The Cretaceous-Paleogene (K-Pg) boundary in the shallow northeastern Mexican foreland basins: Evidence for paleoseismic liquefaction, tsunami deposition, and Chicxulub ejecta

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Understanding the depositional sequence and composition of impact ejecta is critical to correct interpretation of timing and influence of the Chicxulub impact regarding the mass extinctions at the Cretaceous-Paleogene (K-Pg) boundary. Preliminary investigations suggest that the shallow La Popa and Parras foreland basins in northeastern Mexico both feature outstanding, continuous 3D exposures of a Chicxulub ejecta-rich K-Pg boundary event deposit. Our data shows evidence for possibly seismic-induced sediment liquefaction followed by a series of ejecta-bearing mass-flows that may be interpreted as impact-related tsunamideposits. Moreover, silicic and carbonate ejecta textures are excellently preserved and even relict glass spherules are present. Therefore, this project aims to (i) document the sedimentology, mineralogy, and paleontology of the K-Pg event deposit, (ii) investigate the petrology of the Chicxulub ejecta, and (iii) link the K-Pg boundary sequence in the shallow foreland basins to proximal deep-water K-Pg sites in the Gulf of Mexico and the Atlantic. We intend to improve current ejecta distribution-deposition models, reveal the age of Chicxulub regarding the K-Pg boundary, and constrain ejecta origin and formation processes as well as the release of climatically-sensitive gases during the impact.