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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
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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. • 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)
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=323252&depNav_GID=1707 (2009)