Biotite granodiorite

Biotite granodiorite.
State New Hampshire
Name Biotite granodiorite
Geologic age Late Ordovician
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granodiorite (Pluton)biotite granodiorite
Comments Part of the Oliverian Plutonic Suite (Late Ordovician) - Pink, weakly to moderately foliated, locally porphyritic biotite granitoids found in mantled gneiss domes. Mafic varieties contain hornblends. Variably metamorphosed up to amphibolite facies. Whitefield Gneiss of Oliverian Plutonic Suite = 458+/-8 U/Pb per NH020.
References

Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1997, Bedrock Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey Special Map, 2 sheets, scale 1:250,000.

https://ngmdb.usgs.gov/Prodesc/proddesc_37338.htm

Zartman, R.E., and Leo, G.W., 1985, New radiometric ages on gneisses of the Oliverian domes in New Hampshire and Massachusetts: American Journal of Science, v. 285, p. 267-280.

NGMDB product
Counties Coos - Grafton