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Rhyolite and fine-grained granite

Rhyolite and fine-grained granite - Includes some ignimbritic caldera-fill and minor intrusive rocks (part of Ossipee Mountain Complex of Kingsley, 1931); also some aphanitic gray, black, or tan quartz-feldspar porphyry.
State New Hampshire
Name Rhyolite and fine-grained granite
Geologic age Cretaceous
Comments Part of the New England-Quebec igneous province of McHone and Butler (1984). Overall, part of the White Mountain Plutonic-Volcanic Suite - Includes Cretaceous alkalic syenite to granitic to gabbroic plutons, minor volcanic rocks, and lamprophyre dikes of the New England-Quebec igneous province of McHone and Butler (1984); also includes Jurassic granite and syenite and less abundant quartz syenite, diorite, gabbro, nepheline syenite, and volcanic rocks of the White Mountain igneous province of McHone and Butler (1984).
Primary rock type rhyolite
Secondary rock type granite
Other rock types ignimbrite; porphyry
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic > Rhyolite
Igneous > Plutonic > Granitic > Granite
Minor
Igneous > Volcanic (Pyroclastic)includes some ignimbritic caldera-fill and minor intrusive rocks
Igneous > Plutonicminor intrusive rocks; also some aphanitic gray, black, or tan quartz-feldspar porphyry.
Map references
Bennett, D. S, , Wittkop, C.A., and Dicken, C.L., 2006 , Bedrock Geologic Map of New Hampshire - A Digital Representation of the Lyons and others 1997 map and ancillary files: U.S. Geological Survey Data Series 215, scale 1:250,000, CD-ROM.
Unit references
Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1997, Bedrock Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey Special Map, 1:250,000, 2 sheets.
McHone, J.G., and Butler, J.R., 1984, Mesozoic igneous provinces of New England and the opening of the North Atlantic Ocean: Geological Society of America Bulletin, v. 95, p. 757-765.
Kingsley, Louise, 1931, Cauldron subsidence of the Ossipee Mountains: American Journal of Science, v. 12, p. 134-167.
Counties Belknap - Carroll - Strafford