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Million-year lag times in a post-orogenic sediment conveyor

Journal Article


Abstract


  • Understanding how sediment transport and storage will delay, attenuate, and even erase the erosional signal of tectonic and climatic forcings has bearing on our ability to read and interpret the geologic record effectively. Here, we estimate sediment transit times in Australia's largest river system, the Murray-Darling basin, by measuring downstream changes in cosmogenic 26Al/10Be/14C ratios in modern river sediment. Results show that the sediments have experienced multiple episodes of burial and reexposure, with cumulative lag times exceeding 1 Ma in the downstream reaches of the Murray and Darling rivers. Combined with low sediment supply rates and old sediment blanketing the landscape, we posit that sediment recycling in the Murray-Darling is an important and ongoing process that will substantially delay and alter signals of external environmental forcing transmitted from the sediment's hinterland.

Publication Date


  • 2020

Citation


  • Fülöp, R. H., Codilean, A. T., Wilcken, K. M., Cohen, T. J., Fink, D., Smith, A. M., . . . Dunai, T. J. (2020). Million-year lag times in a post-orogenic sediment conveyor. Science Advances, 6(25). doi:10.1126/sciadv.aaz8845

Scopus Eid


  • 2-s2.0-85086369992

Volume


  • 6

Issue


  • 25

Abstract


  • Understanding how sediment transport and storage will delay, attenuate, and even erase the erosional signal of tectonic and climatic forcings has bearing on our ability to read and interpret the geologic record effectively. Here, we estimate sediment transit times in Australia's largest river system, the Murray-Darling basin, by measuring downstream changes in cosmogenic 26Al/10Be/14C ratios in modern river sediment. Results show that the sediments have experienced multiple episodes of burial and reexposure, with cumulative lag times exceeding 1 Ma in the downstream reaches of the Murray and Darling rivers. Combined with low sediment supply rates and old sediment blanketing the landscape, we posit that sediment recycling in the Murray-Darling is an important and ongoing process that will substantially delay and alter signals of external environmental forcing transmitted from the sediment's hinterland.

Publication Date


  • 2020

Citation


  • Fülöp, R. H., Codilean, A. T., Wilcken, K. M., Cohen, T. J., Fink, D., Smith, A. M., . . . Dunai, T. J. (2020). Million-year lag times in a post-orogenic sediment conveyor. Science Advances, 6(25). doi:10.1126/sciadv.aaz8845

Scopus Eid


  • 2-s2.0-85086369992

Volume


  • 6

Issue


  • 25