LATE QUATERNARY RELATIVE SEA-LEVEL CHANGE IN THE WESTERN GULF OF MAINE - EVIDENCE FOR A MIGRATING GLACIAL FOREBULGE

New radiocarbon-dated cores obtained by Vibracorers in the western Gul f of Maine confirm that a short-lived, relative sea-level lowstand of similar to-55 m occurred at 11-10.5 ka. These cores and younger salt-m arsh data also reveal that rates of transgression varied throughout th e Holocene, probably due to local variations in glacial isostasy. The isostatic component is resolved by subtracting published approximation s of eustatic sea level from our well-determined observations of local relative sea level. A large peek in the isostatic curve coincides wit h the lowstand and is interpreted as a forebulge 20-25 m in amplitude. Forebulge migration is estimated at 7-11 km/100 yr, based on the timi ng of lowstands across the region.