Precambrian gneisses of the Chain Lakes Massif

Precambrian gneisses of the Chain Lakes Massif
State Maine
Name Precambrian gneisses of the Chain Lakes Massif
Geologic age Precambrian
Lithologic constituents
Major
Metamorphic > Gneiss (Greenschist)GS - Greenschist facies; Protolith Y - Basement
Comments Islesboro Formation is of Late Proterozoic age. Consists of interbedded pelite, siltstone and sandstone, limestone and dolomite, conglomerate, rhyolite, and basalt. D.B. Stewart (1990, oral commun.) considers Islesboro to be distal facies of North Haven Greenstone, Ellsworth Schist and schist at Columbia Falls (eastern coastal ME). (ME072) Unit description from USGS GEOLEX website (ME078). GS - Greenschist facies; AA - Low rank amphibolite facies; Protolith Q - Interbedded pelite and sandstone
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.

NGMDB product
Counties Franklin - Oxford - Somerset