Ocean Drilling Program; Leg 194 scientific prospectus; Marion Plateau

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Author(s): Isern, Alexandra R.; Anselmetti, Flavio S.; Baldauf, Jack; Blum, Peter
Author Affiliation(s): Primary:
National Research Council, Wahington, DC, United States
ERDW, Switzerland
Ocean Drilling Program, United States
Source: Scientific Prospectus, Vol.194, 86p. Publisher: Ocean Drilling Program, Texas A&M University, College Station, TX, United States. ISSN: 1058-1448
Note: In English. The reports in this series become obsolete after a cruise sails and will not be distributed. 39 refs.Scientific Prospectus No. 94
Summary: Cretaceous rifting in the western Coral Sea (offshore northeast Australia) formed continental fragments that are now capped by carbonate platforms. The Marion Plateau carbonate platform, which has grown on one of these fragments, provides a natural laboratory to study the causes, magnitudes, and effects of sea-level change on continental margin sediments. One of the fundamental controls on the nature and geometry of continental margin sediment deposition is sea level; however, much of the information on the relationship between sea-level and depositional facies is qualitative. Leg 194 coring will provide a superb and unique opportunity to determine the absolute magnitude of the major Cenozoic sea-level falls. The drilling strategy outlined for Leg 194 utilizes the stratigraphic relationship between a lower to middle Miocene second-order highstand carbonate platform complex and an upper Miocene second order lowstand platform complex to establish the magnitude of the middle Miocene N12-N14 sea level fall. An important characteristic of this platform relationship is that the proposed sites are essentially located along a single strike line without intervening structural elements. Thus, subsidence of the platform will have affected all sites equally, enabling determination of the true amplitude of the sea-level fall that caused a shift in the locus of carbonate platform deposition. The carbonate platforms and adjacent slopes of the Marion Plateau also preserve a superb record of third-order sea-level variations within a mixed carbonate-siliciclastic depositional environment. High-resolution seismic data collected for the Leg 194 site surveys provide quasi-three-dimensional images of Oligocene-Pliocene depositional geometries. The correlation of these seismic images with drill core and logging data will provide a synoptic view of depositional processes in a mixed carbonate-siliciclastic carbonate platform setting.
Year of Publication: 2000
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Bathymetry; Carbonate platforms; Cenozoic; Coral Sea; Cores; Cretaceous; Geophysical methods; Geophysical profiles; Geophysical surveys; Leg 194; Lithostratigraphy; Marion Plateau; Mesozoic; Ocean Drilling Program; Ocean floors; Pacific Ocean; Paleo-oceanography; Paleoenvironment; Reconstruction; Rift zones; Sea-level changes; Seismic methods; Seismic profiles; South Pacific; Southwest Pacific; Surveys; Tectonics; Tertiary; West Pacific
Coordinates: S210500 S201000 E1530500 E1514500
Record ID: 2007086564
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