Late Pleistocene Sea Level On The New Jersey Margin: Implications To Eustasy And Deep-sea Temperature

摘要

We assembled and dated a late Pleistocene sea-level record based on sequence stratigraphy from the New Jersey margin and compared it with published records from fossil uplifted coral reefs in New Guinea, Barbados, and Araki Island, as well as a composite sea-level estimate from scaling of Red Sea isotopic values. Radiocarbon dates, amino acid racemization data, and superposition constrain the ages of large (20-80 m) sea-level falls from New Jersey that correlate with Marine Isotope Chrons (MIC) 2,3b, 4,5b, and 6 (the past 130 kyr). The sea-level records for MIC 1, 2,4, 5e, and 6 are similar to those reported from New Guinea, Barbados, Araki, and the Red Sea; some differences exist among records for MIC 3. Our record consistently provides the shallowest sea level estimates for MIC3 (～25-60 m below present); it agrees most closely with the New Guinea record of Chappell (2002; ～35-70 m), but contrasts with deeper estimates provided by Araki (～85-95 m) and the Red Sea (50-90 m). Comparison of eustatic estimates with benthic foraminiferal δ~(18)O records shows that the deep sea cooled -2,5℃ between MIC 5e and 5d (～120-110 ka) and that near freezing conditions persisted until Termination la (14-15 ka). Sea-level variations between MIC 5b and 2 (ca. 90-20 ka) follow a well-accepted 0.1‰/10 m linear variation predicted by ice-growth effects on foraminiferal δ~(18)O values. The pattern of deep-sea cooling follows a previously established hysteresis loop between two stable modes of operation. Cold, near freezing deep-water conditions characterize most of the past 130 kyr punctuated only by two warm intervals (the Holocene/MIC 1 and MIC 5e). We link these variations to changes in Northern Component Water (NCW).