Silurian undifferentiated conglomerates and coarse-grained sandstones

Silurian undifferentiated conglomerates and coarse-grained sandstones, in part of the Allsbury Formation and in part unnamed
State Maine
Name Silurian undifferentiated conglomerates and coarse-grained sandstones
Geologic age Silurian
Lithologic constituents
Major
Sedimentary > Clastic > SandstoneW - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; GS - Greenschist facies; Protolith I - Conglomerate
Sedimentary > Clastic > ConglomerateW - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; GS - Greenschist facies; Protolith I - Conglomerate
Comments Named Berwick gneiss for development at Berwick, York Co., ME. Consists chiefly of graywacke gneiss, but contains clean quartzites, mica schist, and argillite schist and slate. Beds range in thickness from an inch to a few feet. Almost all rocks are moderately fine-grained and delicately banded with colors of dark gray, bluish gray, and brown. Total thickness is undeterminable. The age of the Berwick is unknown, but is probably pre-Carboniferous. (ME062) Unit description from USGS GEOLEX website (ME078). GS - Greenschist facies; E - Epidote-amphibolite facies; Protolith K - Calcareous feldspathic 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 Aroostook - Penobscot