Reduced convergence within the Tibetan Plateau by 26 Ma?

Abstract

Abstract Understanding the dynamics of double‐thickening and uplifting of the Tibetan crust requires constraints on the magnitude and timing of crustal shortening. New elongation/inclination ( E / I )‐corrected paleomagnetic data from ~26–22 Ma sediments indicate that the latitude of southern Tibet in the early Miocene was 31.1/−6.8/+5.2°N, not significantly different from today. This implies that the southern margin of Asia, which was at 21–24°N latitude from the Late Cretaceous to the early Eocene, advanced 8–10° northward between the early Eocene and the latest Oligocene. Our results therefore suggest that at least 900–1100 km of continental shortening and significant regional uplift of the plateau occurred between the early Eocene and late Oligocene. Our results suggest that N‐S intra‐Asian convergence was considerably reduced around 26 Ma, corresponding to a transition from compression to extension within the Tibetan Plateau.