Models for fine-scale movements along growth faults associated with climate/sea level changes
Along the northern Gulf of Mexico, the deglaciation phase of a Pliocene-Pleistocene glacial cycle produced up to a tenfold increase in waters available for sediment transportation to continental margins. With lowered sea levels during glacial maxima, sedimentary pulses are deposited along the shelf break and on the slope. High-energy deposition promotes foundation instability. Growth faults then originate along the shelf break. Increased lithostatic pressure due to rapid deposition on underlying unconsolidated and semiconsolidated sediments, semiplastic salt, and marine clays promote flow that accelerates compaction, fluid migration, growth fault movements, and salt tectonics. Sedimentary depositional cycles of deca- and centenary-millennia are recorded throughout the Phanerozoic. Planetary orbital motions, controlling the amount of incoming solar radiation and lasting 20,000, 40,00, and 100,000 years, apparently cause these depositional cycles via climate/sea level fluctuations. When sea level is low, sediments are deposited about or beyond the shelf break. Increased lithostatic pressure promotes movement on the fault, deposition on the downthrown block, accelerated compaction of sediments, and fluid expulsion and migration. When sea level is high, sediment deposition is along the upper and middle shelf. Fault activity should be minimal or nil. Thus, the geologic episodes that record the greatest amount of downthrown block growth may also be punctuated by bursts of large drops in sea level. Onshore Louisiana production is usually greatest from maximum growth downthrown blocks.
- Research Organization:
- Resource Finders, Inc., Picayune, MS
- OSTI ID:
- 7152601
- Report Number(s):
- CONF-8610199-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:9; Conference: 36. annual meeting of the Gulf Coast Association Geological Societies and the Gulf Coast Section of SEPM, Baton Rouge, LA, USA, 22 Oct 1986
- Country of Publication:
- United States
- Language:
- English
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