Trondhjemite and quartz diorite in northern Jefferson dome in Gorham quadrangle (NHOo3B-6;0)

State	New Hampshire
Name	Trondhjemite and quartz diorite in northern Jefferson dome in Gorham quadrangle
Geologic age	Late Ordovician
Original map label	Oo3B-6
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	trondhjemite
Secondary rock type	quartz diorite
Other rock types
Lithologic constituents	Major Igneous > Plutonic > Dioritic > Quartz-diorite (Pluton) Igneous > Plutonic > Granitic > Tonalite > Trondhjemite (Pluton)
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. [http://pubs.er.usgs.gov/publication/ds215]
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.
Geographic coverage	Coos