Mancini, Ernest A.1, T. Markham Puckett1
(1) University of Alabama, Tuscaloosa, AL
ABSTRACT: Sequence Stratigraphic Analysis of Continental and Shelfal Strata, Northern Gulf of Mexico
Sequence stratigraphy provides a means for correlation of strata through the recognition of sequences that are bounded by unconformities or correlative conformities. Although stratal architecture on passive continental margins is affected by changes in sea level, climate, tectonics and sediment supply, the stable nature of passive margins has led to the assumption that global sea level changes are the primary factors controlling stratal patterns. Therefore, current stratigraphic analysis of marine and nonmarine strata is based chiefly on depositional sequences that are controlled by eustasy. However, a sequence stratigraphic approach based solely on eustasy has little application where applied to nonmarine strata. The architecture of these strata is controlled by changes in stratigraphic base level, which in continental deposits functions independently from changes in eustasy. Factors affecting stratal patterns in these deposits include tectonics, sediment supply, and climate. A need exists for a sequence stratigraphic approach that incorporates these factors in addition to sea level and has application for correlating and mapping lithofacies associations in continental to shelfal depositional systems. The concept of transgressive-regressive (T-R) cycles fulfills this need. T-R cycles have excellent utility for establishing a stratigraphic framework for stratal correlation in the northern Gulf of Mexico area. These cycles are recognized by a combination of factors including stratal geometries, nature of cycle boundaries, facies stacking patterns within cycles, and large-scale shifts in major facies belts.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.