|Name||Narragansett Pier Plutonic Suite - leucocratic granite|
Igneous > Plutonic > Granitic > Leucocratic-graniticWhite to gray leucocratic granite composed of microcline, oligoclase, and quartz. Up to 10% accessory muscovite and garnet, with lesser apatite, zircon, and monazite. Biotite and opaque minerals notably sparse or absent.
Igneous > Plutonic > Granitic > Leucocratic-granitic > Aplitelocally exhibits flow foliation caused by alternating layers of pegmatite, aplite, and medium-grained equigranular granite; pegmatitic and aplitic material of mineralogy similar to the host granite.
Metamorphic > MetasedimentaryThe granite contains widespread xenolithic inclusions and screens of metasedimentary rock, some of which are PAnbr; bedding and fabric in the screens generally is oriented parallel to that in the host metasedimentary country rock.
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatitelocally exhibits flow foliation caused by alternating layers of pegmatite, aplite, and medium-grained equigranular granite; pegmatitic and aplitic material of mineralogy similar to the host granite.
|Comments||Part of Avalon Terrane Narragansett Pier Plutonic Suite - intrudes both Hope Valley and Esmond-Dedham subterranes (e.g., stitching pluton). Contains abundant veins of pegmatite too small to be mapped individually. Secondary unit description per RI003. Per printed map: age of rock based on radiometric data from RI007.|
Hermes, O.D. (comp.), Gromet, L.P. (comp.), Murray, D.P. (comp.), Hamidzada, N.A., Skehan, J.W., and Mosher, S., 1994, Bedrock geologic map of Rhode Island: Rhode Island Map Series No. 1, Kingston, Rhode Island, scale 1:100,000.
Hozik, M.J., 1992, Tectonic implications of the brittle fracture history of the Permian Narragansett Pier Granite, Rhode Island, IN Bartholomew, M.J., and others, eds., Basement tectonics 8; Characterization and comparison of ancient and Mesozoic continental margins; proceedings of the eighth international conference on basement tectonics: International Conference on Basement Tectonics Proceedings, no. 8, 8th International Conference, Butte, MT, August, 1988, p. 503-525.
Kocis, D.E., 1981, Petrology of the Narragansett Pier Granite and associated country rocks near Narragansett Bay: unpublished MS thesis, University of Rhode Island, Kingston, 132 p.