The Texas mud blanket: Understanding fine-grained sediment flux in the NW Gulf of Mexico during the previous transgression.

摘要

The evolution and source of the Texas Mud Blanket (300 km3) was determined from 26 new radiocarbon dates and from &sim3000 km of 2D seismic data. Sediment flux (km3/ka) was calculated from this combined dataset. XRD reveals its origins are mostly from the Colorado and Brazos Rivers.Between LGM and 17 ka, sediments filled the deepest accommodation behind a productive reef trend. 17-9 ka was a time of rapid eustatic rise (&sim7 mm/year) and low sedimentation (flux=0.4 km3/ka). At &sim9 ka, sediment flux to the mud blanket increased to 41 km3/ka because of ravinement of Brazos and Colorado deltas. By &sim5.5 ka, Texas was experiencing a climatic optimum, which reduced sediment supply from local rivers. During the last 3.5 ka the mud blanket received 172 km3 of fine-grained Colorado and Brazos sediments. The most pronounced trend is the anti-correlation of mud blanket growth and rates of eustatic rise.