Dynamics and Deposition of Sediment-Bearing Multi- Pulsed Flows and Geological Implication

Ho, Viet Luan; Dorrell, Robert M.; Keevil, Gareth M.; Thomas, Robert E.; Burns, Alan D.; Baas, Jaco H.; McCaffrey, William D.

Abstract

Copyright © 2019, SEPM (Society for Sedimentary Geology) Previous studies on dilute, multi-pulsed, subaqueous saline flows have demonstrated that pulses will inevitably advect forwards to merge with the flow front. On the assumption that pulse merging occurs in natural-scale turbidity currents, it was suggested that multi-pulsed turbidites that display vertical cycles of coarsening and fining would transition laterally to single-pulsed, normally graded turbidites beyond the point of pulse merging. In this study, experiments of dilute, single- and multi-pulsed sediment-bearing flows (turbidity currents) are conducted to test the linkages between downstream flow evolution and associated deposit structure. Experimental data confirm that pulse merging occurs in laboratory-scale turbidity currents. However, only a weak correspondence was seen between longitudinal variations in the internal flow dynamics and the vertical structure of deposits; multi-pulsed deposits were documented, but transitioned to single-pulsed deposits before the pulse merging point. This early transition is attributed to rapid sedimentation-related depletion of the coarser-grained suspended fraction in the laboratory setting, whose absence may have prevented the distal development of multi-pulsed deposits; this factor complicates estimation of the transition point in natural-scale turbidite systems.

Citation

Ho, V. L., Dorrell, R. M., Keevil, G. M., Thomas, R. E., Burns, A. D., Baas, J. H., & McCaffrey, W. D. (2019). Dynamics and Deposition of Sediment-Bearing Multi- Pulsed Flows and Geological Implication. Journal of Sedimentary Research, 8(11), 1127-1139. https://doi.org/10.2110/jsr.2019.62

• Journal Article Type: Article
• Acceptance Date: Aug 21, 2019
• Publication Date: Jan 1, 2019
• Deposit Date: Sep 25, 2019
• Publicly Available Date: Jan 2, 2020
• Journal: Journal of Sedimentary Research
• Print ISSN: 1527-1404
• Publisher: Society for Sedimentary Geology (SEPM)
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 11
• Pages: 1127-1139
• DOI: https://doi.org/10.2110/jsr.2019.62
• Keywords: Multi-pulsed turbidites; Pulsed turbidites; Multi-pulsed flows; Single-pulsed turbidites; Sediment-bearing flows
• Public URL: https://hull-repository.worktribe.com/output/2705164
• Contract Date: Sep 25, 2019