U.S. mid-Atlantic margin records provide constraints on interpretations of global sea-level and deep-sea isotopic records. Based on our scaling of oxygen isotopic records, we predict preservation of strata only during peak interglacials (e.g., 5e, 11) back through the Pliocene. Previous studies in Virginia and the Carolinas suggest much higher sea level than today during the early Pliocene (35±15m); the absence of Pliocene strata in New Jersey and Delaware suggest either sea-level lower than modern or uplift of this region relative to Virginia and the Carolinas. Backstripping of Virginia records suggest a maximum eustatic highstand less than 20 m during the early Pliocene consistent with our scaling of deep-sea isotope records. The margin was largely in hiatus from ca. 2 Ma to stage 5e (125 ka) suggesting sea-levels below present; two likely exceptions were ca. 400 ka and ca. 1 Ma highstands that probably correlate with stages 11 and 31 mega-interglacials. Stages 5e and the Holocene are recorded onshore in New Jersey, whereas other late Pleistocene stages are only found offshore. The late Pleistocene sea-level record from the U.S. middle Atlantic margin is similar to records from New Guinea, Barbados, Araki, and the Red Sea for stages 1, 2, 4, 5e, and 6; large differences exist among records for MIC 3, with smaller differences in MIC5a and-5c. Holocene sea-level records from the Mid-Atlantic region show surprising uniformity considering different proximities to the peripheral bulge, with a relative rise throughout the region of ~1.7-1.9 mm/y since ~5000 yBP. Correcting for geoidal subsidence, the U.S. east coast records suggest a global sea-level (eustatic) rise of ~0.8 mm/y since 5000 yBP. Comparison with other records provides a best estimate of pre-anthropogenic global sea-level rise of 0.8±0.3 mm/y from 5000 until ~1750 AD, indicating that anthropogenic influences are far larger than the natural rise.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 0726 Ice sheets;
- 1222 Ocean monitoring with geodetic techniques (1225;
- 1621 Cryospheric change (0776);
- 1641 Sea level change (1222;