Neogene Aliostratigraphy in the Gulf of Mexico-Caribbean Area: Integrated Biostratigraphic Evidence

Marle-Pierre Aubry and William A. Berggren

In contrast to some studies which have interpreted the Neogene stratigraphic record of the Gulf of Mexico in terms of successive stratigraphic sequences, we have shown that an allostratigraphic pattern is more appropriate to describe this record. We have also shown that the main unconformities between these allostratigraphic units correspond well with the seismic surfaces (A to F) described by Mitchum (1978). Likewise, we have shown that the Neogene stratigraphic record of Jamaica is also best

described in terms of allostratigraphic units. In both the Gulf of Mexico and Jamaica, the stratigraphic gaps correspond to hiatuses of a few hundred years (<0.5 my) to several million years (6 my or more).

We present the results of our correlation of the Neogene records in Jamaica and the eastern Gulf of Mexico and compare the timing of the hiatuses with that of ice build up on Antarctica as inferred from ^dgr¹⁸O studies. Glacio-eustasy is believed by many to be the primary mechanism responsible for the architecture of the Neogene stratigraphic record. Comparison of the stratigraphic records in the eastern Gulf of Mexico and in Jamaica indicates that the link to glacio-eustasy is not as straigthforward as suggested by some. In addition the evidence of downslope mass transport in the Gulf of Mexico points to a decisive tectonic role in the shaping of the sedimentary architecture of its Neogene record. The immediate consequence of this is that seismic surfaces and sequence boun aries may not carry, at least locally/regionally, the chronostratigraphic significance that has been ascribed to them.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California