Unit symbol: | Jk |
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Age range | Upper to Middle Jurassic (174.1 to 152.1 Ma) |
Lithology: | Sedimentary |
Group name: | Graywacke of Kulukak Bay of Hoare and Coonrad (1978) |
Source map | Wilson, F.H., Mohadjer, Solmaz, Labay, K.A., and Shew, Nora, 2006, Digital datasets for geologic map by Wilson, F.H., Blodgett, R.B., Blome, C.D., Mohadjer, Solmaz, Preller, C.C., Klimasauskas, E.P., Gamble, B.M., and Coonrad, W.L.—Preliminary Integrated Geologic Map Databases for the United States: Digital Data for the Reconnaissance Bedrock Geologic Map for the Northern Alaska Peninsula area, Southwest Alaska: U.S. Geological Survey Open File Report 2006-1303, on-line only. http://pubs.usgs.gov/of/2006/1303/ |
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Symbol | Jk |
Unit name | Graywacke of Kulukak Bay |
Description | A thick marine sedimentary unit referred to as "Weary graywacke" by Hoare and others, 1975. Mapped in the eastern part of the quadrangle by correlation with unit KJs of the adjacent Iliamna quadrangle. Typically consists of dark green or gray massive sandstone, although coarse pebble conglomerate is locally present. Locally hornfelsed. On final map, rocks in eastern part of quadrangle assigned to the Koksetna River sequence of Wallace and others (1989), NSA = 2855 |
Lithology | Sedimentary |
Label | Jkw |
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Description | Graywacke of Kulukak Bay (Weary Graywacke) |
Geologic age | Middle-Jurassic to Kimmeridgian |
Geologic setting | Sedimentary, slope-and-deep-water |
Lithology | Form | Importance |
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Graywacke < Sandstone < Clastic < Sedimentary | Bed | Major |
Siltstone < Clastic < Sedimentary | Bed | Indeterminate, major |
Conglomerate < Clastic < Sedimentary | Bed | Incidental |
Black-shale < Shale < Mudstone < Clastic < Sedimentary | Bed | Incidental |