USGS Visual Identifier
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Geologic Unit: Newburyport

Newburyport Complex (MA*,NH*)

Silurian, Late*

Geologic Province:
New England province*

Areal Extent:

Type Locality:
Newburyport, Essex Co., northeastern MA (Emerson, 1917).

Unit Name History:
[Please note: only the 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.]
Named Newburyport Quartz Diorite (Emerson, 1917).
Age modified (LaForge, 1932).
Extended into NH; Age modified (Billings, 1955).
Age modified (Billings, 1956; Chute, 1966).
Assigned to /Hillsboro plutonic series; Age modified (Novotny, 1969).
Age modified (Chute, 1969; Gates and others, 1969; Zartman and others, 1970; Castle and others, 1976).
Revised to Newburyport Complex; Age modified; Isotopic dating (Goldsmith and others, 1982).
MA State Geol. Map usage (Zen and others, 1983).
Age modified; Isotopic dating (Zartman and Naylor, 1984).
Revised; Areal limits; Isotopic dating (Wones and Goldsmith, 1991).
NH State Geol. Map usage; Age modified; Isotopic dating (Lyons and others, 1997).

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