Geological History of Connecticut
Tectonic History Introduction Paleozoic Era (450-250 million years ago) tectonic plates including Africa and Eurasia collided with the Proto-North American Plate. Super Continent Pangaea was formed Small part of the African Plate (Avalonia) collided with Proto-North America Lapetos Ocean was squeezed out from between the colliding continents Continental Rocks of Proto-North America, Avalonia and oceanic rocks and sediment deformed and metamorphosed into Granite and Gneisses schists (CT D.E.P. 2009) Mountains such as the Appalachians where built
Tectonic History Introduction cont.
Tectonic History Introduction cont.
Tectonic History Introduction cont.
Tectonic History Introduction cont.
Tectonic History Introduction cont. Mesozoic Era (235 million years ago) plate tectonic process reversed Pangaea began to break apart Atlantic Ocean Began to form Avalonia was firmly attached to North America Rift Basins began to form on each side of the breakup The Newark terrain in central Connecticut is the eroded remains of one of these basins Contains 200 million year old sedimentary rocks and intrusions of basalt from lava flows (CT D.E.P. 2009)
Tectonic History Introduction cont.
Tectonic History Introduction cont.
Glacial History Introduction Glaciation played a major roll on how Connecticut is shaped today 24,000 years ago was the last glaciation that covered Connecticut took place The Glacier flowed south until the weather was to warm to support it’s formation Connecticut was covered with ice for about 5000 years
Glacial History Introduction cont. The glacier contained large amounts of rock, sand, and clay (glacial till) Large boulders were displaced (Plucking) When the ice melted these materials were deposited which formed a terminal moraine Terminal Moraine a large pile of rock, sand, and clay piled up at the edge of the glacier, marking the boundary of the glaciers advancement Long Island, Fishers Island, Martha's Vineyard, Nantucket, and Cape Cod were all formed by terminal moraines Terminal Moraine
Glacial History Introduction cont. 21,500 – 17,000 years ago 26,000 – 21,500 years ago 15,500 – 5,000 years ago 17,500-15,500 years ago 5,000 years ago to present
Work Cited http://www.ct.gov/dep/cwp/view.asp?a=2698&q=3232 52&depNav_GID=1707 (2009)