New Insights into the Campeche Escarpment Post-Chicxulub Impact Using Multibeam Echo Sounder (MBES) Bathymetry and Backscatter Data

Multibeam Echo Sounder (MBES) bathymetry and backscatter data from the 2014 R/V Falkor survey are used to define the K-Pg boundary outcropping on the Campeche escarpment and to characterize large-scale erosional processes on the Campeche shelf. We delineate the escarpment into four geomorphic provinces based on submarine canyon density and morphology, as well as pronounced geomorphological differences formed in response to erosional processes along-strike of the Campeche Escarpment. Large-scale retrogressive-appearing erosion has left high-angle breaks where large slabs of sediment have eroded the escarpment edge, giving the slope a terraced appearance. This slab erosion reveals higher backscatter intensity material overlain with remnants of lower backscatter intensity sediments within the slide scar. We infer the high intensity backscatter material to be carbonate layers on which slab erosion occurred. The most prominent high-intensity backscatter layer is interpreted to be carbonate unit that identifies the K-Pg boundary layer previously reported by Paull et al. (2014) based on a steep bathymetric change and constrained by cores from DSDP Sites 86 and 94. Upslope, high intensity backscatter layers are inferred to represent post-impact carbonates that infilled the basin flank after the Chicxulub bolide impact. Lower intensity backscatter material is inferred to be fine-grained Cenozoic sediment drape. The stark contrast observed in MBES backscatter data between high intensity carbonate material and lower intensity sediments refines and constrains the location of the K-Pg boundary layer exposed along the Campeche escarpment and provides new insights into the carbonate platform post-bolide impact evolution as observed in the erosional styles of the Campeche escarpment.