| State | New Hampshire |
|---|---|
| Name | Lower part of Rangeley Formation |
| Geologic age | Lower Silurian (Llandoverian) |
| Lithologic constituents |
Major
Metamorphic > Metasedimentary > Metaclasticgray, thinly laminated (5-25 mm) metapelite with local lentils of turbidites and thin quartz conglomerates
Minor
Sedimentary > Clastic > Conglomerategray, thinly laminated (5-25 mm) metapelite with local lentils of turbidites and thin quartz conglomerates
Incidental
Metamorphic > Metasedimentary > Calc-silicate-rocksparse calc-silicate pods and coticule
|
| Comments | Part of the Central Maine Composite Terrane (Central Maine Trough) - Variably metamorphosed sedimentary and volcanic rocks of greenschist to granulite facies, locally migmatized. Area includes structural belts between the Monroe fault on the west and the Campbell Hill fault on the east; that is, the Bronson Hill anticlinorium, Piedmont allochthon, Kearsarge-central Maine synclinorium, central New Hampshire anticlinorium, and Rochester-Lebanon (Maine) antiformal synclinorium. Granite sill, Gilmanton quadrangle (point within formation): 359+/-? U/Pb, monazite per NH030. Granite pegmatite, Suncook quadrangle (point within formation) 375+/-? U/Pb per NH030. |
| 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 Eusden, J.D., Jr., and Barreiro, Barbara, 1988, The timing of peak high-grade metamorphism in central-eastern New England: Maritime Sediments and Atlantic Geology, v. 24, p. 241-255. |
| NGMDB product | |
| Counties | Belknap - Carroll - Cheshire - Grafton - Hillsborough - Merrimack - Strafford - Sullivan |