Structure, age substantiation and tectonic setting of the Lower-Middle Ordovician volcanic-sedimentary and plutonic complexes of the western part of the Kyrgyz Range (Northern Tien Shan)

A new geological framework for the Lower-Middle Ordovician volcanic-sedimentary and plutonic complexes in the western Kyrgyz Range (Northern Tien Shan) reveals their formation within a suprasubduction island arc setting with a thick, heterogeneous basement. The Kentash Formation, dated between Late Tremadocian and Early Darriwilian stages using conodonts and U-Pb zircon dating, consists of dacitic to basaltic volcanic rocks, tuffs, sandstones, and limestone interlayers. Associated ultramafic-gabbro massifs (Kokkiya Complex) are dated to the Late Darriwilian stage. Chemical compositions indicate a suprasubduction environment, while olistostrome deposits suggest thrusting of Cambrian complexes over older strata. The Taldybulak and Kyzylkainar Formations accumulated in back-arc basins and on island arc slopes, providing insights into the tectonic evolution of the region.

Degtyarev, K. E., Tolmacheva, T. Yu., Ryazantsev, A. V., Tret’yakov, A. A., Yakubchuk, A. S., Kotov, A. B., Sal’nikova, E. B., Yakovleva, S. Z., & Gorokhovskii, B. M. (2012). Structure, age substantiation and tectonic setting of the Lower-Middle Ordovician volcanic-sedimentary and plutonic complexes of the western part of the Kyrgyz Range (Northern Tien Shan). Stratigraphy and Geological Correlation, 20(4), 317–345. https://doi.org/10.1134/s0869593812030033