Impact of Quaternary Glaciations on Denudation Rates in North Pamir—Tian Shan Inferred From Cosmogenic ¹⁰Be and Low-Temperature Thermochronology

Author(s)

Anna Kudriavtseva, Alexandru T. Codilean, Edward R. Sobel, Angela Landgraf, Réka-H. Fülöp, Atyrgul Dzhumabaeva, Kanatbek Abdrakhmatov, Klaus M. Wilcken, Taylor Schildgen, David Fink, Toshiyuki Fujioka, Lingxiao Gong, Swenja Rosenwinkel, Silke Merchel, Georg Rugel

Abstract

We explore the spatial and temporal variations in denudation rates in the northern Pamir—Tian Shan region using

¹⁰Be-derived denudation rates from modern (n = 110) and buried sediment (2.0–2.7 Ma; n = 3), and long-term exhumation rates from published apatite fission track (AFT; n = 705) and apatite (U-Th-Sm)/He (AHe; n = 211) thermochronology. We found moderate correlations between denudation rates and topographic metrics and weak correlations between denudation rates and annual rainfall, highlighting complex linkages among tectonics, climate, and surface processes that vary locally. The

¹⁰Be data show a spatial trend of decreasing modern denudation rates from west to east, suggesting that deformation and precipitation control denudation in the northern Pamir and western Tian Shan. Farther east, the denudational response of the landscape to Quaternary glaciations is more pronounced and reflected in our data. Modern

¹⁰Be denudation rates are generally higher than the long-term AFT and AHe exhumation rates across the studied area. In the Kyrgyz Tian Shan, on average, the highest

¹⁰Be denudation rates are recorded in the Terskey range, south of Lake Issyk-Kul. Here, modern denudation rates are higher than

¹⁰Be-derived paleo-denudation rates, which are comparable in magnitude with the long-term exhumation rates inferred from AFT and AHe. We propose that denudation in the region, particularly in the Terskey range, remained relatively steady during the Neogene and early Pleistocene. Denudation increased due to glacial-interglacial cycles in the Quaternary, but this occurred after the onset and intensification of the Northern Hemisphere glaciations at 2.7 Ma.

Organisation(s)

Isotope Physics

External organisation(s)

Australian Nuclear Science and Technology Organisation (ANSTO), Helmholtz-Zentrum Dresden-Rossendorf, Universität Potsdam, University of Wollongong, National Academy of Science of Kyrgyz Republic, Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum, Centro Nacional de Investigación sobre la Evolución Humana (CENIEH)

Journal

Journal of Geophysical Research: Earth Surface

Volume

128

No. of pages

23

ISSN

2169-9003

DOI

https://doi.org/10.1029/2023JF007193

Publication date

12-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

105105 Geochemistry, 105127 Geochronology, 104002 Analytical chemistry, 104020 Radiochemistry

Keywords

ASJC Scopus subject areas

Earth-Surface Processes, Geophysics

Portal url

https://ucrisportal.univie.ac.at/en/publications/413f0896-2c06-43a9-b426-d4f0b731f4df