Skip to Main Content
Book Chapter

Ichnology of the Bridge Creek Limestone: Evidence for Temporal and Spatial Variations in Paleo-Oxygenation in the Western Interior Seaway

By
Charles E. Savrda
Charles E. Savrda
Department of Geology, Auburn University, Auburn, AL 36849-5305
Search for other works by this author on:
Published:
January 01, 1998

Abstract

The Upper Cretaceous (Cenomanian-Turonian) Bridge Creek Limestone is characterized by decimeter-scale alternation of pelagic limestones and marly shales that were deposited under variably oxygenated waters. Vertical stacking patterns of laminites and four oxygen-related ichnocoenoses in the Bridge Creek in two cores—USGS # 1 Portland from east-central Colorado and Amoco #1 Rebecca K. Bounds from western Kansas—provide a record of both temporal and spatial changes in benthic oxygenation within the distal offshore parts of the Western Interior Seaway.

Paleo-oxygenation histories reconstructed for the Portland core reflect: (1) a broad trend towards decreased benthic oxygenation through the entire Bridge Creek interval; (2) a high-amplitude redox cyclicity that corresponds to limestone/marly shale couplets; and (3) a higher-frequency, lower-amplitude redox cyclicity expressed within the marly shale intervals.

Trends (1) and (2) are well expressed in the Bounds core. However, bioturbated horizons in marly shale intervals are less common, thinner, of lower ichnocoenosis rank, or absent altogether. This pattern indicates that paleo-oxygenation levels were lower at the Bounds locality, at least during clastic-dominated phases of depositional cycles, and may reflect higher productivity and oxygen demand in the eastern part of the basin.

You do not currently have access to this article.

Figures & Tables

Contents

SEPM Concepts in Sedimentology and Paleontology

Stratigraphy and Paleoenvironments of the Cretaceous Western Interior Seaway, USA

Walter E. Dean
Walter E. Dean
U.S. Geological Survey, Denver, Colorado
Search for other works by this author on:
Michael A. Arthur
Michael A. Arthur
Pennsylvania State University, University Park, Pennsylvania
Search for other works by this author on:
SEPM Society for Sedimentary Geology
Volume
6
ISBN electronic:
9781565762299
Publication date:
January 01, 1998

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal