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Distributed deformation around the eastern tip of the Kunlun fault

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Abstract

Whether active strain within the Indo-Asian collision zone is primarily localized along major strike-slip fault systems or is distributed throughout the intervening crust between faults remains uncertain. Despite refined estimates of slip rates along many of the major fault zones, relatively little is known about how displacement along these structures is accommodated at fault terminations. Here, we show that a systematic decrease in left-lateral slip rates along the eastern ~200 km of the Kunlun fault, from >10 mm/year to <1 mm/year, is coincident with high topography in the Anyemaqen Shan and with a broad zone of distributed shear and clockwise vorticity within the Tibetan Plateau. Geomorphic analysis of river longitudinal profiles, coupled with inventories of cosmogenic radionuclides in fluvial sediment, reveal correlated variations in fluvial relief and erosion rate across the Anyemaqen Shan that reflect ongoing differential rock uplift across the range. Our results imply that the termination of the Kunlun fault system is accommodated by a combination of distributed crustal thickening and by clockwise rotation of the eastern fault segments.

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Acknowledgments

We thank Doug Burbank, Marin Clark, Bill Craddock, Alison Duvall, Peter Molnar, Will Ouimet, and members of the SMURF seminar series at Potsdam University for thoughtful feedback regarding this work. Reviews by Xiao Wenjiao, Rasmus Thiede, Soumyajit Mukherjee, and an anonymous reviewer significantly improved the manuscript. We thank Christian Dullo and Monika Dullo for their editorial efforts. Our research was supported by the Tectonics program of the National Science Foundation (EAR-0229955) and by a NASA Graduate Research Program Fellowship. Kirby thanks the Alexander von Humboldt Foundation for support during the completion of this manuscript.

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Kirby, E., Harkins, N. Distributed deformation around the eastern tip of the Kunlun fault. Int J Earth Sci (Geol Rundsch) 102, 1759–1772 (2013). https://doi.org/10.1007/s00531-013-0872-x

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