Stratigraphy of the Cretaceous/Paleogene (K/Pg) boundary at the Global Stratotype Section and Point (GSSP) in El Kef, Tunisia: New insights from the El Kef Coring Project

The Cretaceous/Paleogene (K/Pg) boundary is marked by one of the largest mass extinctions in Earth’s history, with geological evidence for this event being expressed hundreds locations worldwide. An extensively studied section located near El Kef, northwestern Tunisia, characterized classic iridium-rich K/Pg layer, abundant and well-preserved microfossils, apparently continuous sedimentation throughout early Danian no previously described structural complication. These features led to its designation 1991 as Global Stratigraphic Section Point (GSSP) base (i.e., boundary). However, outcrop has become weathered, “golden spike” marking GSSP difficult locate. Therefore, Kef Coring Project aimed provide a record unweathered sediments across transition cores recovered from five rotary-drilled holes close GSSP. Here, we present new, high-resolution lithologic, biostratigraphic, geochemical data these cores. stratigraphic successions each hole (all drilled within ∼75 m another) are unexpectedly different, identified formerly unknown unconformity planktic foraminiferal biozone P1b. Our results that at was not or free complication thought. Despite challenges, new composite an age model correlated orbitally tuned Walvis Ridge, South Atlantic Ocean, which critical placing paleoenvironmental paleoecological records global context.