Rapid drift of the Tethyan Himalaya terrane before two-stage India-Asia collision

Abstract

The India-Asia collision is an outstanding smoking gun in the study of continental collision dynamics. How and when the continental collision occurred remains a long-standing controversy. Here we present two new paleomagnetic data sets from rocks deposited on the distal part of the Indian passive margin, which indicate that the Tethyan Himalaya terrane was situated at a paleolatitude of ∼19.4°S at ∼75 Ma and moved rapidly northward to reach a paleolatitude of ∼13.7°N at ∼61 Ma. This implies that the Tethyan Himalaya terrane rifted from India after ∼75 Ma, generating the North India Sea. We document a new two-stage continental collision, first at ∼61 Ma between the Lhasa and Tethyan Himalaya terranes, subsequently at ∼53−48 Ma between the Tethyan Himalaya terrane and India, diachronously closing the North India Sea from west to east. Our scenario matches the history of India-Asia convergence rates and reconciles multiple lines of geologic evidence for the collision.

New Precise Dating of the India‐Asia Collision in the Tibetan Himalaya at 61 Ma

“…Previous studies documented that the India to Asia provenance reversal (IAPR) recorded in sandstones deposited on the Indian passive margin represents a fundamental clue to constrain the timing of initial collision (Garzanti et al., 1987; Hu, Garzanti, Moore, et al., 2015; Najman et al., 2017, 2010). The age of this major geological event has been pin‐pointed in deep‐water turbiditic successions as ∼59–60 Ma (DeCelles et al., 2014; Hu, Garzanti, Moore, et al., 2015; Wang et al., 2011; Wu et al., 2014;), which is consistent with most available geological information excepting the too distant paleolatitude positions of India relative to Asia suggested by paleomagnetic evidence (van Hinsbergen et al., 2012; Yuan et al., 2021).…”

Biostratigraphy and provenance analysis of the Cretaceous to Palaeogene deposits in southern Tibet: Implications for the India‐Asia collision

“…Additionally, recent studies suggest that the IYSZ constrains more than one suture zone (i.e. the existence of more than one ocean Parsons et al., 2020; Yuan et al., 2020), as evinced by ophiolites exhibiting supra‐subduction zone (SSZ) signatures (Guilmette et al., 2009; Hébert et al., 2012; Mahéo et al., 2004).…”

“…Detrital zircon U–Pb age and biostratigraphic data from the southern Tibet reveal that the correlated changes in sediment provenance is consistent with a Palaeocene initiation of either an India–Asia collision or an India‐ intra‐oceanic island arc system collision. In addition, as continental collision is a long and complex process, current models for the India–Asia collision still remain uncertain and further investigations are required to resolve this on‐going debate, including more evidence for or against the presence of more than one subduction zone within the YTSZ and the underplating and accretion records of the Tethyan Himalaya, Greater Himalaya and Lesser Himalaya and their compatibility with the rifting of the Tethyan Himalaya terrane from the India plate prior to the final continental collision (Yuan et al., 2020). The record of post‐80 Ma intra‐oceanic island arc magmatism also needs to be further studied and detailed geological mapping and biostratigraphic analysis needed to establish a regional chronostratigraphic framework in part of the Qiangtang terrane and the northern Himalaya.…”

A record of plume-induced plate rotation triggering seafloor spreading and subduction initiation

“…How far the Indian plate continued northwards around 105 Ma is subject to ongoing debate. On the one hand, the northern Indian continental margin has been proposed to have rifted off India sometime in the Cretaceous 34,63 , but recent paleomagnetic data suggest that this process occurred in the late Cretaceous, well after 100 Ma 64 . Others inferred that the north Indian continent had a passive margin contiguous with oceanic Neotethyan lithosphere since the middle Jurassic or before and continued to a subduction zone below the SSZ ophiolites found in the Himalayan suture zone and the Kohistan arc 35,65,66 .…”