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  • Usage in publication:
    • Robertstown Formation*
  • Modifications:
    • Named
  • Dominant lithology:
    • Sandstone
    • Schist
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Nelson, A.E., and Gillon, K.A., 1985, Stratigraphic nomenclature in the Richard Russell and Helen thrust sheets, Georgia and North Carolina, IN Stratigraphic notes, 1984: U.S. Geological Survey Bulletin, 1605-A, p. A59-A62.


Summary:

The informal Unicoi Park formation of Gillon (1982) is here named the Robertstown Formation of the Helen Group in the Helen thrust sheet in GA and NC. It consists of thinly layered, coarse-grained feldspathic metasandstone interlayered with mica schist, amphibolite, and pebbly quartz metasandstone, and is characterized by thin, aluminous schist partings between metasandstone beds. The southeast side of the formation is conformable to the adjacent Horton Formation of the Helen Group; it is truncated on the northwest by the Shope Fork fault. Age is tentatively Late Proterozoic to early Paleozoic.

Source: GNU records (USGS DDS-6; Reston 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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