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

Uplift of the Tian Shan range modified regional climate during Cenozoic aridification in Central Asia. This study presents facies analyses and Neogene oxygen carbon isotopic records from magnetostratigraphically dated terrestrial sedimentary sections on southern side intermontane Issyk-Kul basin Kyrgyz 26Al/10Be isochron burial ages eastern sides basin. The δ18O δ13C data show a positive ca. 2‰ shift values between 8 7 Ma change negative to trend. is attributed upwind growth Kyrgyz, Kungey Trans Ili (Zaili) ranges, which diverted westerlies, thereby changing windward leeward position, enhancing establishing modern-day spring summer precipitation regime within Two 4 5 constrain onset Sharpyl Dak deposition basin; southward paleocurrent directions there suggest eastward Pliocene. Increased subsidence local tectonically induced river system reorganization led commencement lake formation at Ma, followed by 2 depositional hiatus. transition sandstones Chu group conglomerates group, marking fluvial-alluvial deposits proximal alluvial fan, 2.6–2.8 dating basin, driven either tectonics or Northern Hemisphere glaciation. concludes that late Miocene–Pliocene northward significantly altered environmental conditions range, preventing moisture-bearing westerlies reaching promoting expansion.