Impacts, Tsunamis, and the Haitian Cretaceous-Tertiary Boundary Layer

Abstract

The marker bed at the Cretaceous-Tertiary boundary of the Beloc Formation (southern Haiti) contains abundant coarse-grained microtektites and minor amounts of shocked quartz grains in the basal part. The upper part is composed of medium-grained marl with amalgamated microtektite lenses and finer-grained marl lenses disseminated throughout. Field and petrographic observations, and the distribution of planktonic foraminifera suggest that the bed formed from a complex sequence of events. A bolide impact nearby produced microtektites that sett1led to form a nearly pure layer at the base. Vaporized materials with anomalously high extraterrestrial components settled last, along with carbonate sediments. The entire bed became sparsely consolidated. Subsequently, another major disruptive event, perhaps a giant tsunami, partly reworked the initial deposit. Cohesive fragments of the original marker bed mixed with exotic materials were redeposited as lenticular bodies. This process also may have caused further mixing of Cretaceous and Tertiary microfossils, as observed at Beloc and elsewhere.

Caribbean biogeography: molecular evidence for dispersal in West Indian terrestrial vertebrates.

“…The western Caribbean recently has been identified as the probable area of impact (40); this event has been dated to 64 Myr (41). The tsunami resulting from that collision had an estimated height of 2 km and may have been as high as 4-5 km near the impact site (42). When it reached Cuba, it probably was >500 m high (40) and there is evidence that it scoured the southern coast of North America at a height of 50-100 m (43).…”

Chicxulub impactites: Geochemical clues to the precursor rocks

“…The glassy ejecta material investigated in this study (sample WT 1 Beloc) was separated from porous limestones of the WT boundary at Beloc, Haiti (Maurrasse and Sen, 1991;Sigurdsson et al, 1991). This yellow-grey lithology, illustrated in Fig.…”

A spike of woody plant biomarkers in the deep-sea iridium layer at the Cretaceous/Paleogene boundary

“…Haiti was located approximately 700 km south of Chixulub at the end-Cretaceous (Olsson et al, 1997). In this study, we analyzed the stratotype section in Beloc, Haiti (Maurasse and Sen, 1991). In the K/Pg section at Beloc, coarse ejecta, which include spherules and impact glasses, directly overlies uppermost Maastrichtian marlstones, which contain many large planktonic foraminifera (Fig.…”

“…Here, we report as one of the results of this study the dissolved oxygen conditions at Beloc, Haiti. The Caravaca, Agost, and Beloc sections all consist of pelagic pale-gray marls with abundant microfossils (Maurasse and Sen, 1991;Algret and Thomas, 2005).…”