Sequence Stratigraphic Model of the Rio Grande Delta, South West Texas: Potential Analog for the Niger Delta
Laura A. Banfield, John B. Anderson, and Peter R. Vai
A sequence stratigraphic model developed from the ancient Rio Grande Delta in South West Texas is suggested as an analog for the Niger Delta.
The two delta systems are characterized by high sand bedloads, shale diapirism with associated listric normal faulting, and large amounts of tidal and wave influence forming lower coastal plains characterized by swamps and estuaries. The sequence stratigraphic model of the ancient Rio Grande delta is based on approximately 1200 kilometers of single channel, 15 cubic inch water gun data, lithologic descriptions from approximately 25 long cores (28-30 m) located in 17-94 meters water depth, three gamma ray logs, paleontologic data from two cores, and oxygen isotopic data from one core (152 meters in length and located in 94 meters water depth). The combined data indicate that considerable quantities of sand are sequestered on the continental shelf and point sourcing the slope. The Rio G ande sequence stratigraphic model provides an improved understanding of sand deposits on the shelf, of the role of sediment bypass during lowstands, and of the base of slope deposits formed by headward eroding canyons (?) or channels (?) located at the shelf break. This information regarding the distribution of sand in the Rio Grande system can provide valuable insight into the reservoir distribution in the Niger system, improving existing reservoir predictions.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California