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Bedrock and Glacial History and Geomorphology of Long Island and
Southern Connecticut
By Drew Martzolf
Coastal Connecticut & Long Island• High economic importance• Home to millions of people• Significant ecological value• Current threats:– Coastal erosion– Rising sea levels– Pollution
Formation of the Continent
From: http://www.jamestown-ri.info/acadian.htm
Taconic orogeny
Formation of the ContinentAcadian orogeny
From: http://www.lisrc.uconn.edu/lisrc/geology.asp?p2=History&p3=glhct
Formation of the Continent
From: http://www.lisrc.uconn.edu/lisrc/geology.asp?p2=History&p3=glhct
Alleghenian orogeny
Glacial History• Manetto stage
– Manetto gravel fluvially deposited
• Jameco stage– Jameco gravel deposited in northeast of island
• Manhasset stage– Montauk and Hempstead Formations deposited
• Wisconsinan stage– Ronkonkoma moraine
From: http://pubs.usgs.gov/fs/FS-008-99/html/CT_fig04.html
Formation of Long Island Sound
Original postglacial basin was Glacial Lake Connecticut, dammed in by the moraines of Long Island; water drained to west. Rising sea levels allowed salt water to flood back into basin, followed by erosion to open access from the eastern end to the open ocean.