Integrated Ocean Drilling Program, Expedition 308 scientific prospectus; Gulf of Mexico hydrogeology; overpressure and fluid flow processes in the deepwater Gulf of Mexico; slope stability, seeps, and shallow-water flow

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doi: 10.2204/iodp.sp.308.2005
Author(s): Flemings, Peter B.; Behrmann, Jan H.; John, Cédric
Author Affiliation(s): Primary:
Pennsylvania State University, Department of Geosciences, University Park, PA, United States
Albert-Ludwigs-Universität Freiburg, Federal Republic of Germany
University of California, Santa Cruz, United States
Source: Scientific Prospectus (Integrated Ocean Drilling Program), Vol.308, 52p. Publisher: IODP Management International, College Station, TX, United States. ISSN: 1932-9415
Note: In English. Includes appendices. 30 refs.
Summary: Integrated Ocean Drilling Program Expedition 308 is an abbreviated form of Proposal 589-Full 3 entitled "Overpressure and Fluid Flow Processes in the Deepwater Gulf of Mexico: Slope Stability, Seeps, and Shallow Water Flow". We will explore the coupling of overpressure, flow, and deformation in passive margin settings. We will test a multidimensional flow model by examining how physical properties, pressure, temperature, and pore fluid composition vary within low-permeability mudstones that overlie a permeable and overpressured aquifer. Drilling, logging, and in situ measurements will be performed in the Brazos-Trinity #4 minibasin and in the Ursa region of the northern Gulf of Mexico. These basins are 300 km apart and have experienced very different Pleistocene sedimentation histories. Brazos-Trinity #4 will serve as a reference location because its low sedimentation rate generated little overpressure. In contrast, Ursa experienced extreme sedimentation rates, has high overpressures, and will serve as a type location to study overpressure and flow. Drilling and consequent postcruise studies will illuminate controls on slope stability, seafloor seeps, and large-scale crustal fluid flow. Two key components of the experimental plan are to take substantial whole-core geotechnical samples for later shore-based analysis and to deploy a tapered penetrometer, the T2P probe (developed jointly between the Massachusetts Institute of Technology [MIT; USA], the Pennsylvania State University [USA], and IODP) to measure in situ pressure and temperature. Expedition 308 science will meet many of the objectives proposed in the original IODP Proposal 589-Full3 and will provide the foundation to implement long-term in situ monitoring experiments in the aquifer and bounding mudstones in a future expedition to meet the full objectives of IODP Proposal 589-Full3.
Year of Publication: 2005
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 20 Geophysics, Applied; 21 Hydrogeology and Hydrology; 24 Surficial Geology, Quaternary Geology; Aquifers; Atlantic Ocean; Boreholes; Brazos-Trinity Basin; Cenozoic; Circulation; Continental margin; Continental slope; Cores; Data acquisition; Data processing; Downhole methods; Drilling; Expedition 308; Expeditions; Flows; Fluid phase; Geophysical methods; Geophysical profiles; Geophysical surveys; Ground water; Gulf of Mexico; Hydrodynamics; Integrated Ocean Drilling Program; Louisiana; Marine drilling; Marine sediments; Mars-Ursa Basin; Mass movements; North Atlantic; Northern Gulf of Mexico; Overpressure; Planning; Pore pressure; Quaternary; Sampling; Sediments; Seismic methods; Seismic profiles; Seismic stratigraphy; Slope stability; Slumping; Surveys; Texas; United States; Well-logging
Coordinates: N271500 N280600 W0890000 W0942500
Record ID: 2007088834
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