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Sediment flux from an uplifting fault block

Allen, P.A.; Densmore, A.L.

Authors

P.A. Allen



Abstract

The stratigraphy of rift basins is a direct result of sediment liberation and transport through catchment–fan systems whose dynamics are controlled by both external and internal factors. We investigate the response of catchment–fan systems established across an active normal fault to variations in both tectonic and climatic boundary conditions. Numerical experiments show that the ratio of fan area to catchment area provides a sensitive indicator of tectonic activity. A step decrease in fault slip rate results in a delayed response by the catchment–fan systems; the response time is ∼50 kyr for a variety of parameter values. Decreased slip rate also gives rise to an abrupt but transient pulse in sediment discharge from the fans due to a drop in the hangingwall subsidence rate. In contrast, variations in climatic activity, using precipitation rate as a proxy, produce extremely rapid responses throughout the catchment–fan system. Thus, high-frequency climatic changes will overprint lower frequency tectonic variations in the stratigraphic record of fan deposits. Finally, we map out possible combinations of fault geometry, fault slip rate and precipitation rate that allow fan progradation and high rates of sediment discharge from the system.

Citation

Allen, P., & Densmore, A. (2000). Sediment flux from an uplifting fault block. Basin Research, 12(3-4), 367-380. https://doi.org/10.1111/j.1365-2117.2000.00135.x

Journal Article Type Article
Publication Date Jan 1, 2000
Deposit Date Aug 5, 2010
Journal Basin Research
Print ISSN 0950-091X
Electronic ISSN 1365-2117
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 12
Issue 3-4
Pages 367-380
DOI https://doi.org/10.1111/j.1365-2117.2000.00135.x