Glacial History of Cape Cod, Nantucket, and Martha’s Vineyard Stefan Sandreuter ‘16 GE354

Outline Formation of Cape Cod, Nantucket and Martha’s Vineyard Regional Deposits Post-Glacial Holocene Processes Summary

Formation of Cape Cod, Nantucket and Martha’s Vineyard Three lobes of glacial ice Fluctuating Ice Front Evidenced by till overlying stratified drift; recessional moraines

Regional Deposits Types of deposits General Stratigraphy Age of Deposits – Cosmogenic Nuclide Dating Mineralogy

Cosmogenic Nuclide Ages Martha’s Vineyard Buzzard’s Bay *Radiocarbon dates put glacial deposits between 24,000 and 21,500 years old.

Post-Glacial Holocene Processes Marine and Aeolian Processes Two periods of Holocene modification – 9,500 – 6,000 B.P – 6,000 B.P. to modern day

Summary Three lobes of ice Fluctuating ice sheet Nantucket and Martha’s Vineyard - terminal moraines of the Laurentide Ice Sheet

Summary Cosmogenic nuclide ages of ~23,000 and 19,000 years from Martha’s Vineyard and Buzzards Bay respectively Subarkose and quartz arenite sands from both outwash plains and beaches Constant marine and aeolian modification

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