Orfordville Formation, Post Pond Volcanics (VTOop;0)

Orfordville Formation, Post Pond Volcanics - Greenstone, green chloritic schist interbedded with schistose felsite, quartz-feldspar-sericite schist; fine-grained chloritic, biotitic gneiss, all west of Ammonoosuc fault; mainly amphibolite east of the Ammonoosuc fault.

State	Vermont
Name	Orfordville Formation, Post Pond Volcanics
Geologic age	Ordovician
Original map label	Oop
Comments	Part of Eastern Vermont
Primary rock type	greenstone
Secondary rock type	greenschist
Other rock types	mica schist; biotite gneiss; amphibolite
Lithologic constituents	Minor Metamorphic > Gneissfine-grained chloritic, biotitic gneiss Metamorphic > Schistgreen chloritic schist interbedded with schistose felsite, quartz-feldspar-sericite schist Metamorphic > Metaigneous > Greenstone Metamorphic > Amphibolite
Map references	Nicholson, S.W., Dicken, C.L., Horton, J.D., Foose, M.P., Mueller, J.A.L., and Hon, Rudi, 2006, Preliminary integrated geologic map databases for the United States: Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, Rhode Island, and Vermont: U.S. Geological Survey Open-File Report 2006-1272. [http://pubs.er.usgs.gov/publication/ofr20061272]
Unit references	Doll, C.G., Cady, W.M., Thompson, J.B., Jr., and Billings, M.P., 1961, Centennial Geologic Map of Vermont: Vermont Geological Survey, Miscellaneous Map MISCMAP-01, scale 1:250,000.
Geographic coverage	Orange - Windsor