Sea-level records at ~80 ka from tectonically stable platforms: Florida and Bermuda

Abstract

Studies from tectonically active coasts on New Guinea and Barbados have suggested that sea level at ∼ 80 ka was significantly lower than present, whereas data from the Atlantic and Pacific coasts of North America indicate an ∼ 80 ka sea level close to that of the present. We determined ages of corals from a shallow submerged reef off the Florida Keys and an emergent marine deposit on Bermuda. Both localities are on tectonically stable platforms distant from plate boundaries. Uranium-series ages show that corals at both localities grew during the ∼80 ka sea-level highstand, and geologic data show that sea level at that time was no lower than 7–9 m below present (Florida) and may have been 1–2 m above present (Bermuda). The ice-volume discrepancy of the 80 ka sea-level estimates is greater than the volume of the Greenland or West Antarctic ice sheets. Comparison of our ages with high-latitude insolation values indicates that the sea-level stand near the present at ∼80 ka could have been orbitally forced.