Roxbury Granite Quarry (upper quarry), Mine Hill (Ore Hill), Roxbury, Litchfield Co., Connecticut, USA
|Latitude & Longitude (WGS84):||41° 33' 45'' North , 73° 20' 26'' West|
|Latitude & Longitude (decimal):||41.56250,-73.34083|
|Köppen climate type:||Dfb : Warm-summer humid continental climate|
An intermittently active granite gneiss quarry on Mine Hill sometimes referred to as the "upper quarry" to distinguish it from the Rockside Quarry farther north and on the base of Mine Hill, which is long inactive. Last worked from 1952 to 1961 by Charles Showalter and his son, then by Gino Perone until at least 1982. Bell and Mayfield (1982) mapped the hill and show that 3 of the quartz-siderite veins extend into the upper quarry.
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
3 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.
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|Eifelian - Lochkovian|
387.7 - 419.2 Ma
|Ordovician? granitic gneiss|
Age: Devonian (387.7 - 419.2 Ma)
Description: (Including local terms Ansonia, Mine Hill, "Tyler Lake," "Siscowit") - White, light-gray, buff, or pink, generally foliated granitic gneiss, composed of sodic plagioclase, quartz, microcline, muscovite, and biotite, and locally garnet or sillimanite. Commonly contains numerous inclusions or layers of mica schist and gneiss.
Comments: Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium; Ansonia Gneiss is here referred to as Ansonia leucogranite. On the basis of field and laboratory studies, Ansonia, Beardsley, Pumpkin Ground, and Shelton gneisses, previously considered stratigraphic units, are reinterpreted as plutonic. Ansonia is described as a strongly lineated and moderately foliated, fine-grained, garnet-bearing, biotite-muscovite leucogranite with a well-developed granoblastic texture. Intrudes Beardsley and Pumpkin Ground orthogneisses. Maximum age from zircons is 417+/-1.5 Ma. Conservative interpretation of isotopic data is crystallization between 393 and 419 Ma and therefore, authors assign an age of 406+/-13 Ma (Late Silurian to Early Devonian) to the Ansonia (Sevigny and Hanson, 1993) per CT007.
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.