Hopkinton, Washington Co., Rhode Island, USA
|Latitude & Longitude (WGS84):||41° 28' 35'' North , 71° 45' 9'' West|
|Latitude & Longitude (decimal):||41.47639,-71.75250|
|Köppen climate type:||Cfb : Temperate oceanic climate|
Hopkinton is a town, incorporated in 1757.
Mineral ListMineral list contains entries from the region specified including sub-localities
5 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
541 - 635 Ma
|Sterling Igneous Suite - alaskite gneiss|
Age: Ediacaran (541 - 635 Ma)
Stratigraphic Name: Sterling Plutonic Suite
Description: Pale pink, orange, or gray, fine- to medium-grained granite gneiss, rarely with porphyroclasts of microcline/orthoclase. Composition is granite with generally less than 3% dark minerals. Composed of sodic plagioclase, quartz, microcline/orthoclase, minor biotite, and opaque minerals; minor muscovite (in part secondary), and rare garnet and sphene in some rocks; accessory apatite and zircon; secondary chlorite. Varies from massive to layered. Strongly foliated and locally well lineated. Includes most rock mapped formerly as Hope Valley Alaskite Gneiss.
Comments: Part of Hope Valley Subterrane. Age of 601 +/-5 Ma by U/Pb methods on zircon is reported by Hermes and Zartman (1985) from a sample in RI per RI005. Per printed map: age of rock based on radiometric data from RI005, RI009, and RI012.
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.