Connecticut has a diverse geology as a result of its long geologic history, which includes episodes of continental collisions, mountain building, volcanism, continental rifting, erosion, continental glaciation, and coastal processes.


Map image from the Connecticut Geology page of Wesleyan University.

Early in the Triassic Era, the Iapetus Ocean closed when Proto-North America collided with the landmass Avalonia. This resulted in the formation of the Appalachian Mountains and the supercontinent Pangaea.

Later, during the Jurassic Era, Pangaea rifted apart, forming the Atlantic Ocean, which is still widening due to the formation of new crust at the Mid-Atlantic Ridge. The rifting also formed the Hartford Basin, as a rift valley west of the Eastern Border Fault.

During the Pleistocene Epoch, continental ice sheets moved bedrock and soil generally southward, forming glacial deposits such as till and outwash and features such as moraines, outwash plains, and glacial lakes, including Lake Hitchcock, which is now gone.

The Talcott Mountain Science Center offers a Bedrock Geological Map of Connecticut and a Connecticut Bedrock Geologic Quadrangle Reference to 115 Connecticut bedrock geologic quadrangles, which are each offered as an image.

See also:
Google Earth Community: Long Island Sound
Google Earth Community: Glacial Erratic - Stony Creek Granite Gneiss

In addition, see Google Earth Community: Sleeping Giant Trail Map, Hamden, CT to note the alignment of Sleeping Giant State Park with some of the Early Jurassic basalt lava flows on this map.

The attached KMZ file contains an overlay of a geologic map of Connecticut. The map image was downloaded from the Wesleyan University web site on their Connecticut Geology web page on July 31, 2009.