Use of T-R
Sequence Methodology in the Analysis of the Onshore Interior Salt Basins of the
Gulf
of Mexico
Mancini, Ernest A.1 (1) University of Alabama, Tuscaloosa, AL
Stratigraphic analysis is critical in
the reconstruction of the geohistory of a sedimentary
basin. For the onshore interior salt basins of the northern Gulf of Mexico, where the stratigraphic section is characterized primarily by
non-marine and coastal sediments deposited in shelfal
areas and where stratal architecture is affected by
changes in sediment supply, climate and tectonics, in addition to sea level
changes, a T-R sequence approach is the preferred methodology for basin geohistory reconstruction. The T-R sequence method provides
a reasonable means for recognizing changes in stratigraphic
base level, which is the key factor affecting stratal
architecture in these non-marine and coastal deposits. T-R sequences, their
inherent systems tracts and subdivisions (transgressive
aggrading and backstepping and regressive infilling
and forestepping) and their bounding and defining
surfaces (subaerial unconformities, ravinement surfaces, transgressive
surfaces, surfaces of maximum transgression and surfaces of maximum regression)
provide an improved means for stratal correlation and
for the establishment of a chronostratigraphic
framework. These systems tracts and their subdivisions are recognizable by
characteristic well log signatures and seismic reflection configurations and
terminations. The bounding and defining surfaces have chronostratigaphic
significance and provide time lines for the analysis of the depositional,
tectonic, burial and thermal maturation histories of a given basin. The T-R
sequence concept has application in designing enhanced exploration strategies
in the recognition of specific continental and coastal facies
that have reservoir potential and in the identification and delineation of
potential stratigraphic traps.