Mount Tom road cut, Exeter, Washington Co., Rhode Island, USA
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|Latitude & Longitude (WGS84):||41° 34' 28'' North , 71° 44' 7'' West|
|Latitude & Longitude (decimal):||41.57453,-71.73548|
|Köppen climate type:||Cfb : Temperate oceanic climate|
Road cut, east of crest.
7 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Famennian - Frasnian|
358.9 - 382.7 Ma
|Scituate Igneous Suite - granite|
Age: Late Devonian (358.9 - 382.7 Ma)
Stratigraphic Name: Scituate Igneous Suite
Description: Gray to pink, coarse-grained, porphyritic to subporphyritic subsolvus granite (phenocrysts of perthite, microcline, and plagioclase). Contains microcline, perthite, plagioclase, quartz, and accessory biotite, hornblende, allanite, zircon, apatite, sphene, fluorite, and opaque minerals; minor garnet is present in some varieties; some secondary muscovite, calcite, and epidote. Ovoid clots of mafic and accessory minerals are locally prominent. Some rock is massive, but most is commonly lineated and foliated, especially in the west and south near the Hope Valley shear zone. Includes most rock mapped formerly as Scituate Granite Gneiss, and some rock mapped as Hope Valley Alaskite Gneiss.
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.
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. 
541 - 1000 Ma
|Neoproterozoic crystalline metamorphic rocks|
Age: Neoproterozoic (541 - 1000 Ma)
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.