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Geologic Unit: Nahant
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Map showing publication footprint
  • Usage in publication:
    • Nahant Schist*
  • Modifications:
    • Named
  • Dominant lithology:
    • Schist
  • AAPG geologic province:
    • Midcontinent region
Publication:

Bayley, R.W., 1972, A preliminary report on the geology and gold deposits of the Rochford district, Black Hills, South Dakota, IN Contributions to economic geology: U.S. Geological Survey Bulletin, 1332-A, p. A1-A24, (incl. geologic map, scale 1:24,000) [http://ngmdb.usgs.gov/Prodesc/proddesc_21440.htm]


Summary:

Named as a middle formation of Flag Rock Group (rank raised) for exposures at Nahant, sec 34, T3N, R3E, Lawrence Co, SD in the Midcontinent region, the type locality. Composed of slaty to schistose black graphitic rock. Has no conspicuous bedding. No thickness stated. Very generalized description of lithology. Areal extent beyond report boundaries not discussed. Formerly mapped as unnamed part of Flag Rock Formation. Is contemporaneous with Rapid Creek Greenstone (new) of Flag Rock Group. Overlies Montana Mine Formation (new) of Flag Rock Group. Underlies Rochford Formation (new) of Flag Rock Group. Of middle Precambrian age. Geologic map.

Source: GNU records (USGS DDS-6; Denver GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Nahant Schist
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • Midcontinent region
Publication:

DeWitt, Ed, Redden, J.A., Wilson, A.E., and Buscher, David, 1986, Mineral resource potential and geology of the Black Hills National Forest, South Dakota and Wyoming, with a section on salable commodities by J.S. Dersch: U.S. Geological Survey Bulletin, 1580, 135 p., (incl. geologic map, scale 1:250,000)


Summary:

Mapped in the Rochford area, Pennington Co, SD in the Midcontinent region with Early Proterozoic unit Xsi (Pl. 1). Geologic map.

Source: GNU records (USGS DDS-6; Denver GNULEX).


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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