CHICXULUB TARGET STRATIGRAPHY AND EJECTA COMPARED TO THE STRATIGRAPHY OF NORTHERN BELIZE

Laterally equivalent strata of the Cretaceous Yucatan Group, the target stratigraphic section of the end-Cretaceous Chicxulub impact event, occur in areas adjacent to Mexico, including northern Belize. In the absence of readily available subsurface data on lithologies within the Yucatan Group, it is a good strategy to use the relatively well known Cretaceous stratigraphic units, particularly the Yalbac and Barton Creek formations of northern Belize, as proxies for the analysis of provenance of carbonate clasts found within Chicxulub ejecta and crater-filling deposits. The Mesozoic stratigraphy of Belize includes formations that are the lateral equivalents of the target Yucatan Group (undivided) in Mexico and the Coban and Campur formations, respectively, of Guatemala. Belize stratigraphy of the northern (Corozal) basin includes four informal formations of interest, which lie above the trans-Yucatan crystalline basement complex. In age order, these are the Margaret Creek formation (red-bed clastics; equivalent of the Todos Santos in Guatemala and adjacent parts of Mexico), the Hill Bank formation (intercalated marginal marine clastics and shallow water carbonates and evaporites; equivalent of the Todos Santos transition zone in Guatemala and adjacent parts of Mexico), the Yalbac formation (shallow water dolostones and evaporites; equivalent of the Coban in Guatemala and the lower part of the Yucatan Group in Mexico), and the Barton Creek formation (shallow water dolostones; equivalent of Campur in Guatemala and the upper part of the Yucatan Group of Mexico). This paper examines these laterally equivalent target units in northern Belize and reviews how they pertain to a better understanding of the Chicxulub target.