GULF INTRASLOPE BASINS PROJECT (GIB)

SEA-LEVEL CONTROL OF LATE QUATERNARY DEPOSITIONAL FACIES AND PROCESSES IN NORTHERN GULF OF MEXICO INTRASLOPE BASINS

AN INDUSTRY SPONSORED CONSORTIUM

Principal Investigators:

Hilary C. Olson (University of Texas at Austin, Institute for Geophysics) and

John E. Damuth (University of Texas at Arlington, Earth Resource and Environment Center)

Project Summary

     
Figure 1. Study are of the GIB Project.            Figure 2. Data coverage of 3.5 kHz seismic.

Figure 3. Seismic-facies map constructed from over 71,000 km of 3.5 kHz data in the Gulf of Mexico Intraslope Basin area as part of this project show on left.  Each color represents a different echo-character observed on the 3.5 kHz data.  For a detailed summary of echo-character facies classification, see Damuth, J.E., 1980, Use of high-frequency (3.5-12 kHz) echograms in the study of near-bottom sedimentation processes in the deep sea:  A review, Marine Geology, v. 38, p. 51-75. GLORIA mosaic of the Mississippi Fan area is shown to right.

The northern Gulf of Mexico is one of the best studied hydrocarbon provinces in the world. Despite voluminous studies of the Cenozoic sedimentation and tectonic history and the enormous industrial interest, relatively few studies have focused on the latest Quaternary depositional processes and faunas of the intraslope basins even though these "modern" analogs can potentially provide excellent models for predicting sediment facies and sand-body geometries of more deeply buried productive deposits. A wide variety of very high-resolution data sets (seismics, side-scan sonar, bathymetric swath maps, shallow cores) now exist for intraslope basins and can be utilized to effectively examine the details of Late Quaternary intraslope basin deposits. Integrated analyses of these data sets reveal the details of the depositional features present (e.g. submarine fans; mass-transport deposits; contourite deposits), their architecture (e.g. channels, overbank deposits, lobes, slumps, debris flows, sediment drifts), their depositional processes (turbidity currents, bottom currents, plastic flows, etc.) and, ultimately, their sediment facies distributions (sand vs. shale). In addition, biostratigraphic zonation and biofacies analysis of these deposits permit correlation of sedimentation processes and facies with high-order (4th-6th order cycles) climatic and sea-level cycles. Such correlations have been used to compare depositional features, processes and facies, as well as faunal patterns, with existing sequence-stratigraphic and sea-level models to "ground-truth" existing models and to calibrate them so that they can be more effectively utilized to predict the depositional settings and facies of more deeply buried, prospective intraslope basin deposits. Since 1998 we have conducted a detailed, comprehensive and integrated synthesis of the late Quaternary depositional processes and facies in intraslope basins and documented the influence of sea-level changes on controlling these facies and processes. The research integrates seismic interpretation, sedimentology and biostratigraphy from previously collected seismic data and piston cores. 

The following companies supported Phase I of GIB (1998-2000):

AGIP, Amoco, Anadarko, BP, Conoco, Elf, Marathon, Spirit Energy, Texaco and Vastar.

We are currently soliciting funds for a Phase II of GIB (2001-2004) which will also involve Drs. Hans Nelson and Bill Bryant at Texas A&M University.

In addition, the U.S. Geological Survey supported a cooperative study on their data from the same study area in the Gulf of Mexico. These data have been included in the Phase I results.

For more information on the Gulf Intraslope Basins Project (GIB) at the Institute for Geophysics please contact Hilary Olson or Patty Ganey-Curry, or at the University of Texas at Arlington contact Jed Damuth.

Proposed Objectives (numerals),

Results (bullets) and

Deliverable Dates (parentheses) of GIB Phase I (1998-200)

1.        Examine and describe 175 piston cores in GOM intraslope basins to interpret the various sandy and muddy sediment facies of intraslope basins in terms of the depositional processes (e.g. turbidity currents, mass-transport etc.). 

·         239 cores examined from 18 cruises (plus additional LDEO cores logged)

·         Descriptions and photographs in GIB Project Atlas

(October, 2000)

2.        Correlate the sediment facies of piston-cores with 3.5 kHz seismic facies (echo character) of the uppermost sea floor to identify the depositional features (e.g. fans, channels, levees, lobes, slumps etc.) that were cored and to determine their geometries and confirm depositional processes observed in the cores.

·         239 cores examined from 18 cruises (plus additional LDEO cores logged)

·         Descriptions and photographs in GIB Project Atlas

·         Seismic profile photographs in GIB Project Atlas with core locations

(October, 2000)

3.        Construct a regional 3.5 kHz seismic facies (echo character) map of the entire GOM intraslope basin province to define regional distributions of depositional features, processes, and environments including submarine fans, channels, levees, lobes, mass-transport deposits and bottom-current deposits.

·         ~71,000 km of seismic data interpreted

·         Map included as part of GIB Project Atlas

(August, 1999; update October, 2000)

4.        Determine latest Quaternary stratigraphy of the piston cores using foraminiferal biostratigraphy and chemical stratigraphy (e.g. carbonate content) to determine ages, climatic zones and sea-level fluctuations. Compare the relationship of terrigeneous sediment deposition and facies with glacio-eustatic sea-level cycles and evaluate existing sequence-stratigraphic models in terms of deep-water facies prediction. Assess the effect of sea-level control of terrigeneous sediment from basin to basin to see how basins progressively fill throughout the region. 

·         97 cores analyzed for stratigraphy

·         Digital and printed data in Core Data Report

·         Graphs included in GIB Project Atlas with discussion of correlation

(October, 2000)

5.        Define the benthic foraminiferal signature of various seismic facies (echo character) and sedimentary processes to characterize the faunal nature of specific depositional facies, then create a predictive model based on these foraminiferal faunas (post-doc: Graham Moss).

·         335 samples from 26 cores in 15 minibasins analyzed for biofacies analysis

·         Digital and printed data in Foraminiferal Data Report

·         Discussion and figures illustrating biofacies and depositional facies correlation in GIB Project Atlas

(October, 2000)

6.        Compile project and report within a GIS framework using ARCVIEW software.

·         All maps, seismic profiles, shiptracks and cores compiled into several ARCVIEW Projects

·         Hyperlinks established from ARCVIEW to seismic, core and paleo images/photos in html format

(December, 2000)