Sticky stuff: redefining bedform prediction in modern and ancient environments

Schindler, Robert J.; Parsons, Daniel R.; Ye, Leiping; Hope, Julie A.; Baas, Jaco H.; Peakall, Jeff; Manning, Andrew J.; Aspden, Rebecca J.; Malarkey, Jonathan; Simmons, Steve; Paterson, David M.; Lichtman, Ian D.; Davies, Alan G.; Thorne, Peter D.; Bass, Sarah J.

Abstract

The dimensions and dynamics of subaqueous bedforms are well known for cohesionless sediments. However, the effect of physical cohesion imparted by cohesive clay within mixed sand-mud substrates has not been examined, despite its recognized influence on sediment stability. Here we present a series of controlled laboratory experiments to establish the influence of substrate clay content on subaqueous bedform dynamics within mixtures of sand and clay exposed to unidirectional flow. The results show that bedform dimensions and steepness decrease linearly with clay content, and comparison with existing predictors of bedform dimensions, established within cohesionless sediments, reveals significant over-prediction of bedform size for all but the lowermost clay contents examined. The profound effect substrate clay content has on bedform dimensions has a number of important implications for interpretation in a range of modern and ancient environments, including reduced roughness and bedform heights in estuarine systems and the often cited lack of large dune cross-sets in turbidites. The results therefore offer a step change in our understanding of bedform formation and dynamics in these, and many other, sedimentary environments.

Citation

Schindler, R. J., Parsons, D. R., Ye, L., Hope, J. A., Baas, J. H., Peakall, J., Manning, A. J., Aspden, R. J., Malarkey, J., Simmons, S., Paterson, D. M., Lichtman, I. D., Davies, A. G., Thorne, P. D., & Bass, S. J. (2015). Sticky stuff: redefining bedform prediction in modern and ancient environments. Geology, 43(5), 399-402. https://doi.org/10.1130/g36262.1

• Journal Article Type: Article
• Acceptance Date: Feb 11, 2015
• Publication Date: 2015-05
• Deposit Date: Apr 10, 2015
• Publicly Available Date: May 31, 2015
• Journal: Geology
• Print ISSN: 0091-7613
• Publisher: Geological Society of America
• Peer Reviewed: Peer Reviewed
• Volume: 43
• Issue: 5
• Pages: 399-402
• DOI: https://doi.org/10.1130/g36262.1
• Keywords: Sediments, Bedforms
• Public URL: https://hull-repository.worktribe.com/output/372166
• Publisher URL: http://geology.geoscienceworld.org/content/early/2015/03/27/G36262.1.abstract
• Additional Information: Copy of article: Robert J. Schindler, Daniel R. Parsons, Leiping Ye, Julie A. Hope, Jaco H. Baas, Jeff Peakall, Andrew J. Manning, Rebecca J. Aspden, Jonathan Malarkey, Steve Simmons, David M. Paterson, Ian D. Lichtman, Alan G. Davies, Peter D. Thorne, and Sarah J. Bass. Sticky stuff: Redefining bedform prediction in modern and ancient environments. Geology, May 2015, v. 43, p. 399-402, first published on March 27, 2015, doi:10.1130/G36262.1
• Contract Date: Apr 10, 2015