Mineral Resources On-Line Spatial Data
Mineral Resources > Online Spatial Data > Geology > by state > Rhode Island
|Name||Scituate Igneous Suite - alkali-feldspar granite|
|Original map label||Dsa|
|Comments||Part of Esmond-Dedham Subterrane (West Bay Area) The name Scituate Granite Gneiss is no longer appropriate because the type Scituate of Quinn (1971) at Scituate, RI, has been shown by Hermes and others (1981) and Hermes and Zartman (1985) to be Middle Devonian, based on isotopic age of 373 +/-7 Ma; it is part of an unnamed Devonian alkalic suite. Scituate of type area in central RI described by Quinn (1971) is here renamed Scituate Granite and assigned a Middle Devonian age (Wones and Goldsmith, 1991) per RI004. Per printed map: age of rock based on radiometric data from RI005 and RI009.|
|Primary rock type||alkali-granite (alaskite)|
|Secondary rock type|
|Other rock types|
Igneous > Plutonic > Granitic > Alkali-feldspar-graniteGray to pink, medium- to coarse-grained, porphyritic to subporphyritic alkali-feldspar granite (phenocrysts of perthite). Contains perthite, quartz, and accessory biotite, hornblende, and lesser riebeckite, aegerine, zircon, allanite, sphene, fluorite, and opaque minerals. Plagioclase is sparse to absent. Secondary muscovite, chlorite, and calcite. Ovoid clots of mafic and accessory minerals are locally prominent. Rock is a hypersolvus, mildly peralkaline granite. Fabric ranges from massive to locally lineated and foliated.
Hermes, O.D., Gromet, L.P., Murray, D.P., Hamidzada, N.A., 1994, Geologic Map of Rhode Island, file name = bedrock_shp.zip (870kb) obtained from Rhode Island Geographic Information System, http://www.edc.uri.edu/rigis-spf/Statewide/state.html#geology , shapefile or interchange file, scale 1/100,000.
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.
|Geographic coverage||Kent - Providence - Washington|
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