State | Rhode Island |
---|---|
Name | Hoppin Formation |
Geologic age | Cambrian |
Lithologic constituents |
Major
Sedimentary > Clastic > Sandstone > Arenitequartz arenite
Metamorphic > Metasedimentary > Metaclastic > Argillite
Minor
Sedimentary > Carbonate > Limestone
|
Comments | Part of Esmond-Dedham Subterrane (West Bay Area). Secondary unit description from USGS Geologic Names lexicon (ref. RI013): Hoppin Formation consists of green and red slaty shale, locally containing calcareous nodules, and lenses of red argillaceous limestone; arkosic quartzite (locally conglomeratic) and sandstone occur at base of formation. Nonconformity at base of formation over Dedham Granite is clearly exposed at Hoppin Hill; Early Pennsylvanian Pondville Conglomerate lies with angular unconformity above. Maximum thickness is approx 244 m. Age is Early and Middle Cambrian. Report includes geologic maps, measured sections, and correlation charts. [Chapters A-J in U.S. Geological Survey Professional Paper 1366 are intended as explanations and (or) revisions to 1:250,000-scale MA State bedrock geologic map of Zen and others (1983).] Source: GNU records (USGS DDS-6; Reston GNULEX). |
References | Hermes, O.D. (comp.), Gromet, L.P. (comp.), Murray, D.P. (comp.), Hamidzada, N.A., Skehan, J.W., and Mosher, S., 1994, Bedrock geologic map of Rhode Island: Rhode Island Map Series No. 1, Kingston, Rhode Island, scale 1:100,000.USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/https://ngmdb.usgs.gov/Geolex/search |
NGMDB product | |
Counties | Providence |