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Impact of Quaternary glaciations on denudation rates in the Kyrgyz Tian Shan inferred from cosmogenic 10Be and low-temperature thermochronology

We present 10Be-derived denudation rates from modern (n = 54) and buried sediment dated to 2.0–2.7 Ma (n = 3), and exhumation rates derived from published apatite fission track (AFT; n = 296) and apatite (U-Th-Sm)/He (AHe; n = 125) thermochronology from the Kyrgyz Tian Shan. Modern 10Be denudation rates are generally higher than the long-term AFT and AHe exhumation rates. On average, the highest 10Be denudation rates are recorded in the Terskey range, south of Lake Issyk-Kul. Here, 10Be-derived denudation rates from 2.0–2.7 Ma are comparable in magnitude with the AFT- and AHe-derived long-term exhumation rates, but modern 10Be-derived denudation rates are higher. We propose that denudation in the Kyrgyz Tian Shan, particularly in the Terskey range, remained relatively steady during the Neogene and early Pleistocene and increased after the onset and intensification of the Northern Hemisphere glaciations at 2.7 Ma due to glacial-interglacial cycles. Comparison with published data from the Pamir–Tian Shan region shows a spatial trend of decreasing modern denudation rates from west to east and an increase in the difference in magnitude between long-term exhumation rates and modern 10Be-derived denudation rates, suggesting that deformation controls denudation in the Pamir and Western Tian Shan, while farther east, the denudational response of the landscape to Quaternary glaciations becomes detectable by 10Be. We also find moderate correlations between modern denudation rates and topographic metrics and weak correlation between denudation rate and annual rainfall, highlighting complex linkages among tectonics, climate, and surface processes that vary locally.

Details

Author
Anna Kudriavtseva1, Alexandru T. Codilean2, Edward R. Sobel3, Angela Landgraf4, Réka-H. Fülöp5, Atyrgul Dzhumabaeva6, Kanatbek Abdrakhmatov6, Klaus M. Wilcken7, Taylor Schildgen8, David Fink7, Toshiyuki Fujioka9, Swenja Rosenwinkel3, Silke Merchel10, Georg Rugel10
Institutionen
1Institute of Geosciences, University of Potsdam, Germany;School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia; 2School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia;ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of Wollongong, Australia; 3Institute of Geosciences, University of Potsdam, Germany; 4Institute of Geosciences, University of Potsdam, Germany;NAGRA, Switzerland; 5School of Earth, Atmospheric and Life Sciences, University of Wollongong, Australia;Australian Nuclear Science and Technology Organisation (ANSTO), Australia; 6Institute of Seismology, National Academy of Science of Kyrgyzstan, Kyrgyzstan; 7Australian Nuclear Science and Technology Organisation (ANSTO), Australia; 8GFZ German Research Centre for Geosciences, Germany;Institute of Geosciences, University of Potsdam, Germany; 9Australian Nuclear Science and Technology Organisation (ANSTO), Australia;Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Spain; 10Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Germany
Veranstaltung
GeoBerlin 2023
Datum
2023
DOI
10.48380/ytyh-t254

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