Bedrock and Glacial History and Geomorphology of Long Island and Southern Connecticut By Drew...

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.