State | Connecticut |
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Name | Brimfield Schist (Includes Hamilton Resevoir Formation) (uncertain) |
Geologic age | Upper? and Middle Ordovician |
Lithologic constituents |
Major
Metamorphic > SchistGray, rusty-weathering, medium- to coarse-grained, interlayered schist and gneiss, composed of oligoclase, quartz, K-feldspar, and biotite, and commonly garnet, sillimanite, graphite, and pyrrhotite. K-feldspar partly as augen 1 to 3 cm across.
Metamorphic > GneissGray, rusty-weathering, medium- to coarse-grained, interlayered schist and gneiss, composed of oligoclase, quartz, K-feldspar, and biotite, and commonly garnet, sillimanite, graphite, and pyrrhotite. K-feldspar partly as augen 1 to 3 cm across; minor layers and lenses of hornblende- and pyroxene-bearing gneiss.
Minor
Metamorphic > Metasedimentary > Calc-silicate-rock
Metamorphic > Amphibolite
|
Comments | Part of Eastern Uplands; Iapetus (Oceanic) Terrane - Merrimack Synclinorium; Brimfield Schist and equivalent formations (includes Tatnic Hill Formation) (Upper? and Middle Ordovician). Same as Obr |
References | Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000. |
NGMDB product | |
Counties | Middlesex - New London - Tolland - Windham |