Miospore diversity and its relationship to lithology in the Coker Formation (Upper Cretaceous) of western Alabama

A multiple-regression procedure was applied to samples from two cores of the Coker Formation (Upper Cretaceous) of western Alabama in an attempt to characterize the relationship between the diversity of miospore species and selected lithologic factors. The resulting prediction equations suggest that the number of miospore species in these samples is inversely related to changes in median grain size and to other as yet undefined factors not reflected by lithology. In addition, it appears that the degree of sorting of the sediment has no effect on species diversity. A plot of these prediction equations shows that changes in the number of miospore species are negligible in samples of clay and silt size but that the number of species decreases rapidly in sediments of fine sand size or coarser. The results presented here agree with those presented by other workers for the relationship between grain size and the absolute abundance of miospores.