IS THERE EVIDENCE FOR CRETACEOUS-TERTIARY BOUNDARY AGE DEEP-WATER DEPOSITS IN THE CARIBBEAN AND GULF-OF-MEXICO

Over most of the Gulf of Mexico and Caribbean a hiatus is present betw een the lower upper Maastrichtian and lowermost Tertiary deposits; sed imentation resumed approximately 200 ka (upper zone P1a) after the K-T boundary. Current-bedded volcaniclastic sedimentary rocks at Deep Sea Drilling Project (DSDP) Sites 536 and 540, which were previously inte rpreted as impact-generated megawave deposits of K-T boundary age, are biostratigraphically of pre-K-T boundary age and probably represent t urbidite or gravity-flow deposits. The top 10 to 20 cm of this deposit at Site 536 contains very rare Micula prinsii, the uppermost Maastric htian index taxon, as well as low values of Ir (0.6 pbb) and rare Ni-r ich spinels. These indicate possible reworking of sediments of K-T bou ndary age at the hiatus. Absence of continuous sediment accumulation a cross the K-T boundary in the 16 Gulf of Mexico and Caribbean sections examined prevents their providing evidence of impact-generated megawa ve deposits in this region. Our study indicates that the most complete trans-K-T stratigraphic records may be found in onshore marine sectio ns of Mexico, Cuba, and Haiti. The stratigraphic records of these area s should be investigated further for evidence of impact deposits.