Seismic stratigraphy and salt tectonics of the northern Green Canyon area, Gulf of Mexico /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1987.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Analysis of over 4800 km of multichannel and single channel seismic data over the northern Green Canyon area reveals a complex region of thick sedimentary sequences underlain by extensive salt structures. At least seven major seismic sequences comprise the Pleistocene on the upper slope. Two major salt provinces were mapped, based on gross morphology. The northern province consists of shallow, isolated stocks and low relief salt anticlines or swells while the southern province consists of steep sided salt ridges and massifs which trend NE-SW. Within these provinces are sixteen distinct intraslope sedimentary basins. Faulting, salt withdrawal, and salt growth are the major factors governing basin development. Trends of basins of similar origin are found parallel to the shelf edge. Mature, fault related basins are closest to the shelf edge. Salt withdrawal basins are found farther downslope, followed by younger salt influenced basins farthest offshore. This suggests that salt deformation is related to distance from the shelf edge. Analysis of salt growth around the basins reveals intermittant salt movement in response to sediment loading updip. Bathymetric lows over some diapirs develop from faulting over the dome, erosion of the sediment and underlying salt followed by rapid sediment infilling. Five seismic facies were identified. Turbidity currents, mass movement, pelagic and hemi-pelagic sedimentation are the major sedimentary processes interpreted from the data. Eastward migration of channels and fan lobes and a southeastward shift of the prograding shelf edge with time are shown from the distribution of seismic facies. An ideal seismic sequence, based on seismic data and available well data consists of reflections related to three stages of sea level. During lowering of relative sea level, progradation of the shelf edge occurs. Low energy turbidity current deposits and mass movement deposits fill pre-existing lows. Channels and fan lobes are found in areas of low relief. During lowstand and initial rapid rise, high density turbidity current deposits are widespread. Channels are infilled as movement decreases downdip. Slumping and sliding occurs on the flanks of upward moving diapirs. At a slower rise and stillstand, the major sedimentary processes are mass movement at the shelf edge and pelagic and hemipelagic sedimentation. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Oceanography." |
| Physical Description: | xvi, 219 leaves : illustrations (some folded), maps ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 211-218). |