Bedrock geologic map of the Nashua South quadrangle, Hillsborough County, New Hampshire, and Middlesex County, Massachusetts

Walsh, Gregory J.; Jahns, Richard H.; Aleinikoff, John N.

Abstract:

The bedrock geology of the 7.5-minute Nashua South quadrangle consists primarily of deformed Silurian metasedimentary rocks of the Berwick Formation. The metasedimentary rocks are intruded by a Late Silurian to Early Devonian diorite-gabbro suite, Devonian rocks of the Ayer Granodiorite, Devonian granitic rocks of the New Hampshire Plutonic Suite including pegmatite and the Chelmsford Granite, and Jurassic diabase dikes. The bedrock geology was mapped to study the tectonic history of the area and to provide a framework for ongoing hydrogeologic characterization of the fractured bedrock of Massachusetts and New Hampshire. This report presents mapping by G.J. Walsh and R.H. Jahns and zircon U-Pb geochronology by J.N. Aleinikoff. The complete report consists of a map, text pamphlet, and GIS database. The map and text pamphlet are only available as downloadable files (see frame at right). The GIS database is available for download in ESRI^TM shapefile and Google Earth^TM formats, and includes contacts of bedrock geologic units, faults, outcrops, structural geologic information, photographs, and a three-dimensional model.

Genre:

USGS Numbered Series

ProdID:

70042688

Citation Author:

Walsh, Gregory J.; Jahns, Richard H.; Aleinikoff, John N.

Citation Contributing Office:

Eastern Geology and Paleoclimate Science Center

Citation Datum:

1927 North American Datum

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Citation Language:

English

Citation Larger Work Title:

Citation LatN:

42.750

Citation LatS:

42.625

Citation LonE:

-71.375

Citation LonW:

-71.500

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Citation Phsyical Description:

Pamphlet: iv, 31 p.; 1 Map 29.72 x 37.38 inches; Downloads Directory

Citation Projection:

Polyconic projection

Citation Public Comments:

Prepared in cooperation with the Commonwealth of Massachusetts, Massachusetts Geological Survey and the State of New Hampshire, New Hampshire Geological Survey

Citation Publisher:

U.S. Geological Survey

Citation Series:

Scientific Investigations Map

Citation Series Code:

SIM

Citation Series Number:

3200

Citation Search Results Text:

Bedrock geologic map of the Nashua South quadrangle, Hillsborough County, New Hampshire, and Middlesex County, Massachusetts; 2013; SIM; 3200; Walsh, Gregory J.; Jahns, Richard H.; Aleinikoff, John N.