TY  - JOUR
A1  - Frisch, Konstantin
A1  - Voigt, Silke
A1  - Verestek, Verena
A1  - Appel, Erwin
A1  - Albert, Richard
A1  - Gerdes, Axel
A1  - Arndt, Iris
A1  - Raddatz, Jacek
A1  - Voigt, Thomas
A1  - Weber, Yuki
A1  - Batenburg, Sietske J.
T1  - Long‐period astronomical forcing of Westerlies' strength in Central Asia during miocene climate cooling
T2  - Paleoceanography and paleoclimatology
N2  - The continental expression of global cooling during the Miocene Climate Transition in Central Asia is poorly documented, as the tectonically active setting complicates the correlation of Neogene regional and global climatic developments. This study presents new geochemical data (CaSO4 content, carbonate δ13C and δ18O) from the endorheic alluvial‐lacustrine Aktau succession (Ili Basin, south‐east Kazakhstan) combined with findings from the previously published facies evolution. Time series analysis revealed long‐eccentricity forcing of the paleohydrology throughout the entire succession, split into several facies‐dependent segments. Orbital tuning, constrained by new laser ablation U‐Pb dates and a preexisting magnetostratigraphy, places the succession in a 5.0 Ma long interval in the middle to late Miocene (15.6 to 10.6 Ma). The long‐term water accumulation in the Ili Basin followed the timing of the Miocene Climate Transition, suggesting increased precipitation in the catchment area in response to climate cooling and stronger westerly winds. This was paced by minima of the 2.4 Ma eccentricity cycle, which favored the establishment of a discharge playa (~14.3 Ma) and a perennial lake (12.6 to 11.8 Ma). Furthermore, low obliquity amplitudes (nodes) caused a transient weakening of the westerlies at ~13.7 to 13.5 Ma and at ~12.7 Ma, resulting in negative hydrological budgets and salinization. Flooding of the windward Ili Basin coeval with aridification in the leeward basins suggests that the Tian Shan was a climate boundary already in the middle Miocene. Our results emphasize the impact of climate fluctuations on the westerlies' strength and thus on Central Asian hydrology.
KW  - orbital forcing
KW  - continental climate
KW  - Central Asia
KW  - Miocene cooling
KW  - integrated stratigraphy
Y1  - 2019
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/56898
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-568987
SN  - 2572-4525
VL  - 34
IS  - 11
SP  - 1784
EP  - 1806
PB  - Wiley
CY  - Hoboken, NJ
ER  -