Dry Hill Gneiss

Pink microcline-biotite and microcline-hornblende gneiss containing pink microcline megacrysts and minor quartzite.
State Massachusetts
Name Dry Hill Gneiss
Geologic age Proterozoic Z
Lithologic constituents
Major
Metamorphic > Gneisspink microcline-biotite and microcline-hornblende gneiss
Minor
Metamorphic > Metasedimentary > Metaclastic > Quartzitecontaining pink microcline megacrysts and minor quartzite
Comments Part of Bronson Hill Zone (Ordovician and Older Rocks). Microcline gneiss of the Dry Hill Gneiss in the Pelham dome, a metamorphosed alkali rhyolite, is confirmed to be Late Proterozoic with an age of 613+/-3 Ma (Tucker and Robinson, 1990) per MA015.
References

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., and Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.

https://pubs.er.usgs.gov/publication/70046713

Tucker, R.D. and Robinson, Peter, 1990, Age and setting of the Bronson Hill magmatic arc; a re-evaluation based on U-Pb zircon ages in southern New England: Geological Society of America Bulletin, v. 102, no. 10, p. 1404-1419.

NGMDB product
Counties Franklin - Hampshire