Mineral Resources On-Line Spatial Data
Mineral Resources > Online Spatial Data > Geology > by state > Massachusetts
|Geologic age||Lower Devonian|
|Original map label||De|
|Comments||Part of Connecticut Valley Belt (Silurian and Devonian Rocks) Secondary unit description per MA006 as reported in the USGS Geologic Names lexicon (ref. MA024): Erving Formation in its type area consists of gray, well-bedded fine-grained, quartz-plagioclase-biotite granulite with very thin to thick beds of muscovite-biotite schist. Second most abundant rock type is hornblende-andesine-epidote-sphene amphibolite; occurs west of Pelham dome, as well as in areas around Quabbin Hill, Wilbraham, Whately, and Leeds. Pink coticule granulite occurs within main granulite bodies, usually within 1 to 2 m of contact with amphibolite; common in type area, as well as near Leverett and near Quabbin Hill on shores of Quabbin Reservoir. Near base of formation in Wilbraham area, includes a unit of interlayered amphibolite and gray to rusty schist. In most areas, Erving is highest exposed unit, except in Wilbraham and Whately areas where it is overlain by Waits River and Gile Mountain Formations, respectively. Thicknesses vary from 200 to 900 m. Age is Devonian in this report (Hatch and others, 1988).|
|Primary rock type||granofels|
|Secondary rock type||mica schist|
|Other rock types||amphibolite|
Metamorphic > Granoblastic > Granofelsbiotite-plagioclase granofels; calc-silicate granofels
Metamorphic > Amphiboliteepidote amphibolite
Metamorphic > Schist > Mica-schistminor mica schist
Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.
Zen, E-An (ed.), Goldsmith, R. (comp.), Ratcliffe, N.M. (comp.), Robinson, P. (comp.), Stanley, R.S. (comp.), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.
|Geographic coverage||Franklin - Hampshire|
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