Lake overspill and onset of fluvial incision in the Iranian Plateau: Insights from the Mianeh Basin
Abstract
Orogenic plateaus represent a prime example of the interplay between surface processes, climate, and tectonics. This kind of an interplay is thought to be responsible for the formation, preservation, and, ultimately, the destruction of a typical elevated, low-internal relief plateau landscape. Here, we document the timing of intermontane basin filling associated with the formation of a low-relief plateau morphology, followed by basin opening and plateau-flank incision in the northwestern Iranian Plateau of the Arabia–Eurasia collision zone. Our new U–Pb zircon ages from intercalated volcanic ashes in exposed plateau basin-fill sediments from the most external plateau basin (Mianeh Basin) document that the basin was internally drained at least between ∼7 and 4 Ma, and that from ∼5 to 4 Ma it was characterized by an ∼2-km-high and ∼0.5-km-deep lake (Mianeh paleolake), most likely as a result of wetter climatic conditions. At the same time, the eastern margin of the Mianeh Basin (and, therefore, of the Iranian Plateau) experienced limited tectonic activity, as documented by onlapping sediments and smoothed topography. The combination of high lake level and subdued topography at the plateau margin led to lake overspill, which resulted in the cutting of an ∼1-km-deep bedrock gorge (Amardos) by the Qezel-Owzan River (QOR) beginning at ∼4 Ma. This was associated with the incision of the plateau landscape and the establishment of fluvial connectivity with the Caspian Sea. Overall, our study emphasizes the interplay between surface and tectonic processes in forming, maintaining, and destroying orogenic plateau morphology, the transitional nature of orogenic plateau landscapes on timescales of 10^6 yr, and, finally, the role played by overspilling in integrating endorheic basins.
Additional Information
© 2017 Elsevier B.V. Received 27 November 2016, Revised 10 April 2017, Accepted 11 April 2017, Available online 29 April 2017. GH was supported by the German Academic Exchange Service. PB was supported by the German Research Foundation (DFG BA 4420/2-1 and BA 4420/2-2) and the Darius Program. We would like to thank T. Schildgen and A. Landgraf for their comments and help with the celerity calculation. The authors acknowledge A. Forte and two anonymous reviewers for constructive comments.Additional details
- Eprint ID
- 78232
- Resolver ID
- CaltechAUTHORS:20170615-073856752
- Deutscher Akademischer Austauschdienst (DAAD)
- BA 4420/2-1
- Deutsche Forschungsgemeinschaft (DFG)
- BA 4420/2-2
- Deutsche Forschungsgemeinschaft (DFG)
- Darius Program
- Created
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2017-06-22Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field