Tectonic Control of a Change in Sedimentary Environment at ~10 Ma in the Northeastern Tibetan Plateau

Abstract

Tectonic uplift and climate change play a key role in the evolution of sedimentary systems in terrestrial basins. The Qaidam Basin in the northeastern Tibetan Plateau is well suited for studying these processes because of its location and its thick, continuous sequence of Cenozoic sediments. Unfortunately, however, there is a lack of continuous, well‐dated sedimentary records from the region. In the present study, we combined grain‐size analyses of sediment cores and outcrop samples with structural analysis of seismostratigraphic data from the western Qaidam Basin. The results reveal dramatic shifts in the depositional environment at ~11.5–10 Ma, coeval with the topographic development of the area. Together with paleoclimatic analysis and a conceptual model, we conclude that tectonic movements, rather than climatic changes, were the dominant forcing factor.

Miocene Range Growth Along the Altyn Tagh Fault: Insights From Apatite Fission Track and (U‐Th)/He Thermochronometry in the Western Danghenan Shan, China

“…The proposed rapid exhumation commencing in the middle Miocene coincides with the onset of a suite of significant phenomena along the Altyn Tagh fault: (1) thermochronology on basement rocks along the Altyn Tagh fault (e.g., Jolivet et al, , ; Ritts et al, ; Shi et al, ; Sobel et al, ; Zhuang et al, ); (2) acceleration in sedimentation rate, provenance change and growth strata recorded by paleomagnetic studies in the western Qaidam Basin and along the Altyn Tagh fault (e.g., Chang et al, ; Gilder et al, ; B. Li et al, ; Lu et al, ; Wang, Zhang, Pang, et al, ; W. Zhang et al, ); (3) provenance analyses based on lithofacies variations and detrital zircon U–Pb ages along the Altyn Tagh fault (e.g., F. Cheng et al, , ; Wu, Xiao, Wang, et al, ; Wu, Xiao, Yang, et al, ; Yue et al, ; Zhu et al, ; T. Zhang et al, ); and (4) initiation of growth strata in the basins along the Altyn Tagh fault and western Qaidam Basin revealed by seismic data (e.g., F. Cheng et al, , , ; B. Li et al, ; R. Liu, Allen, et al, ; Yin et al, ).…”

Detailed Processes and Potential Mechanisms of Pliocene Salty Lake Evolution in the Western Qaidam Basin

“…The basin is largely covered by dry salt playas, with only minor desert vegetation and hypersaline lakes (Wang et al, 2012). However, previous studies suggest that a huge Qaidam paleolake might have existed during the Eocene (Wang et al, 2006;Yin et al, 2008a, Yin et al, 2008bZhang et al, 2018;Liang et al, 2021), which expanded from the Oligocene to the Miocene (Yang, 1986;Wu and Xue, 1993), and broke into several small lakes likely during the Quaternary (Han et al, 2014;Lu et al, 2015). However, due to the scarcity of continuously dated sediment records (Lu et al, 2015;Fang et al, 2016), how the Qaidam paleolake evolved into its hyperarid condition remains relatively unknown.…”