Abstract: Sequence Stratigraphy and Diagenesis of the Lower Cretaceous Cupido Carbonate Platform Margin, Northeastern Mexico

The Lower Cretaceous (Barremian-Lower Aptian) Cupido Formation is part of a carbonate platform system that developed in the Sabinas Basin of northeastern Mexico. The Cupido carbonate platform is characterized by a reefal platform margin that is well exposed in northeastern Mexico. The Cupido carbonate platform and its subsurface stratigraphic equivalent in the Texas Gulf Coast (Sligo Formation) comprise an important hydrocarbon-producing interval. Regional stratigraphic relationships of the Cupido Formation are relatively well known but no detailed sequence stratigraphic studies have been conducted on the platform margin facies. Likewise, the diagenesis of the Cupido platform margin facies is poorly understood.

The main objectives of this project are to identify links between the stratigraphic evolution and diagenetic history of these facies. Measured stratigraphic sections will be correlated to photomosaics of laterally continuous, kilometer-scale outcrops of canyon walls in order to define facies architecture and stratigraphic relationships. Rock samples will be taken from all lithofacies of the platform margin and facies tracts that are immediately updip and downdip from the marginal facies belt. The sequence stratigraphy will provide the basic framework for diagenetic studies. Transmitted light and cathodoluminescence petrography, trace element and stable isotope geochemistry will be utilized in order to determine the diagenetic history of the Cupido Formation. Results from this study will provide a better understanding of porosity and permeability distribution in these carbonate strata. In addition, most studies of Cretaceous carbonate platforms have focused on middle to Upper Cretaceous platforms, whereas Lower Cretaceous platform stratigraphies are poorly documented. This is a critical time in Earth history when global climate purportedly was changing from "icehouse" to "greenhouse" conditions. Thus, this study may provide important stratigraphic models that will be useful for understanding Lower Cretaceous carbonate platforms around the world (including those in the Gulf Coast).

AAPG Search and Discovery Article #90940©1997 AAPG Foundation Grants-in-Aid