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Hornblende gabbro

Hornblende gabbro.
State New Hampshire
Name Hornblende gabbro
Geologic age Late Ordovician
Comments Part of the Oliverian Plutonic Suite (Late Ordovician) - Pink, weakly to moderately foliated, locally porphyritic biotite granitoids found in mantled gneiss domes. Mafic varieties contain hornblends. Variably metamorphosed up to amphibolite facies.
Primary rock type gabbro
Secondary rock type
Other rock types
Lithologic constituents
Major
Igneous > Plutonic > Gabbroic > Gabbro (Pluton)hornblende gabbro
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.
Counties Grafton