Uranium-series coral ages from the US Atlantic Coastal Plain–the “80 ka problem” revisited

摘要: Abstract Uranium series coral ages for emergent units from the passive continental margin US Atlantic Coastal Plain (ACP) suggest sea level above present levels at end of marine oxygen isotope stage (MIS) 5, contradicting age-elevation relations based on isotopic or reef models ice equivalent level. We have reexamined this problem by obtaining high precision 230Th/238U and 231Pa/235U thermal ionization mass spectrometric recently collected carefully cleaned ACP corals, many in situ. recognize samples that show no evidence diagenesis basis uranium composition age concordance. Combining new earlier data, among those close to within range MIS over 85% cluster between 65 85 ka BP. Of corals we analyzed, least concordance 80 85 ka BP, consistent with a 5a correlation. The which these been are all elevations ∼3–5 m few where early 5 (∼125,000 ka BP) obtained. appears record an unusual history relative throughout is also apparent dated Bermuda. speculate related regional (near-to intermediate-field) effects ancestral Laurentide Ice sheets last interglacial shorelines western North Atlantic.