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Landscape evolution at extensional relay zones

Densmore, A.L.; Dawers, N.H.; Gupta, S.; Allen, P.A.; Gilpin, R.

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Authors

N.H. Dawers

S. Gupta

P.A. Allen

R. Gilpin



Abstract

It is commonly argued that the extensional relay zones between adjacent crustal-scale normal fault segments are associated with large catchment-fan systems that deliver significant amounts of sediment to hanging wall basins. This conceptual model of extensional basin development, while useful, overlooks some of the physical constraints on catchment evolution and sediment supply in relay zones. We argue that a key factor in the geomorphic evolution of relay zones is the interplay between two different timescales, the time over which the fault array develops, and the time over which the footwall catchment-fan systems are established. Results of numerical experiments using a landscape evolution model suggest that, in isolated fault blocks, footwall catchment evolution is highly dependent on the pattern and rate of fault array growth. A rapidly linked en echelon fault geometry gives rise to capture of relay zone drainage by aggressive catchment incision in the relay zone and to consequent increases in the rate of sediment supply to the hanging wall. Capture events do not occur when the fault segments are allowed to propagate slowly toward an en echelon geometry. In neither case, however, are large relay zone catchment-fan systems developed. We propose several physical reasons for this, including geometric constraints and limits on catchment incision and sediment transport rates in relay zones. Future research efforts should focus on the timescales over which fault array development occurs, and on the quantitative variations in catchment-fan system morphology at relay zones.

Citation

Densmore, A., Dawers, N., Gupta, S., Allen, P., & Gilpin, R. (2003). Landscape evolution at extensional relay zones. Journal of Geophysical Research, 108(B5), Article 2273. https://doi.org/10.1029/2001jb001741

Journal Article Type Article
Publication Date May 1, 2003
Deposit Date Aug 11, 2010
Publicly Available Date Mar 28, 2024
Journal Journal of Geophysical Research. Solid Earth
Print ISSN 0148-0227
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 108
Issue B5
Article Number 2273
DOI https://doi.org/10.1029/2001jb001741

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Copyright Statement
© 2003 American Geophysical Union. Densmore, A. L. and Dawers, N. H. and Gupta, S. and Allen, P. A. and Gilpin, R. (2003) 'Landscape evolution at extensional relay zones.', Journal of geophysical research : solid earth., 108, 2273, 10.1029/2001JB001741. To view the published open abstract, go to http://dx.doi.org and enter the DOI.





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