Preliminary analysis of mineralogical trends through time in two large clastic wedges in the northwestern Gulf of New Mexico Basin (Wilcox and lower Claiborne Groups), and time-equivalent upper Paleocene-lower Eocene strata in Laramide basins of the Southern Rocky Mountains, suggests that the two-phase uplift history of Laramide orogeny described by Chapin and Cather (1983) may be recorded by detrital mineralogy. Temporal changes in composition also indicate that changing climate played a role in the evolution detrital mineralogy. The proposal is to study the temporal changes of detrital and diagenetic mineralogy in the Wilcox and lower Claiborne Groups of the northwestern Gulf of Mexico Basin, and coeval sediments in Laramide basins of the Southern Rocky Mountains. This information will provide a test of the theory that pulses of intracontinental Laramide tectonism are recorded by episodes of deltaic-wedge progradation in the Gulf of Mexico Basin. In particular, we will address the question: Is the response of delta growth geologically instantaneous, or does a geologically significant lag-time exist between filling of basins adjacent to interior uplifts and the deposition of associated sediment at the continental margin? Palynological analysis of sample intervals will place the trend of mineralogical changes within a time framework. This temporally constrained analysis of mineralogical changes will allow an assessment of synchroneity between interior-continental orogeny and continental-margin sedimentation.
