Phase 1 Background  The Gulf of Mexico Intraslope Basins Project (GIB) is an industry-supported study initiated in 1998 to conduct a detailed, comprehensive and integrated synthesis of latest Quaternary depositional processes and facies in intraslope basins, and to document the influence of sea-level changes on controlling these facies and processes.  The research integrates 70,000 km of seismic, sedimentology from ~ 300 piston cores and biostratigraphy from the most stratigraphically coherent cores. A regional 3.5 kHz seismic facies map was produced in characterizing sandy facies and depositional processes and features in the intraslope basin region.  The distribution of a GIS database integrating all seismic, sedimentologic and biostratigraphic results, and a core workshop held at the Ocean Drilling program in College Station, TX completed Phase 1 of the project in October, 2000. (See attached deliverables sheet for GIB 1 for further details.)

Phase 2 Proposed  A second 3-year phase of the project will start in early 2001.  This phase will augment Phase 1 by further calibrating our seismic facies map, and enhancing our understanding of modern seafloor and latest Quaternary processes.  In addition, data collected and analyzed will reduce the risk involved in selecting the best and safest locations for the placement of seabed structures related to the exploitation of hydrocarbons, including templates, piles and pipelines. We propose a cruise in one or two selected areas (based on results of GIB 1) to study sediment transport/sourcing, sand-body geometries, sediment stability, and timing of sediment mobility. Funds will be used to:  (1) collect and analyze new Deep Tow seismic and core data, and (2) to analyze existing Deep Tow seismic and core data at Texas A&M University (TAMU).

The TAMU Deep Tow system enables collection of 3.5 or 7 kHz subbottom data, as well as 100 kHz side-scan data.  The positively buoyant "Fish" is towed at a constant height (30m) above the seafloor, resulting in subbottom profiles and side-scan sonographs with outstanding clarity, resolution and consistency in any waterdepth (Fig. 4).  Deep Tow data currently exist for the Alaminos Canyon and Bryant Canyon systems; and we propose to collect additional data from the East Breaks slide/channel system, Rudder-Magellan sandy turbidite system and/or Rio Grande sandy channel system (at the discretion of the consortium members).  Previously collected cores (a subset of Western Gulf SGE Program cores donated by TDI-Brooks International to Texas A&M) will be analyzed and new cores will be collected as needed to calibrate seismic data and compose a more complete database.

Scientific Objectives

1.  Examine current Deep Tow data previously collected (Alaminos and Bryant Canyons); integrate Deep Tow data with core data to further calibrate facies map from GIB Phase 1.

2.   Examine subset of 300 cores at TAMU; describe depositional processes, characterize lithology, establish biostratigraphic framework and integrate these analyses with ~ 300 previously described cores (GIB Phase 1), previously constructed seismic facies map (GIB Phase 1) and all Deep Tow data.

3.  Conduct Deep Tow cruise in areas of interest; collect data in Rudder-Magellan sandy turbidite system, Rio Grande sandy channel system and/or East Breaks slide and channel system.

4.  Collect additional piston cores in specific areas mentioned in #3 above; further calibrate seismic facies map (GIB Phase 1) and understand depositional processes, sediment geometries and seafloor lithology.

Planned Deliverables

1.  Series of seismic maps characterizing the sea floor and latest Quaternary depositional processes in the areas of Deep Tow data (Year 1/2: collection of data on cruise; Year 2: GIS maps).

2.  Report describing lithology and depositional processes of modern seafloor and latest Quaternary sediments; core descriptions and photographs (Year 3: GIS database and report).

3.  Updated seismic facies maps of intraslope basin region including enhanced calibration with new core information and Deep Tow seismic data (Year 3: GIS map).

Cost: $25,000/year for 3 years (total=$75,000)