147 Structural Geology / Tectonics / Neotectonics/Paleoseismology (Posters)
Margin Tectonics of Northern Gulf of Mexico Coastal Plain, Shelf, and Slope Proposed to Impact Basement and Mantle
Paper number: 147-24
Program: Technical Sessions
Time: 8:00 AM – 4:45 PM
Authors
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Linda JenkinsPicayune, MS
Abstract
Principal constant force input is gravity. Downslope motion causes earthquakes (brittle fracture) and slow/silent earthquakes (plastic deformation). Earthquakes generate “instantaneous” energy that accelerates ongoing geologic processes. Slow/silent earthquakes move sediment volumes, reorienting mass location and further movements/dynamics. Instantaneous pressure waves from meteor impacts and great earthquakes act as margin-wide energy inputs. Catastrophic glacial lake collapse deposition creates events that last less than a year and deposition rate changes of 3 to 4-5 orders of magnitude. These low-frequency, pressure-generating events create pressure waves. Margin evolutionary processes generate energies that drive tectonic growth.
Within margin progradation, there is aggradation and progradation with sea-level oscillation. The maximum deposition loci oscillates across the margin, changing compression onto the basement. Following isostacy basement depression, given the changing sedimentary cover, thicknesses could vary 60-90% of sediment cover. With successive sediment accumulation, the basement continues to be depressed. These basement-depth-related changes vary basement impact onto overlying sediments with heat, geothermal and geochemical fluids.