Bethlehem Granodiorite

(Bethlehem Gneiss of Billings, 1955) - Gray, strongly foliated biotite-muscovite granodiorite and associated tonalite and granite.
State New Hampshire
Name Bethlehem Granodiorite
Geologic age Early Devonian
Lithologic constituents
Igneous > Plutonic > Granitic > Granodiorite (Pluton)gray, strongly foliated biotite-muscovite granodiorite
Igneous > Plutonic > Granitic > Granite (Pluton)
Igneous > Plutonic > Granitic > Tonalite (Pluton)
Comments Part of the New Hampshire Plutonic Suite (Late to Early Devonian) - Includes synkinematic and postkinematic granitoids related to the Acadian orogeny. Ages range from 410 to 365 Ma. Moody Ledge Granite displaced by Mount Clough pluton = 435+/-3 U/Pb per NH015 455+/-? U/Pb per J.N. Aleinikoff, oral commun., June 1994. New Hampshire Plutonic Suite: Fairlee pluton = 411+/-4 U/Pb, zircon and 400+/-5 U/Pb, monazite per NH025. Mount Clough pluton = 410+/-5 U/Pb per J.N. Aleinikoff, oral commun., Jan.4, 1989. Bellows Falls pluton = 410-405 U/Pb (T.M. Harrison, quoted by NH036).

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, 2 sheets, scale 1:250,000.

Billings, M.P., 1955, Geologic map of New Hampshire: Washington, D.C., U.S. Geological Survey, scale 1:250,000.

Aleinikoff, J.N., and Moench, R.H., 1987, U-Pb geochronology and Pb isotopic sytematics of plutonic rocks in northern New Hampshire; ensimatic vs. ensialic sources [abs.]: Geological Society of America Abstracts with Programs, v. 19, p. 1-2.

Moench, R.H., and Aleinikoff, J.N., 1987, The Piermont allochthon in northwestern New Hampshire; stratigraphic and isotopic evidence [abs.]: Geological Society of America Abstracts with Programs, v. 19, p. 30.

Spear, F.S., 1989, Relative thermobarometry and metamorphic P-T paths, in Daly, J.S., Cliff, R.A., and Yardley, B.W.D., eds., Evolution of mountain belts: Geological Society of America Special Publication 43, p. 63-81.

NGMDB product
Counties Cheshire - Grafton - Merrimack - Sullivan