Depositional processes interact with mobile substrates in nearly all passive-margin settings throughout the world. The interplay between sedimentation and a mobile substrate (e.g., salt layer) results in a complex stratigraphic record, making it difficult to reconstruct basin-fill history. Herein we investigate the dynamic feedback between sediment loading and substrate deformation to understand morphologic change and stratigraphic development. We used simplified tank experiments of a linked fan and terminal-channel system evolving over a deformable substrate. A series of experiments were conducted with controlling variables including mobile substrate thickness, sediment supply rate, and basin slope. Experimental results indicate: (1) an increase in substrate thickness resulted in increased subsidence around the fan that limited sediment transport to its terminal channels, (2) a higher sediment discharge rate on a substrate resulted in faster fan progradation coupled with relatively less subsidence and more sediment transport to terminal channels, and (3) a higher-slope experiment caused the largest amount of sediment transport downstream, while a decrease in basin slope resulted in a larger number of established channels along with a wider fan surface. An analysis of surface processes is also used to determine the expected stratigraphy between a linked fan and terminal-channel system as it interacted with the mobile substrate. We apply the experimental findings to understand the fluvial-dump-wind-redistribute system deposited on top of the Louann Salt layer in the eastern part of the Late Jurassic Gulf of Mexico basin.
Bibliographical noteFunding Information:
This study was supported by a research grant to W.K. from the Jackson School of Geosciences at the University of Texas at Austin and by Shell Exploration & Production Company. This paper greatly benefited from comments by Kyle Straub, Rob Duller, and an anonymous reviewer. Data for this paper are available through the Sediment Experimentalists Network (SEN) Knowledge Base.
All Science Journal Classification (ASJC) codes