| State | Connecticut |
|---|---|
| Name | Holyoke Basalt |
| Geologic age | Lower Jurassic |
| Lithologic constituents | Major
Igneous > Plutonic > Gabbroic > GabbroGreenish-gray to black (weathers bright orange to brown), fine- to coarse-grained, grading from basalt near contacts to gabbro in the interior, composed of pyroxene and plagioclase with accessory opaques and locally olivine or devitrified glass.
Igneous > Volcanic > Mafic-volcanic > BasaltGreenish-gray to black (weathers bright orange to brown), fine- to coarse-grained, grading from basalt near contacts to gabbro in the interior, composed of pyroxene and plagioclase with accessory opaques and locally olivine or devitrified glass.
|
| Comments | Part of Central Lowlands; Newark Terrane - Hartford and Pomperaug Mesozoic Basins. Part of Newark Supergroup (Upper Triassic and Lower Jurassic). Part of ""Meriden Formation"" of Krynine (1950) (Lower Jurassic); CT005. |
| References | Rodgers, John, compiler, 1985, Bedrock Geological Map of Connecticut: Connecticut Geological and Natural History Survey, Hartford, Connecticut, 2 sheets, scale 1:125,000.Krynine, P.D., 1950, Petrology, stratigraphy, and origin of the Triassic sedimentary rocks of Connecticut: Conn. Geol. Nat. History Survey Bull. 73, 239 p. |
| NGMDB product | |
| Counties | Hartford - Litchfield - Middlesex - New Haven |