Geological History of Connecticut

Paleozoic Era (450-250 million years ago) tectonic plates including Africa and Eurasia collided with the Proto-North American Plate.Super Continent Pangaea was formedSmall part of the African Plate (Avalonia) collided

with Proto-North AmericaLapetos 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

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 reversedPangaea began to break apartAtlantic Ocean Began to formAvalonia was firmly attached to North AmericaRift Basins began to form on each side of the

breakupThe Newark terrain in central Connecticut is the

eroded remains of one of these basinsContains 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.

Tectonic History Introduction cont.

Glaciation played a major roll on how Connecticut is shaped today24,000 years ago was the

last glaciation that covered Connecticut took placeThe 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

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

Glacial History Introduction cont.

Terminal Moraine

Glacial History Introduction cont.

26,000 – 21,500 years ago

21,500 – 17,000 years ago

17,500-15,500 years ago

15,500 – 5,000 years ago

5,000 years ago to present

http://www.ct.gov/dep/cwp/view.asp?a=2698&q=323252&depNav_GID=1707 (2009)

Work Cited