Crustal Clockwise Rotation of the Southeastern Edge of the Tibetan Plateau Since the Late Oligocene

Abstract

Figure 1a). Oblique-subduction of the Indian Plate beneath the West Burma Block, southeastern Tibetan Plateau uplifting, formation of the EHS, crustal lateral extrusion and clockwise rotation, and tectonic evolution of strike-slip fault systems are major Cenozoic tectonic events of Southeast Asia. The coherent compression between the Indian Plate and Eurasia was suggested to provide the driving force for significant crustal clockwise rotational extrusion from the southeastern Tibetan Plateau, which controlled the Cenozoic tectonic evolution of strike-slip faults systems in

Post‐50 Ma Evolution of India‐Asia Collision Zone From Paleomagnetic and GPS Data: Greater India Indentation to Eastward Tibet Flow

“…Considering that the crustal flow around the EHS started ∼15-10 Ma (e.g., Ge et al, 2015;Royden et al, 2008), and currently show a geodetic rotation rate of 1-2°/Ma on central Indochina, Gan et al (2021) estimated that this patter may have induced a paleomagnetic rotation of ∼11°CW. This value agrees with the slight CW or insignificant paleomagnetic rotations documented for Plio-Pleistocene localities by few authors (e.g., Li, Deng et al, 2013;Li et al, 2015;Pellegrino et al, 2018;Tong et al, 2021; Zhu et al, 2008). However, numerous paleomagnetic rotations of both senses occur from W to N-NE Tibet, where a CCW geodetic rotation rate is observed.…”

“…Geologic and paleomagnetic data document that the middle to late Mesozoic tectonic evolution of Tibet is mainly governed by the accretion of several terranes, such as Qiangtang, Lhasa, and Tethyan Himalaya (Yin & Harrison, 2000), whereas since ∼50–30 Ma tectonism has been driven by the northward indentation of EHS (Speranza et al., 2019; Tong et al., 2021), plateau growth and collapse (Yin, 2000) and Neo‐Tethys subduction below Indochina (Hall, 2012). According to paleogeographic reconstructions, the Indian plate separated from Madagascar at ∼90 Ma (Copley et al., 2010; van Hinsbergen et al., 2011; Figure 4a), and the first Neo‐Tethyan ophiolites were obducted on the Himalayan realm during late Cretaceous‐early Cenozoic, in agreement with the age of the first collision with the “Proto‐EHS” corner (Dai et al., 2013; Ding et al., 2005; Figure 4b).…”

Initiation of Clockwise Rotation and Eastward Transport of Southeastern Tibet Inferred from Deflected Fault Traces and GPS Observations

“…Otofuji et al (2010) suggested that these regions with large paleomagnetic declinations underwent rotation when they lay near the eastern syntaxis, and subsequently were displaced southeastward, where GPS data show that only slow rotation occurs today. In a review of paleomagnetic data from Yunnan and surrounding regions, Tong et al (2021) concluded that rotation began since ca. 25.7 ± 2.5 Ma at a higher rate than occurs today, despite scatter in amounts of rotation.…”

Upper Crustal Collapse Reconstructed the Topography and Remodeled the Fault System of the Chuandian Fragment in the Southeastern Edge of the Tibetan Plateau, Evidenced by Anisotropy of Magnetic Susceptibility Data Sets

“…The directions of the maximum principal compressional stress and paleo‐declinations are significantly correlated to the longitudes of the sampling sections around the EHS, with the best‐fit correlation coefficients ( R ) of 1.0000 and 0.9029, respectively. The northeastward‐advancing EHS compressed the southeastern edge of the Tibetan Plateau, which drove differential crustal clockwise rotation around the EHS since ∼28.0 Ma, producing the variation of the paleo‐declinations (S. H. Li et al., 2017; Tong, Yang, Gao, et al., 2015; Tong et al., 2021). The consistent trend of variation of the paleo‐declinations and the maximum principal compressional stress indicates that the maximum principal compressional stress around the EHS was imposed by the continuous northeastward indentation of the EHS into Eurasia, since ∼28.0 Ma.…”