Mineral Resources On-Line Spatial Data
Mineral Resources > Online Spatial Data > Geology > by state > Massachusetts
|Original map label||Dmg|
|Comments||Part of Connecticut Valley Belt (Silurian and Devonian Rocks) Secondary unit description per MA005 as reported in USGS Geologic Names lexicon (ref. MA024): At Glendale Falls, Middlefield Granite interfingers with Early Ordovician or older Moretown Formation. The granite contains abundant xenoliths of pelitic and mafic schist typical of the Moretown. It is authors' interpretation that the Moretown was deformed and metamorphosed before the intrusion of the Middlefield Granite and that later deformation after intrusion affected both the granite and the schist. Zircons separated from the Middlefield are dated at 447+/3 Ma [Late Ordovician] by evaporation analysis. Age is consistent with interpretation that Middlefield was post-Taconian and pre- or early syn-Acadian (Karabinos and Williamson, 1994).|
|Primary rock type||granite|
|Secondary rock type|
|Other rock types|
Igneous > Plutonic > Granitic > GraniteModerately foliated, biotite-muscovite granite with microcline megacrysts.
Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.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||Hampden - Hampshire|
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