Soapstone Hill quarries (North Dana soapstone quarries), Petersham, Worcester Co., Massachusetts, USA
|Latitude & Longitude (WGS84):||42° 28' 38'' North , 72° 15' 56'' West|
|Latitude & Longitude (decimal):||42.47722,-72.26556|
|Köppen climate type:||Dfb : Warm-summer humid continental climate|
Two quarries, opened about 1878.
1 valid mineral.
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
|Aeronian - Sandbian|
438.5 - 458.4 Ma
Age: Paleozoic (438.5 - 458.4 Ma)
Stratigraphic Name: Monson Gneiss
Comments: Part of Bronson Hill Zone (Ordovician and Older Rocks). Swanzey, Pauchaug, Monson, and Fourmile Gneisses represent metamorphosed intrusive igneous rocks and yield ages from 454 to 442+3/-2 Ma. Therefore, ages range from early Late through latest Ordovician. Authors suggest that they represent the plutonic root of a calc-alkaline magmatic arc at least 250 km long that was produced partly or entirely on a continental margin in the Late Ordovician. The overlying Ammonoosuc Volcanics and Partridge Formation, rather that resting unconformably on these plagioclase-rich plutonic gneiss, are now known to have had a magmatic history overlapping with them and are approximately the same age (Tucker and Robinson, 1990) per MA015.
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.