Constraints on the Timing of Surface Uplift of the Iranian Plateau (Arabia-Eurasian Collision Zone) from Clumped Isotope Thermometry of Early Miocene to Quaternary Lacustrine and Pedogenic Carbonates
Abstract
Orogenic plateaus are extensive, elevated, arid, generally internally drained, morphotectonic provinces of low internal topographic relief that represent a striking and enigmatic feature of Earth's continental landscapes. They are located along convergent plate boundaries and have a profound impact on regional and global climate, erosional processes, local- to far-field deformation mechanisms and the long-term distribution of biomes and biodiversity. Although the paramount role of large orogenic plateaus in shaping our planet is widely appreciated, the question of why, where, and how some orogenic systems develop large plateaus remains a first-order problem in our understanding of lithospheric evolution and orogenic processes.
Here, we present a clumped isotope paleoaltimetry study to document the elevation history of the Iranian Plateau, with the goal of understanding the rates and mechanisms of orogenic plateau rise. This plateau is in the Arabia-Eurasia collision zone, has a mean elevation of ~ 1.8 km, steep margins with mountain peaks higher than 4 km, and experienced surface uplift sometime after the middle Miocene as documented by the occurrence of ca. 17-My-old marine deposits in the plateau interior. Preliminary clumped isotope results for Quaternary carbonate nodules along a regional topographic gradient show a temperature-elevation gradient of 8-10 °C/km that correlates with April-May-June air temperatures. The relationship between Quaternary carbonate formation temperatures and modern temperature suggests that pedogenic carbonate grows after the . Preliminary results from Early Miocene to Quaternary lacustrine and pedogenic carbonates on the plateau suggest that surface uplift must have occurred sometime between 12-11 and 5.5 Ma. The lack of significant crustal shortening and thickening during this time interval and the occurrence of a renewed phase of volcanism by ca. 11 Ma, locally with an alkaline signature, suggests that surface uplift may have been driven by deep-seated processes associated with asthenospheric flow.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T52B..05B
- Keywords:
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- 8125 Evolution of the Earth;
- TECTONOPHYSICS;
- 8169 Sedimentary basin processes;
- TECTONOPHYSICS;
- 8175 Tectonics and landscape evolution;
- TECTONOPHYSICS;
- 8177 Tectonics and climatic interactions;
- TECTONOPHYSICS