Regional depositional history of the Miocene-Pleistocene Louisiana Slope, Green Canyon and Mississippi Canyon
- Geco-Prakla, Houston, TX (United States)
A regional sequence-stratigraphic analysis was recently completed for the Tertiary slope sediments in Green Canyon, Ewing Bank, and Mississippi Canyon to provide a chronostratigraphic framework for basin reconstructions and predict lithofacies distributions of reservoir and seal rocks. Sixteen third-order sequences of lowstand deep-water deposits were interpreted for the middle Miocene-Pleistocene section. Thirty regional lithofacies maps were made of predominantly lowstand deposits showing the distribution of shale and sand-prone sediments, slumping, channel levee systems, and fan lobes based on distinctive seismic reflection and well log patterns. These maps were combined with isochrons of selected sequences to identify depositional fairways, depocenters, and paleosalt positions that constantly changed through time. Depositional trends were principally north to south but were also observed to be east-west as salt modified the gradient on the gently dipping slope. In some cases, the structural and stratigraphic trends could be projected under allochthonous tabular salt. Miocene channel and fan lobe sands were found concentrated on the middle-lower paleoslope across the study area. The sedimentation rate doubled (0.7 m/1000 yr) in the early-middle Pliocene, which caused large-scale salt movements and trapped sand-prone turbidites along the upper-middle slope. A four-fold decrease in sediment influx during the late Pliocene-early Pleistocene produced a stacked condensed section of four sequences over the eastern Louisiana slope. A return to rapid sedimentation (up to 2.1 m/1000 yr.) during the Pleistocene reactivated salt movements and depocenters in the Green Canyon, Ewing Bank, and Mississippi Trough areas.
- OSTI ID:
- 96257
- Report Number(s):
- CONF-941065--
- Journal Information:
- AAPG Bulletin, Journal Name: AAPG Bulletin Journal Issue: 9 Vol. 78; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Tectonostratigraphic reconstruction and lithofacies distribution of tertiary slope sedimentary rocks in the Western Mississippi Canyon area
Timing of turbidite sedimentation on the Mississippi Fan