Central Asian modulation of Northern Hemisphere moisture transfer over the Late Cenozoic

Abstract

Earth’s climatic evolution over the last 5 million years is primarily understood from the perspective of marine mechanisms, however, the role of terrestrial feedbacks remains largely unexplored. Here we reconstruct the last 5 million years of soil moisture variability in Central Asia using paleomagnetism data and isotope geochemistry of an 80 m-thick sedimentary succession at Charyn Canyon, Kazakhstan. We identify a long-term trend of increasing aridification throughout the period, along with shorter-term variability related to the interaction between mid-latitude westerlies and the Siberian high-pressure system. This record highlights the long-term contribution of mid-latitude Eurasian terrestrial systems to the modulation of moisture transfer into the Northern Hemisphere oceans and back onto land via westerly air flow. The response of Earth-surface dynamics to Plio-Pleistocene climatic change in Central Asia likely generated terrestrial feedbacks affecting ocean and atmospheric circulation. This missing terrestrial link elucidates the significance of land-water feedbacks for long-term global climate.

Neogene aridification and lake development in the Issyk‐Kul basin, Kyrgyzstan

“…Ili basin data from Hellwig et al (2018) are not included due to a lack of age constraints. 1–8 show main events, reflected in the stable isotopic records (interpretations are taken from the corresponding articles): (1–2) windward positions of the Tajik (Wang et al, 2020) and Issyk‐Kul (this study and Macaulay et al, 2016) basins due to growing Tian Shan and Pamir; (3) global climatic changes in the Ili basin caused by orbital forcing (Frisch, Voigt, Verestek, et al, 2019), which are not reflected in time‐equivalent records from other basins; (4) change from a windward to leeward position of the Issyk‐Kul basin due to northward growth of Tian Shan (this study); (5) aridification in the Issyk‐Kul basin after Kyrgyz, Kungey and Trans Ili ranges blocked the westerly moisture from reaching the basin (this study); (6) aridification in Central Asia, caused by interactions between the westerlies and the Siberian High (Prud'homme et al, 2021); (7) windward position of the Zaysan basin due to growing Altai (Caves et al, 2017); (8) two records from the Junggar basin are controlled by hypsometry of the drainage basins and do not reflect climatic or tectonic changes (Charreau et al, 2012).…”

“…Other studied windward basins in the Tian Shan and Altai include the Ili basin (Frisch, Voigt, Verestek, et al, 2019; Hellwig et al, 2018; Prud'homme et al, 2021), Tajik basin (Wang et al, 2020), Junggar basin (Charreau et al, 2012) and Zaysan basin (Caves et al, 2017) (Figure 11). In the sedimentary section in the Tajik basin (1800‐m‐thick, 41–23.3 Ma), mudstones and carbonate cement in sandstones were analysed.…”

“…Precipitation in the Tian Shan is seasonally influenced by interactions between the westerlies and the Siberian High (e.g. Aizen et al, 1997; Prud'homme et al, 2021; Schwarz et al, 2017; Zech, 2012). Moisture, delivered by the monsoon, never consistently reached the Tian Shan and did not influence long‐term climate within the range (Caves et al, 2015).…”

Northern hemisphere ice sheet expansion intensified Asian aridification and the winter monsoon across the mid-Pleistocene transition

“…4i). Increasing carbonate δ 13 C values of the Kazakhstan loess sequence suggest that Central Asia aridified across the MPT 60 . Glacial loess deposits in Tarim Basin, which were deposited under the control of mid-latitude Westerlies, became generally coarser across the MPT 18 .…”

Cenozoic Shortening and Propagation in the Eastern Kuqa Fold‐And‐Thrust Belt, South Tian Shan, NW China

“…The uplift of the Tian Shan has affected the geosystem in at least two aspects. On one hand, the significant topography of the Tian Shan has played a key role in the climate evolution of Central Asia since the Late Miocene (Charreau et al., 2009; Miao et al., 2012; Prud’Homme et al., 2021; Sun et al., 2015); on the other hand, the deformation propagated and disrupted adjacent foreland basins, resulting in the development of a series of fold‐and‐thrust belts (FTBs) that encode key deformational and erosional records of the Tian Shan (Figure 1). GPS velocity field indicates that the Western Tian Shan accommodates nearly 40% of the present‐day total convergence between Indian and Eurasia plates (Abdrakhmatov et al., 1996; Reigber et al., 2001; Q. Wang et al., 2001).…”