Late Quaternary Evolution of the Rio Grande Delta: Complex Response to Eustasy and Climate Change
Laura A. Banfield, John B. Anderson, 2004. "Late Quaternary Evolution of the Rio Grande Delta: Complex Response to Eustasy and Climate Change", Late Quaternary Stratigraphic Evolution of the Northern Gulf of Mexico Margin, John B. Anderson, Richard H. Fillon
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The Rio Grande Delta stood as a prominent feature on the south Texas shelf for virtually the entire last glacioeustatic cycle. During its evolution, the delta alternated between fluvial-dominated and wave-dominated regimes. Changes in delta geomorphology and facies resulted from variations in sediment supply and sea-level change. The highstand delta was initially wave-dominated but shifted to fluvial-dominated as sea level continued to fall. A large shelf-margin delta and slope fan formed during the lowstand. The delta backstepped onto the shelf during the transgression and was a fluvial-dominated system for a period of time in the mid-transgression. This phase of delta growth was undoubtedly caused by an increase in sediment supply. By mid-Holocene time, rising sea level and reduced sediment supply resulted in the delta backstepping to its current location. Holocene sedimentation has buried offshore parts of the delta beneath a hemipelagic mud blanket.
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The northern Gulf of Mexico margin encompasses a variety of depositional settings characterized by different drainage basin size, physiography, fluvial morphology, climatic setting, and structural and diapiric activity. This, plus the abundance of long sediment cores and platform borings from oil industry activities, make it an unparalleled natural laboratory for sedimentological and stratigraphic studies and for testing sequence stratigraphic concepts. This volume contains twelve papers describing results from high-resolution stratigraphic studies of late Quaternary strata of the northern Gulf of Mexico, from the mouth of the Apalachicola River to the Rio Grande. These papers focus on fluvial response to climate and base-level change, variations in delta growth and evolution across the shelf, lowstand delta-fan evolution, the evolution of transgressive deposits on the shelf, the preservation of these deposits. The robust chronostratigraphic frameworks developed for the different study areas allows comparison of stratal geometries produced by contemporaneous depositional systems operating under identical eustatic conditions. This volume will appeal to sedimentologists and stratigraphers interested in source to sink issues, such as how various forcing mechanisms influence strata formation on continental margins.