USGS Visual Identifier
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Geologic Unit: Chelmsford

Usage:
Chelmsford Granite (MA*)
Chelmsford Granite of New Hampshire Plutonic Suite (NH*)

Age:
Devonian, Early*

Geologic Province:
New England province*

Areal Extent:
MA*
NH*

Type Locality:
Not designated. Occurs near Chelmsford, Middlesex Co., northeastern MA.

Unit Name History:
[Please note: only the Robinson (1978), Goldsmith and others (1982), Zen and others (1983), Wones and Goldsmith (1991), and Lyons and others (1997) references include synopses here. The remaining references have yet to be added from the GNC index card files. Until then, feel free to contact us if you would like complete bibliographic citations.]
First used as informal unit (Jahns, 1942).
Formal status; Age modified; Isotopic dating (Lyons and Faul, 1968).
Age modified; Extended into NH; Overview (Robinson, 1978).
Overview; Isotopic dating (Goldsmith and others, 1982).
MA State Geol. Map usage (Zen and others, 1983).
Overview; Isotopic dating (Wones and Goldsmith, 1991).
NH State Geol. Map usage; Revised (Lyons and others, 1997).

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