--> Abstract: Stratal Slicing Imagery Of A Fluvial-Deltaic-Microtidal Shore-Zone System In Plio-Pleistocene, Onshore Louisiana, by H. Zeng; #90928 (1999).

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ZENG, HONGLIU
Bureau of Economic Geology, The University of Texas at Austin, Austin, TX

Abstract: Stratal Slicing Imagery of a Fluvial-Deltaic-Microtidal Shore-Zone System in Plio-Pleistocene, Onshore Louisiana

A 3-D seismic volume of 14 x 14 km in south Louisiana records an interval of Plio-Pleistocene sediments in a 0.5- to 1.8-s section. Discrete, incomplete channels can be interpreted on time slices and horizon slices (parallel to a single reference event). Before the stratal slicing technique was applied to the data set, a detailed analysis of depositional history could not be attempted because of limited well information and the difficulties in slicing wedged seismic sequences. By slicing proportionally between successive chronostratigraphic seismic events (flooding surfaces), 300 stratal slices were made sequentially to image seismic amplitude patterns on interpreted depositional surfaces. Similar to depositional images on satellite pictures, seven main depostional facies have been identified (in the order of frequency of occurrence): (1) numerous meander channels (0.03 to 2 km wide) in coastal streamplains, (2) lagoon, (3) barrier bar/shoreface, (4) bay-head deltas that were located in the lagoon and connected updip to meander feeder channels, (5) cuspate or wave-dominated deltas, (6) bird-foot or fluvial-dominated deltas and (7) giant meander channels (as much as 5 km wide) with details of point bars and crevasse splays depicted. Showing those stratal slices in the order of relative geologic time (movie format) gives interpreters a sense of depositional history. Facies shifts between stratal slices record at least 10 cycles of relative sea-level change (fourth order or finer).

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas