Correlation of Crustal Kinematic Characteristics and the Uplift of the Southeastern Tibetan Plateau During the Paleogene

Abstract The mechanism of the uplift of the southeastern Tibetan Plateau during the Cenozoic is much debated. To address this problem, we conducted a paleomagnetic study of the Eocene sedimentary strata in the Relu Basin, in the southeastern Tibetan Plateau. Two primary magnetic components of Ds = 24.0°, Is = 26.8°, k = 156.8, α95 = 3.5° acquired during ∼48.0–43.0 Ma and Ds = 172.2°, Is = −38.0°, k = 38.6, α95 = 9.8° during ∼43.0–35.0 Ma were isolated. The results combined with previous Paleocene and Eocene paleomagnetic and paleo‐altimetry data sets from the southeastern Tibetan Plateau, revealed a spatio‐temporal correlation between crustal movement and the uplift process of the southeastern Tibetan Plateau. The results showed that the final collision between India and Asia at ∼53.0–47.0 Ma immediately triggered the latitudinal crustal convergence and rotational deformation within the southeastern Tibetan Plateau. Since ∼47.0 Ma the southeastern Tibetan Plateau underwent a coherent crustal rotational pattern, and by at least ∼43.0 Ma, it finished the substantial latitudinal crustal convergence. The crustal movement transformations coincided with the major uplift of the southeastern Tibetan Plateau during ∼47.0–35.0 Ma and the eruption of extensive mafic magmatic rocks across the southeastern Tibetan Plateau and its margin during ∼43.0–33.0 Ma. These spatio‐temporal relationships suggest that the integral uplift of the southeastern Tibetan Plateau was mainly associated with the asthenospheric mantle upwelling and convection resulting from the tearing of the mantle lithosphere of the India Plate beneath the southeastern Tibetan Plateau.