PRELIMINARY HIGH-RESOLUTION SUBSURFACE IMAGING (2.3 GHZ GPR) OF EMPLACED FOSSIL TARGETS WITHIN HEAVILY BIOTURBATED GLAUCONITE-RICH K/PG BOUNDARY STRATA, NEW JERSEY, USA

The Cretaceous-Paleogene (K/Pg) mass extinction event was one of the most dramatic biotic crises in Earth history. The Atlantic Coastal Plain (New Jersey, USA) contains heavily bioturbated glauconite-rich shallow marine strata that span this boundary, with a particularly well-exposed section in the Jean & Ric Edelman Fossil Park (EFP; Sewell, NJ). The Upper Cretaceous - Lower Paleocene Hornerstown Formation lies conformably above the Upper Cretaceous (Maastrichtian) Navesink Formation, and contains the Main Fossiliferous Layer (MFL) interpreted to represent an extensive taphocoenosis related to the K/Pg event. To complement paleontological and ichnological investigations, we performed the first subsurface imaging using a super-high-resolution 2.3 GHz ground-penetrating radar (GPR). Our research focused on assessing the viability of GPR imaging for detection of fossil targets (turtle costal, triceratops bone, stingray toothplate) within a heavily bioturbated matrix. These were laterally inserted into trench walls of the lowermost Hornerstown Formation, within 0.3 m of the ground surface, just above the MFL. All three targets were successfully identified in 2-m-long surveys as hyperbolic diffractions within a mottled background. Attenuation of the electromagnetic signal is attributed to iron content of glauconitic marine sections, partial oxidation, variable mud content, and complex fabric dominated by Thalassinoides isp. boxwork. Our study not only demonstrates the viability of non-invasive GPR imaging for locating near-surface anomalies at EFP, but also demonstrates the potential to assess bioturbation intensity, with implications for K/Pg paleoichnology and marine biogeomorphology.