Skip to Main Content
Book Chapter

Late Quaternary Deposition and Paleobathymetry at the Shelf–Slope Transition, Ancestral Mobile River Delta Complex, Northeastern Gulf of Mexico

By
Richard H. Fillon
Richard H. Fillon
Earth Studies Associates, 3730 Rue Nichole, New Orleans, Louisiana 70131-5462, U.S.A.
Search for other works by this author on:
Barry Kohl
Barry Kohl
Department of Geology, Tulane University, New Orleans, Louisiana 70118-5698, U.S.A.
Search for other works by this author on:
Harry H. Roberts
Harry H. Roberts
Coastal Studies Institute and the Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, U.S.A.
Search for other works by this author on:
Published:
January 01, 2004

Abstract

During lower-sea-level parts of glacioeustatic cycles, limited accommodation on the northeastern Gulf of Mexico shelf creates a stratigraphic framework within which the thickest deltaic and open marine section is confined to a narrow zone at the shelf edge. Key to understanding ancestral Mobile River delta complexes including the Lagniappe and older deltas is establishment of a 14C and oxygen isotope stratigraphic framework. The δ18O record in a corehole penetrating deltaic and prodeltaic section on the upper slope, in Viosca Knoll block 774, contains normal glacial and interglacial values related to isotope stages 1–13 as well as evidence of meltwater spikes at the stages 1–2 and stages 13–14 glacial terminations. A second 14C calibrated deltaic–prodeltaic δ18O record in an outer-shelf corehole located in Main Pass Block 303 contains normal glacial and interglacial values and a stages 1–2 meltwater spike in the upper part, but in the lower part contains evidence of diagenetic precipitation of isotopically light CaCO3 related to pore-water and methane seepage. This added carbonate creates an anomalously light δ18O and δ13C overprint in the data but does not appear to negate the utility of the δ18O signal in resolving isotope stages 5–8.

With the detailed chronology made possible by fine-tuning the δ18O stratigraphy it is possible to track the changes in relative sea level that are important to the development of deltaic morphology and stacking patterns and to the proliferation of benthic foraminiferal assemblages. We have been able to demonstrate that during deposition of the Lagniappe and related deltaic systems, relative sea level is controlled by glacio-eustatic sea-level variations, compaction-induced seafloor subsidence, and seafloor movements related to isostatic loading. Investigation of the complex relationships between these factors and the stratigraphic record over several glacial terminations is supported by graphical stratal-history analysis of corehole data. Temporal backtracking of deltaic–prodeltaic strata in the interval 0–500 ka reveals a northeastern Gulf of Mexico continental margin that is progradational at the scale of glacioeustatic sea-level change and individual lowstand deltas, such as the Lagniappe Delta, and retrogradational at the scale of shelf-margin evolution, sequence stratigraphy, and exploration geophysics.

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables

Contents

SEPM Special Publication

Late Quaternary Stratigraphic Evolution of the Northern Gulf of Mexico Margin

John B. Anderson
John B. Anderson
Search for other works by this author on:
Richard H. Fillon
Richard H. Fillon
Search for other works by this author on:
SEPM Society for Sedimentary Geology
Volume
79
ISBN electronic:
9781565762152
Publication date:
January 01, 2004

GeoRef

References

Related

A comprehensive resource of eBooks for researchers in the Earth Sciences

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal