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College Hill Granite Gneiss
Light-gray to medium-dark-gray, porphyritic biotite-microcline-perthite granodioritic gneiss and pegmatite. Strongly deformed, lineated, and saturated with less deformed later pegmatite; grades outward into a migmatitic border exhibiting decreasing concentration of microcline megacrysts. Forms a single large intrusive mass on College Hill in Jamaica and west of Stratton Mountain; truncates structure in older gneisses. U-Pb zircon TIMS age of 1,244±8 Ma, no. 11 (Ratcliffe and others, 1991; Aleinikoff and others, 2011). Stratton Mountain Intrusive Suite (Middle Mesoproterozoic) (1,244±8 Ma to 1,221±4 Ma). Mount Holly Complex intrusive rocks. Rocks of the Green Mountain and Lincoln Mountain massifs and eastern domes.
State |
Vermont |
Name |
College Hill Granite Gneiss |
Geologic age |
Middle Mesoproterozoic |
Lithologic constituents |
Major
Metamorphic > Metasedimentary > ParagneissLight-gray to medium-dark-gray, porphyritic biotite-microcline-perthite granodioritic gneiss.
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatite
|
References |
Ratcliffe, N.M., Stanley, R.S., Gale., M.H., Thompson, P.J., and Walsh, G.J., 2011, Bedrock geologic map of Vermont: U.S. Geological Survey Scientific Investigations Map 3184, 3 sheets, scale 1:100,000.
https://pubs.er.usgs.gov/publication/sim3184 |
NGMDB product |
|
Counties |
Bennington - Windham
|