Pinewood Adamellite

Light-gray, medium-grained, massive adamellite, composed of microcline, albite, quartz, and muscovite with accessory fluorite. High radioactivity.
State Connecticut
Name Pinewood Adamellite
Geologic age Permian
Lithologic constituents
Major
Igneous > Plutonic > Syenitic > Quartz-monzoniteLight-gray, medium-grained, massive adamellite, composed of microcline, albite, quartz, and muscovite with accessory fluorite. High radioactivity.
Comments Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium. Pinewood is described as a coarse-grained, garnet-bearing, two-mica granite that crops out as a small circular pluton at the northwest margin of the study area. Timing of the Alleghenian Orogeny in southwestern CT is constrained by the Pinewood Adamellite, which has 207Pb/235U ages ranging from 287 to 295 Ma. The monazites provide a crystallization age of 291+/-4 Ma. [Age straddles the Pennsylvanian-Permian boundary.] (Sevigny and Hanson, 1993) per CT007.
References

Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.

Sevigny, J.H. and Hanson, G.N., 1993, Orogenic evolution of the New England Appalachians of southwestern Connecticut: Geological Society of America Bulletin, v. 105, no. 12, p. 1591-1605.

NGMDB product
Counties Fairfield