Influence Of Mantle Dynamic Topographical Variations On Us Mid-Atlantic Continental Margin Estimates Of Sea-Level Change

Spatial analysis of discrepancies in sea-level estimates derived from "backstripping" Mid-Atlantic margin cores reveals a coherent signal that can be fit with a 10(3) km wavelength, 45 m amplitude sinusoid that moved across the margin at a rate and direction of motion generally opposite to that of the North American Plate. This signal we observe suggests topographical uplift occurred over much of the Mid-Atlantic region since 35 Ma and may be superimposed upon a longer-wavelength signal of Cenozoic subsidence associated with the subducted Farallon plate passing beneath the Mid-Atlantic margin. Our statistical modeling of Mid-Atlantic margin strata suggests that: (a) Cenozoic subsidence is likely to have occurred, but is very unlikely to have exceeded 100 m in magnitude; and (b) variations in ocean basin volume are likely to have contributed to 39 +/- 24 m (1 sigma) of global-mean geocentric sea-level fall over the past 55 million years.