation (in eastern NY) and an upper Oatka Creek Formation (in central and western NY) in a publication by Ver Straeten and others (in prep). Union Springs Formation will incorporate three members across NY: The Bakoven Member (geographically extended across the State of NY), the Stony Hollow Member (restricted), and the Hurley Member (new). The Hurley underlies the Cherry Valley Member at the base of the laterally equivalent Mount Marion and Oatka Creek Formations. By extending the Cherry Valley across the State, it now includes strata formerly assigned to the upper part of the Stony Hollow Member. The revised Cherry Valley is composed of two lithosomes; an eastern sand-dominated facies and a central to western carbonate-dominated facies. Strata above the Cherry Valley in the Oatka Creek remain unnamed, though they bear some resemblance to the Chittenango Shale Member of the Mount Marion Formation of west-central NY (Ver Straeten and others, 1994). Otsego - Mount Marion Formation of Hamilton Group is divided into Berne and overlying Otsego Members. The boundary between the two members is revised in this report. The base of the Otsego is placed at the base of a coral-brachiopod biostrome, the lowest rugose coral in a massive sandstone or the top of the massive sandstone (in the absence of corals). In the absence of both, the base is placed at the lowest shell-bed-rich shales that overlie an 8.0-m-thick package of thin sandstones and shales. The base is somewhat diachronous due to local erosive beveling. Formal names are proposed here for four key beds within the Formation: the Dave Elliott occurs in the upper part of the Berne Member; the Halihan Hill Bed marks the base of the Otsego; and the Katsbaan and Timmerman Hill Beds occur in the lower part of the Otsego (Ver Straeten, 1994).|
Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic Map of New York State, consisting of 5 sheets: Niagara, Finger Lakes, Hudson-Mohawk, Adirondack, and Lower Hudson, New York State Museum and Science Service, Map and Chart Series No. 15, scale 1:250,000.
Harris, A.G., Stamm, N.R., Weary, D.J., Repetski, J.E., Stamm, R.G. and Parker, R.A., 1994, Conodont color alteration index (CAI) map and conodont-based age determinations for the Winchester 30' x 60' quadrangle and adjacent area, Virginia, West Virginia, and Maryland: U.S. Geological Survey Miscellaneous Field Studies Map, MF-2239, 40 p., 1 sheet, scale 1:100,000.
de Witt, Wallace, Jr., Roen, J.B. and Wallace, L.G., 1993, Stratigraphy of Devonian black shales and associated rocks in the Appalachian basin, IN Roen, J.B., and Kepferle, R.C., eds., Petroleum geology of the Devonian and Mississippian black shale of eastern North America: U.S. Geological Survey Bulletin, 1909-B, p. B1-B57.
Ver Straeten, C.A., Griffing, D.H. and Brett, C.E., 1994, The lower part of the Middle Devonian Marcellus "Shale", central to western New York State; stratigraphy and depositional history, IN Brett, C.E., and Scatterday, James, eds., Field trip guidebook: New York State Geological Association Guidebook, no. 66, 66th Annual Meeting, Rochester, NY, p. 271-321.
Ver Straeten, C.A., 1994, Microstratigraphy and depositional environments of a Middle Devonian foreland basin; Berne and Otsego Members, Mount Marion Formation, eastern New York, IN Landing, Ed, ed., Studies in stratigraphy and paleontology in honor of Donald W. Fisher: New York State Museum Bulletin, no. 481, p. 367-380.
USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/
|Counties||Herkimer - Madison - Oneida - Otsego - Schoharie|