State | New Jersey |
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Name | Shawangunk Formation |
Geologic age | Middle and Lower Silurian |
Lithologic constituents |
Major
Sedimentary > Clastic > Conglomerate (Bed)Pebble conglomerate having well rounded grains, some of which are limonite stained. Conglomerate consists of matrix-supported quartz and subordinate shale pebbles as long as 5 cm (2 in.) in poorly to well-sorted, planar tabular to trough crossbedded sandstone. Lower part is quartz-pebble conglomerate, which is matrix-supported, poorly to well sorted, cross to planar bedded. Clasts are primarily quartz and sparse dark-gray argillite and black chert.
Sedimentary > Clastic > Sandstone (Bed)Upper part is medium- to medium-dark-gray, or dark-greenish-gray, medium- to thick-bedded sandstone. Grains are well rounded and moderately to well sorted. Contains sparse graphite flakes. Lower part is light- to medium-gray to light-olive-gray, thin- to thick-bedded quartz and feldspathic sandstone. Sandstone is feldspathic and locally approaches an arkose in compostion.
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)Local black to dark-greenish-gray, thin-bedded shale near upper contact. Middle part, occurring in southwest and sporadically in northeast, is light- to medium-dark-gray, greenish-gray, interbedded thin- to medium-bedded, planar tabular to trough cross-bedded shale and sandstone.
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References | Dalton, R.F., Herman, G.C., Monteverde, D.H., Pristas, R.S., Sugarman, P.J., and Volkert, R.A., 1999, New Jersey Department of Environmental Protection, Bedrock Geology and Topographic Base Maps of New Jersey: New Jersey Geological Survey CD Series CD 00-1; ARC/INFO (v. 7.1), scale 1:100,000.Drake, Avery A. Jr.,Volkert, Richard, A., Monteverde, Donald H., Herman, Gregory C., Houghton,Hugh F., Parker, Ronald A., and Dalton, Richard F., 1996, Bedrock Geologic Map of Northern New Jersey: U.S. Geological Survey Miscellanenous Investigations Map I-2540-A, 4 cross sections, 2 sheets, size 56x40; 58x41, scale 1:100.000.https://pubs.er.usgs.gov/publication/i2540A Epstein, J.B., and Epstein, A.G., 1972, The Shawangunk Formation (Upper Ordovician (?) to Middle Silurian) in eastern Pennsylvania: U.S. Geological Survey Professional Paper 744, 45 p.https://pubs.er.usgs.gov/publication/pp744 Mather, W.W., 1840, Fourth annual report of the first geological district of the State of New York: New York Geological Survey Annual Report 4, p. 209-258. |
NGMDB product | |
Counties | Sussex - Warren |