State | Rhode Island |
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Name | Narragansett Pier Plutonic Suite - granite |
Geologic age | Permian |
Lithologic constituents |
Major
Igneous > Plutonic > Granitic > Granitedark-pink to pale-gray, medium-grained equigranular granite; Composed of microcline, oligoclase, quartz, and accessory biotite, magnetite, ilmenite, apatite, sphene, zircon, monazite, apatite, and allanite; muscovite and garnet locally present; secondary chlorite and calcite. Mainly massive, but locally exhibits faint flow foliation.
Minor
Igneous > Plutonic > Granitic > Granodioritewith lesser granodiorite and quartz monzonite
Igneous > Plutonic > Syenitic > Quartz-monzonitewith lesser granodiorite and quartz monzonite
Incidental
Igneous > Plutonic > Granitic > Leucocratic-granitic > PegmatiteCut locally by abundant pegmatite, aplite, and composite aplite-pegmatite of mineralogy similar to the host granite.
Igneous > Plutonic > Granitic > Leucocratic-granitic > ApliteCut locally by abundant pegmatite, aplite, and composite aplite-pegmatite 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 and RI008. |
References | 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D.E., 1981, Petrology of the Narragansett Pier Granite and associated country rocks near Narragansett Bay: unpublished MS thesis, University of Rhode Island, Kingston, 132 p.Zartman, R.E., and Hermes, O.D., 1987, Archean inheritance in zircon from late Paleozoic granites from the Avalon zone of southeastern New England: an African connection: Earth and Planetary Science Letters, v. 82, p. 305-315. |
NGMDB product | |
Counties | Washington |