USGS Visual Identifier
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Geologic Unit: Mattapan

Mattapan Volcanic Complex (MA*)

Proterozoic, Late*
Geologic Province:
New England province*

Areal Extent:

Type Locality:
Named from exposures in Mattapan, Dorchester district of Boston, MA (LaForge, 1917).

Twin Pine and High Rock Tuffs (MA)

Unit Name History:
Named (LaForge, 1917).
Age modified (Kaye and Zartman, 1980).
Age modified; Isotopic dating (Goldsmith and others, 1982).
MA State Geol. Map usage (Zen, 1983).
Members named; Isotopic dating (Thompson and Hermes, 1990).
Overview; Age modified; Isotopic dating (Goldsmith, 1991).

Note: If you need more information, please contact Nancy Stamm (
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
Database project personnel
Last modified: 15-Jan-2013