TY  - JOUR
A1  - Roud, Sophie
A1  - Wack, Michael Richard
A1  - Gilder, Stuart A.
A1  - Kudriavtseva, Anna
A1  - Sobel, Edward
T1  - Miocene to early pleistocene depositional history and tectonic evolution of the Issyk-Kul Basin, Central Tian Shan
JF  - Geochemistry, geophysics, geosystems : G 3 ; an electronic journal of the earth sciences
N2  - The Issyk-Kul Basin (Kyrgyzstan), situated in the central Tian Shan Mountains, hosts the largest and deepest mountain lake in Central Asia. Erosion of the surrounding Terskey and Kungey ranges led to the accumulation of up to 4 km of sediment in the adjacent depression. Creation of the basin from regional shortening and uplift likely initiated around the Oligocene-Miocene, yet precise age control is sparse. To better understand the timing of these processes, we obtained magnetostratigraphic age constraints on fossil-poor, fluvio-lacustrine sediments exposed south of Lake Issyk-Kul, that agree well with previous age constraints of the equivalent strata outside the Issyk-Kul Basin. Two 500-650 m thick sections comprised mainly of Chu Group sediments were dated at 6.3-2.8 Ma and 7.0-2.4 Ma (late Miocene to early Pleistocene). Together with reinterpreted magnetostratigraphic constraints from underlying strata, we find that syn-tectonic deposition commenced at similar to 22 Ma with average sedimentation rates <10 cm/ka. Sedimentation rates increased to 10-30 cm/ka at 7 Ma, concurrent with accelerated uplift in the Terskey Range to the south. A deformation event in one section (Kaji-Say) between 5 and 3 Ma together with concurrent shifts of depositional centers throughout the basin signal the onset of substantial uplift of the Kungey Range to the north at similar to 5 Ma. This uplift and deformation transformed the Issyk-Kul area into a closed basin that facilitated the formation of a deep lake. Lacustrine facies deposited around 3 Ma mark the existence of Lake Issyk-Kul by that time.
KW  - Central Asia
KW  - Lake Issyk‐ Kul
KW  - magnetostratigraphy
KW  - Neogene
KW  - Tian
KW  - Shan
Y1  - 2021
U6  - https://doi.org/10.1029/2020GC009556
SN  - 1525-2027
VL  - 22
IS  - 4
PB  - Wiley
CY  - Hoboken, NJ
ER  -