DEPOSITIONAL ENVIRONMENTS AND PROVENANCE OF THE MAASTRICHTIAN CAÑON DEL TULE FORMATION, PARRAS BASIN, NORTHEASTERN MEXICO

The Cañón del Tule Formation is the third formation, from the bottom, of the Difunta Group, which is a several kilometers thick succession deposited in the Parras Basin. The Parras Basin is defined as a syntectonic foreland basin, associated with the arcuate section of the fold and thrust belt, in east-central Mexico. In this study, a detailed column of the Cañón del Tule Formation was measured, recording sedimentary structures and textures; sandstone samples were obtained for point counting analysis. With the field information, 6 facies were identified that are interpreted as deposited on pro-delta, delta plain (distributary channels) and delta front. These depositional environments record a full sea-level change cycle, beginning at the bottom of the formation with delta plain, changing up section to delta front, and to pro-delta at the middle of the column. Then it changes up section again to delta front and delta plain at the top of the formation. Sandstone of the Cañón del Tule Formation is mostly fine to medium-grained with a few coarse-grained sandstones. It is composed mostly of quartz and feldspar clasts, with a few rock fragments that are mostly volcanic (felsic and andesitic), but a few chert, limestone and sandstone grains were found. Point counting results were plotted in Dickinson (1986) ternary diagrams. They fall mostly in the recycled orogen field and a few in the dissected arc field. This indicates a volcanic/granitic main source, but sedimentary rocks were also eroded. We propose that the possible source areas for the sandstone of the Cañón del Tule Formation might be located toward the west of the Parras Basin, mainly in Sonora and Sinaloa states. This is based on the fact that Upper Cretaceous volcanic rocks (Tarahumara Formation) that rest on granitoids, and several formations of sedimentary rocks of Paleozoic and Mesozoic age, are found in that region of western Mexico.