东天山晚白垩世—新生代构造隆升与地貌演化OA

[Objective]The Tianshan is an intracontinental orogenic belt reactivated in the Cenozoic by far-field effects of the India-Asia collision.Its Cenozoic tectonic evolution is thus key to understanding intracontinental deformation mechanisms.[Methods]Based on stratigraphic sedimentary characteristics and provenance tracing of a section on the northern margin of the Turpan Basin(south of the Bogda Shan),the Late Cretaceous to Cenozoic tectonic and geomorphic evolution of the East Tianshan and its adjacent region has been constrained.[Results]Field investigations reveal that the Paleocene and lower Oligocene strata in this area consist predominantly of red mudstones,indicating a lacustrine environment and stable tectonic conditions.The uppermost Cretaceous and Eocene strata contain relatively thin conglomerate deposits with small clast diameters,suggesting slight tectonic uplift of the Bogda Shan.In contrast,the upper Oligocene to Pliocene strata are composed of extremely thick,coarse conglomerates,reflecting long-term and intense tectonic activity.Detrital zircon U-Pb ages show that,from the Late Cretaceous to the Oligocene,the northern Turpan Basin continuously received detrital material from the West Tianshan,implying low topographic relief of the Bogda Shan during this period.Since the Miocene,however,the Bogda Shan has become the primary sediment source,indicating its rapid tectonic uplift.[Conclusions]In summary,the Bogda Shan remained tectonically stable with low relief during the Late Cretaceous to Oligocene.Since the late Oligocene,it has undergone intense deformation and rapid uplift,becoming the sole provenance area for the northern Turpan Basin.[Significance]This study refines the Cenozoic tectono-geomorphic evolution of the East Tianshan,thereby contributing to a better understanding of the intracontinental deformation processes resulting from the India-Asia collision.