Quantitative kinematic reconstruction of the Tibetan-Himalayan Orogen since 130 Ma

Abstract

The Tibetan-Himalayan Orogen is the largest region of active continental deformation on Earth. Knowledge of the kinematic evolution of this orogenic system is paramount in understanding the dynamics of convergence and continental collision, the development of topography and both regional and global climate changes, as well as the origin of local biodiversity hotspots. Here, we capitalise on the large amount of data published in the last decade to present a new tectonic reconstruction of the Tibetan-Himalayan Orogen since the Cretaceous. We build our reconstruction with high-resolution oceanic spreading records and a thorough review of available data from structural geology, sedimentary provenance and palaeomagnetism, and explicitly resolve continental deformation using the latest advancements in reconstruction software. The reconstruction shows that Tibet was subject to extensive continental deformation, a significant portion of which is related to subduction of the Neotethys Ocean rather than India-Eurasia collision. All available data support a scenario with a single subduction zone along the southern margin of Eurasia since at least 130 Ma and a ∼ 59 Ma collision of the Tethyan Himalaya with Eurasia. We account for the inherent dispersion of palaeomagnetic poles when interpreting data from terranes like the Kohistan-Ladakh Arc and the West Burma Terrane. As a result, the Kohistan-Ladakh Arc is best interpreted as the lateral continuation of the Gangdese Arc on the Lhasa Terrane, while the West Burma Terrane is most likely a forearc sliver that was originally situated off the western margin of Sumatra. Whether the ∼ 2000 km wide crust of Greater India that subducted without a geologic record was entirely continental or partly oceanic cannot be conclusively determined from the geologic record and the tectonic history of the Tibetan-Himalayan Orogen nor that of the adjacent SE Asian Orogen. Finally, our reconstruction provides a quantitative platform for future study on the geodynamics, palaeogeography, palaeoclimate, and biogeography of the Tibetan-Himalayan Orogenic System.