USGS Visual Identifier
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Geologic Unit: Shawsheen

Usage:
Shawsheen Gneiss (MA*)

Age:
Precambrian*
Proterozoic, Late*
Ordovician*
Geologic Province:
New England province*


Areal Extent:
MA*



Type Locality:
Belt along northwest side of Shawsheen River, Billerica and Wilmington quads, and in Harold Parker State Forest, Reading quadrangle, Middlesex Co., northeastern MA (Bell and Alvord, 1976).

Unit Name History:
Named (Bell and Alvord, 1976).
Age modified (Goldsmith, 1980).
Isotopic dating (Olszewski, 1980).
MA State Geol. Map usage (Zen and others, 1983).
Historical overview, age discussed (Goldsmith, 1991).

Note: If you need more information, please contact Nancy Stamm (nstamm@usgs.gov).
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

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

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).






U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
URL http://ngmdb.usgs.gov/ngmdb/ngm_catalog.ora.html
Database project personnel
Last modified: 15-Jan-2013