Late Neogene climatic features recorded by isotope records in the Issyk Kul basin, Kyrgyzstan.
- 1Institute of Geosciences, University of Potsdam, Potsdam-Golm, Germany (kudriavt@uni-potsdam.de)
- 2School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
- 3Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, Germany
- 4Department of Earth Sciences, Syracuse University, Syracuse, NY, USA
- 5Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- 6Institute of Geosciences, Goethe University, Frankfurt am Main, Germany
- 7Institute of Geology, National Academy of Sciences, Bishkek, Kyrgyzstan
- 8Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, Australia
We present two carbonate oxygen and carbon isotope records from late Miocene – early Pleistocene stratigraphic sections from the southern flank of the Issyk Kul basin, Kyrgyz Tien Shan. The two sections are 700 and 500 m thick and composed of fluvial and lacustrine sediments. They were dated using magnetostratigraphy (Roud et al., G-Cubed, in review) and 26Al/10Be isochron burial dating (presented here).
Carbonate stable isotope data is useful for reconstruction of climate in Asia over the Cenozoic. Oxygen isotopes are commonly used to detect moisture sources and their interaction with topography. Pedogenic carbon isotopes are used to reconstruct past atmospheric CO2 levels or the spread of C4 vegetation.
The environment of Central Asia is primarily affected by the northern mid-latitude westerlies − winds transporting moisture eastward across Eurasia. Issyk Kul basin is situated on the windward side of the northern Tien Shan. Published data suggest that the Tien Shan mountain ranges interacted with the westerlies since late Oligocene and reorganized Central Asian climate during Neogene (Caves et al., 2017; Charreau et al., 2012; Macaulay et al., 2016; Wang, et al., 2020). The amount of existing published paleoclimate data from northern Central Asia is scarce compared to interior China, and therefore the influence of the Tien Shan uplift on climate in Asia during the Cenozoic is poorly reconstructed.
Our data provide new insight into the role of the range and its interaction with the westerlies in forming climate on the windward side of the northern Tien Shan in the late Neogene. We combine our data with published stratigraphically-older sections nearby (Macaulay et al., 2016) to complete the Neogene stable isotope record of the Issyk Kul basin and study how the evolution of the basin influenced regional climate.
Our d18O and d13C values show slightly positive trends, unlike stratigraphically-older data from the Issyk Kul basin. The preliminary interpretation suggests that the circulation pattern within the range was changed in late Miocene possibly reflecting active tectonic uplift northward of the basin and an increase in aridification.
How to cite: Kudriavtseva, A., Sobel, E., Codilean, A., Roud, S., Wack, M., Gilder, S., Hoke, G., Mulch, A., Mikolaichuk, A., Fink, D., Fülöp, R., and Wilcken, K.: Late Neogene climatic features recorded by isotope records in the Issyk Kul basin, Kyrgyzstan. , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12907, https://doi.org/10.5194/egusphere-egu21-12907, 2021.
