We show that Cenozoic sea-level estimates derived from “backstripping” of Mid-Atlantic margin cores differ by 10-50 m on the 2-10 Myr scale from Global Mean Sea Level (GMSL) estimates using benthic foraminiferal δ18O and accounting for ice-volume variations with Mg/Ca records. Spatial analysis reveals coherent differences in these discrepancies among backstripping sites located onshore New Jersey (NJ), offshore NJ, and onshore south of NJ. These spatial differences have a wavelength that fits mantle dynamic topography, which has influenced the Mid-Atlantic margin over the past 66 Myr. We estimate topographical effects of up to 40 meters in the Eocene onshore NJ, and of up to 25 m in the Miocene offshore NJ.
WHATS NEXT: Schmelz will continue to develop a forward model for evaluating the effects of global mean sea level and tectonics including Mantle Dynamic Topography on the deposition record of the Mid-Atlantic margins Student opportunities include working on comparing model output to 3-D seismic data for the Miocene or the long-term (Jurassic to Holocene) record of the margin.