| State | New Hampshire |
|---|---|
| Name | Hornblende (or alkalic amphibole) syenite |
| Geologic age | Jurassic |
| Lithologic constituents | Major
Igneous > Plutonic > Syenitic > Syenite (Pluton)hornblende (or alkalic amphibole) syenite
|
| 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). Hart Ledge pluton of White Mountain Plutonic-Volcanic Suite, 136+/-6 K/Ar, hornblende (Western Geophysical Co., in NH024). 168+/-4 and 163+/-5 K/Ar, biotite per NH023. |
| 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.Hatch, N.L., and Moench, R.H., 1984 [1985], Bedrock geologic map of the wilderness and roadless areas of the White Mountain National Forest, Coos, Carroll, and Grafton counties, New Hampshire: U.S. Geological Survey Miscellaneous Field Studies Map MF-1594-A, scale 1:125,000.https://pubs.er.usgs.gov/publication/mf1594A |
| NGMDB product | |
| Counties | Carroll - Coos - Grafton |