Raff southeast GSA Presentation March 2017

Raff, J.L., Shawler, J.L., Ciarletta, D.J., Hein, E.A., and Hein, C. J.

Sediment Supply

Storms

Subtle Controls Mod. from Harris, 1992

Modified from Engelhart et al., 2012

Relative sea-level change

Deaton, Hein, and Kirwan, 2016

Western Ridge

Italian Ridge

Little Beach

Revels Island

Western Ridge 973 ± 144 CE

1000 – 1700 CE

Material for radiocarbon analysis….

Somewhere under that water 560 ± 60 years

Dr. Chris Hein (under blanket) Collecting OSL samples

Western Ridge 973 ± 144 CE

Little Beach 1761 ± 139 CE 1876 ± 20 CE

Revels Island 1456 ± 60 CE

Western Ridge 973 ± 144 CE

Little Beach 1761 ± 139 CE 1876 ± 20 CE

Revels Island 1456 ± 60 CE

Western Ridge 973 ± 144 CE Italian Ridge 1740 ± 20 CE

Little Beach 1761 ± 139 CE 1876 ± 20 CE

Revels Island 1456 ± 60 CE

Little Beach

1967

2016

Modified from Richardson, 2012

• Pleistocene highs stabilize and “pin” Holocene barriers • Abundant sediment supply (?) allows the barrier to prograde; young barrier • Recent (last 200 years) shift to a parallel erosional regime