Cretaceous-Paleogene boundary deposits at Loma Capiro, central Cuba: Evidence for the Chicxulub impact

Abstract

A newly discovered Upper Cretaceous to lower Paleogene section at Loma Capiro (central Cuba) has provided new evidence for a Cretaceous-Paleogene boundary age for the Chicxulub impact. The studied sediments at Loma Capiro consist of a foraminifera-rich marl and sandstone hemipelagic sequence, and a 9.6-m-thick intercalated clastic complex. Planktic foraminifera indicate an upper Maastrichtian age for the sediments below the clastic complex and a lowermost Danian age for those just above this complex. Small benthic foraminifera from below and above the clastic complex indicate deposition at middle to lower bathyal depths. The fining-upward clastic complex consists of a basal breccia that is overlain by microconglomerates and coarse- to fine-grained sandstones. The clastic complex contains reworked foraminifera from different ages and different paleoenvironments and, toward the top, impact material such as altered microtektites, shocked quartz, terrestrial chondrules, and accretionary lapilli. These microfacies suggest deposition from gravity flows that eroded sediments from upper-slope and shelf settings and redeposited them in deeper bathyal environments. We suggest that the origin of the clastic complex may be linked to the collapse of the Cuban platform, triggered by the Cretaceous-Paleogene impact at Chicxulub.