Granite of the Fall River pluton

Light-gray, medium-grained, biotite granite, in part mafic-poor. Gneissic in New Bedford area. Includes Bulgarmarsh Granite (Proterozoic Z). Intrudes Zgs. Fall River pluton of the MA State map (Zen and others, 1983) is here referred to as the Fall River Granite. According to the authors, the change in name is meant to indicate the heterogeneous nature of the granite and the fact that it may consist of more than a single pluton. Included in this unit is the Bulgarmarsh Granite of Fall River and a mass of alaskitic gneiss shown on the State map south of Fall River. No type section is designated. Geologic map shows the Fall River present in the New Bedford area of MA and RI and bounded on the west by the Narragansett Bay Group. The Fall River was dated by Zartman and Naylor (1984) at about 600 Ma (U-Th-Pb zircon) (Murray and others, 1990).
State Massachusetts
Name Granite of the Fall River pluton
Geologic age Proterozoic Z
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granite (Pluton)Light-gray, medium-grained, biotite granite, in part mafic-poor. Gneissic in New Bedford area. Includes Bulgarmarsh Granite.
Comments Part of Milford-Dedham Zone (Tertiary and Older Rocks). Secondary unit description per MA021.
References

Zen, E-An (ed.), Goldsmith, R. (comp.), Ratcliffe, N.M. (comp.), Robinson, P. (comp.), Stanley, R.S. (comp.), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., and Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.

https://pubs.er.usgs.gov/publication/70046713

Murray, D.P., Hermes, O.D. and Dunham, T.S., 1990, The New Bedford area; a preliminary assessment, IN Socci, A.D., Skehan, J.W., and Smith, G.W., eds., Geology of the composite Avalon terrane of southern New England: Geological Society of America Special Paper, 245, p. 155-169.

NGMDB product
Counties Bristol - Plymouth