Ordovician granite

Ordovician biotite granite
State Maine
Name Ordovician granite
Geologic age Ordovician
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Granitebiotite granite; U - Unmetamorphosed
Comments AB - Medium rank amphibolite facies; Protolith W - Mafic to felsic volcanic rocks
Stratigraphic units includes: 39 - Adamstown pluton (ME097, ME098, ME089).
References

Osberg, P.H., Hussey, A.M., and Boone, G.M., 1985, Bedrock geologic map of Maine: Maine Geological Survey, Dept. of Conserv., scale 1:500,000.

Zartman, R.E., Hurley, P.M., Kruger, H.W., and Giletti, B.J., 1970, A Permian disturbance of K-Ar radiometric ages in New England: its occurrence and causes: Geol. Soc. Amer., Bull., v. 81, p. 3359-3374.

Aleinikoff, J., 1984, Carboniferous U-Pb age for the Sebago batholith, southwestern Maine: Geol. Soc. Amer., Abs. with Prog., v. 16, p. 1.

Lyons, J.B., Zartman, R.E., and Aleinikoff, J.N., 1983, U-Pb ages of zircons from the Ordovician Highlandcroft plutonic suite and Silurian intrusives: Geol. Soc. Amer., Abs. with Prog., v. 15, p. 187.

NGMDB product
Counties Franklin - Oxford - Somerset