OESBATHY V1.0 TO V1.011: IMPROVEMENTS INTEGRATED IN THE MODEL PARAMETERIZATIONS

OESBathy is a method for reconstructing global ocean bathymetry in a 0.1°x0.1° resolution. This method combines a simple standard geophysical plate cooling model based on the published ages of the oceanic crust, modeled global oceanic sediment thicknesses, and a generalized sediment wedge model (SWM) representing continental shelf-slope-rise (SSR) structures calibrated at modern heterogeneous continental margins, both active and passive types.

First the depth-to-basement (D2B) is calculated. An isostatically adjusted, multicomponent sediment layer constrained by modern global sediment thickness is added to the D2B. In OESBathy v1.0, the sediment loading was based on a very simple linear extrapolation of sediment densities with 100 m increments, calibrated from 10 different published sediment densities. In the updated version, this part of the sediment model was re-calibrated. A database of sediment densities, with more than 45,000 records, was created from several articles, DSDP, ODP and IODP publications. The revised sediment loading was based on a new parametrization of those sediment densities. Finally, a modeled continental SSR structure was added that completes the bathymetry reconstruction, extending from the ocean crust to the coastlines. The original 3-parameter SWM is also enhanced in OESBathy v1.011 with a detailed systematic study of modern SSR regions that are performed at a higher spatial resolution and with improved statistical parametrization. The bedrock version of ETOPO1 global relief data was used to obtain the modern ocean bathymetry data. In OESBathy v1.011, two more components are added based on published geologic records, a) underwater seamounts and b) large igneous provinces/plateaus.

Here, the final product from OESBathy v1.011 is shown using the Paleocene-Eocene Thermal Boundary (PETM, around 56 Ma) case study. For the PETM case, the final products are: a) a global D2B measurement map; b) global oceanic crust bathymetry maps with the improved multilayer sediment layer; c) global oceanic bathymetry maps with updated SWM and d) global bathymetry maps with underwater seamounts and large igneous provinces/plateaus. Similar maps for other geological times can be produced using this OESBathy v1.011 method provided that ocean crustal age is known.