Porphyritic syenite

Hastingsite or hornblende and (or) hedenbergite are present.
State New Hampshire
Name Porphyritic syenite
Geologic age Jurassic
Lithologic constituents
Major
Igneous > Plutonic > Syenitic > Syenite (Pluton)Porphyritic syenite - Hastingsite or hornblende and (or) hedenbergite are present.
Comments Part of the White Mountain 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). White Mountain Plutonic-Volcanic Suite, ALL ages per NH023. Carrigain Syenite Porphyry = 193+/-2 Rb/Sr. Albany Porphyritic Quartz Syenite = 170+/-3 Rb/Sr and 179+/-5 K/Ar. Mount Garfield Porphyritic Quartz Syenite = 201+/-6 and 193+/-6 K/Ar
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, 2 sheets, scale 1:250,000.

https://ngmdb.usgs.gov/Prodesc/proddesc_37338.htm

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.

Eby, G.N., Krueger, H.M., and Creasy, J.W., 1992, Geology, geochronology, and geochemistry of the White Mountain batholith, New Hampshire, in Puffer, J.H., and Ragland, P.C., eds., Eastern North American Mesozoic magmatism: Geological Society of America Special Paper 268, p. 379-397.

NGMDB product
Counties Belknap - Carroll - Grafton