Late Cretaceous and Paleogene Sediment-‐dispersal Systems in an Evolving Foreland-‐basin System, Northern and Central Mexico Lawton, Timothy F. Centro de Geociencias Universidad Nacional Autónoma de México (UNAM) Blvd. Juriquilla No. 3001 Querétaro, 76230, México
[email protected] Juárez-‐Arriaga, Edgar Centro de Geociencias Universidad Nacional Autónoma de México (UNAM) Blvd. Juriquilla No. 3001 Querétaro, 76230, México
[email protected] Ocampo-‐Díaz, Yam Zul Ernesto Área de Ciencias de la Tierra Facultad de Ingeniería Universidad Autónoma de San Luís de Potosí Av. Dr. Manuel Nava No. 8 San Luis Potosí, 78290, México
[email protected] Beltrán-‐Triviño, Alejandro Geological Institute ETH Zurich, Switzerland
[email protected] Martens, Uwe Tectonic Analysis Inc. 1315 Alma Ave, Ste 134 Walnut Creek, CA 94596, USA
[email protected] Stockli, Daniel Department of Geological Sciences Jackson School of Geosciences The University of Texas at Austin, TX 78712-‐0254, USA
[email protected] The Mexican Interior Basin of northern and central Mexico formed in early Late Cretaceous time as a narrow retroarc foreland basin. During the Late Cretaceous and Paleogene, the basin migrated eastward, ahead of an advancing thrust belt. All sandstones in the basin have a dominant or important volcanic-‐lithic component, indicating sediment sources in a coeval
continental-‐margin magmatic arc along Mexico’s western margin. Nevertheless, temporal differences in detrital-‐zircon content demonstrate that distant basement and sedimentary rocks of southwestern Laurentia constituted important sediment sources during early (Cenomanian-‐ Turonian) and late (Campanian-‐Maastrichtian and Paleogene) stages in basin evolution; during an intermediate stage (Coniacian-‐earliest Campanian), the Laurentian sources were evidently absent and most pre-‐Late Cretaceous grains were derived from accreted rocks, which formed the arc basement in western Mexico. Sediment-‐dispersal systems evolved in concert with the stages of basin development. During the Cenomanian-‐Turonian stage, turbidites deposited in central Mexico had headwaters as far away as northwesternmost Mexico. The initial basin possessed a narrow foredeep filled by sediment-‐gravity flow deposits with dominantly axial sediment transport. Carbonate platforms of eastern Mexico supplied calclithites to the foredeep and indicate important influence of pre-‐ foreland paleotopography on early sediment fill. In contrast, headwaters for Coniacian-‐ Campanian deep-‐water deposits probably lay nearer to the depositional site, in western Mexico. Late-‐stage uppermost Cretaceous-‐lower Eocene shallow marine and continental strata of the Parras and La Popa foreland depocenters of northeastern Mexico were linked to a fluvial drainage basin whose extent was probably the greatest in Mexico, reaching northwestward to the United States. Time-‐equivalent Paleogene turbidite deposits of the Tampico-‐Misantla basin in eastern Mexico were derived from local sources in the thrust belt and the adjoining magmatic arc of central Mexico. Paleogene sediment-‐transfer systems across northern Mexico were therefore complex and suggest that deepwater sediment accumulations in the western Gulf of Mexico can be expected to have sharply contrasting compositional characteristics controlled by the extent and compositional characteristics of the upstream drainage basins.
