Climate evolution from the Miocene to the present in central and southeastern Kazakhstan: Evidence from Aktau Mountain and Kushuk localities

Reconstructing past climate dynamics in Central Asia is essential for understanding the Cenozoic evolution of ecosystems and regional climate patterns. This study presents a comparative paleoclimate analysis of two coeval Early Miocene floras from Kazakhstan: Aktau Mountain (also known as Dzhungar Aktau, Ili Depression, Southeastern Kazakhstan) and Kushuk (Turgai Depression, Central Kazakhstan). Using the Coexistence Approach (CA), we reconstructed key climatic parameters including mean annual temperature (MAT), coldest and warmest month temperatures (CMT, and WMT), and mean annual precipitation (MAP). The results indicate that both regions experienced warm and humid conditions during the Miocene (MAT ~۱۴ °C, and MAP ~۹۰۰–۱۰۰۰ mm), favorable for the development of forested ecosystems. In contrast, paleoclimate simulations from CHELSA TraCE۲۱k reveal that during the Last Glacial Maximum (~۲۱ ka) both localities were characterized by colder and drier conditions (MAT < ۰ °C, and MAP ۸۸–۳۵۰ mm). Modern climate assessments show strong discrepancies between global climate models (CHELSA v۲.۱), which significantly overestimate temperature and precipitation, and regional meteorological data (Kazhydromet), documenting a strongly continental and arid climate (MAT ۱۱.۸ °C, MAP ۲۱۸ mm in Aktau; and MAT ۲.۵ °C, MAP ۲۷۵ mm in Kushuk). Our findings highlight a long-term climatic trajectory from humid Miocene conditions through arid Pleistocene environments to the modern sharply continental climate of Kazakhstan. The study emphasizes the importance of integrating paleobotanical evidence, global climate models, and observational meteorological datasets to achieve reliable reconstructions of the past and present climate dynamics in Central Asia.

کلیدواژه ها:

climate dynamics ، paleoclimate reconstruction ، Miocene ، Kazakhstan ، Coexistence Approach