Tectonic Uplift of the Yili Basin during the Last Stage of the Late Pleistocene: Evidence from ESR and OSL Dating of Sediments in the Huocheng Area, Xinjiang

Abstract

The Quaternary sediments in the Yili Basin can serve as archives for studying the Cenozoic basin–mountain relationship. In this study, based on typical natural sections and boreholes, the surficial sediments of the Huocheng area were studied, and their sedimentary ages were obtained using the optically stimulated luminescence (OSL) and electron spin resonance (ESR) dating methods. These dates, combined with changes in the sedimentary facies, provided details of the neotectonic movement in the Yili Basin and adjacent areas. By dating sediments from five sections and three boreholes, we determined that the surficial sediments of the Huocheng area were mainly formed in the Late Pleistocene, with scattered instances of Holocene sediments. The surficial sediments mainly consisted of alluvial fan facies, fluvial facies, lacustrine facies, and desert facies. Based on the activity on the Hongshanzui fault and the northern margin fault of the Wusun Mountains, the Huocheng area was uplifted synchronously with the Tianshan Mountains during the last stage of the Late Pleistocene, causing the desert facies sediments to be superimposed on the former paleo–lake sediments.