THE PALEOGENE BURGOS BASIN – INSIGHTS INTO PROVENANCE HISTORY, BASIN EVOLUTION, AND IMPLICATIONS FOR GULF OF MEXICO SEDIMENTATION

The Burgos basin straddles the NE Mexico-USA border region and during Paleogene time occupied the transition zone between the Laramide and Mexican orogens and the Gulf of Mexico (GOM). Considerable controversy surrounds the late Paleogene sediment routing system delivering sediment into the Burgos basin, including sediment dispersal and marine debouchment and the influence of the Tamaulipas arch and GOM faulting and salt movement. New LA-ICP-MS detrital zircon (DZ) U-Pb data from marine and nearshore fluvial-deltaic Paleogene strata from the Burgos basin in NE Mexico and S Texas to elucidate its provenance evolution, source-to-sink dynamics, and sediment accumulation/dispersal in the Burgos basin and Perdido area of the GOM. These data provide new provenance constraints exhibiting dominant Paleogene-Late Cretaceous age modes and subordinate Jurassic, 1.4, and 1.7 Ga and other age modes. Critically, these DZ data show a Cordilleran magmatic gap and lack Early Cretaceous Alisitos arc zircons, which is diagnostic for sources from the W USA. This also argues against sourcing from western Mexico and a connection to the Parras-La Popa basin routing system, which contains Alisitos-derived zircon. The Burgos basin dominantly received sediment via a paleo-Rio Grande system from a mixture of recycled sedimentary, volcanic, and basement source terranes in SE Arizona, N Mexico (Chihuahua trough, Sabinas uplift, and Coahuila block) and the Colorado Mineral Belt of SW Colorado. This continental-scale axial drainage system reached far back into the Cordilleran arc and was topographically channeled toward the GOM along the inversion flank of the Border Rift system and fed via transverse tributaries delivering recycled sediment from uplifting inverted early Mesozoic rift structures. The new DZ data unequivocally demonstrate that the Parras-La Popa drainage did not provide sediment to the Burgos basin and that the Tamaulipas-Burro arch acted as an effective routing barrier during the Paleogene, channeling sediment axially into the Burgos basin and blocking sediment transfer from W Mexico into the Burgos basin and the NW GOM. Importantly however, limited offshore Paleogene DZ data indicate that Peridido salt structures effectively sequestered sediment in the Burgos basin, separating it from deep-water GOM depocenters.