Paleocene latitude of the Kohistan–Ladakh arc indicates multistage India–Eurasia collision

Abstract

We report paleomagnetic data showing that an intraoceanic Trans-Tethyan subduction zone existed south of the Eurasian continent and north of the Indian subcontinent until at least Paleocene time. This system was active between 66 and 62 Ma at a paleolatitude of 8.1 ± 5.6 °N, placing it 600–2,300 km south of the contemporaneous Eurasian margin. The first ophiolite obductions onto the northern Indian margin also occurred at this time, demonstrating that collision was a multistage process involving at least two subduction systems. Collisional events began with collision of India and the Trans-Tethyan subduction zone in Late Cretaceous to Early Paleocene time, followed by the collision of India (plus Trans-Tethyan ophiolites) with Eurasia in mid-Eocene time. These data constrain the total postcollisional convergence across the India–Eurasia convergent zone to 1,350–2,150 km and limit the north–south extent of northwestern Greater India to <900 km. These results have broad implications for how collisional processes may affect plate reconfigurations, global climate, and biodiversity.

Initiation and Evolution of the Shanxi Rift System in North China: Evidence From Low‐Temperature Thermochronology in a Plate Reconstruction Framework

“…To evaluate the competing mechanisms, we place the SRS in a plate-scale context. By 50 Ma, the India-Eurasia continental-continental collision (or more likely, the "soft" collision between India and the intraoceanic Trans-Tethyan arc) was occurring at equatorial to low latitude regions (Figure 8b) (Kapp & DeCelles, 2019;Martin et al, 2020;Patriat & Achache, 1984;Yang et al, 2019). With the presence of a pre-Cenozoic plateau in southern Tibet (Murphy et al, 1997), over 3,000 km away, the present-day northeastern Tibetan Plateau region lay far north of the collision and was subject to SE-oriented crustal extension and rift basin deposition ( Figure 8a) (Fan et al, 2019;Wang et al, 2013Wang et al, , 2016.…”

“…One endmember model attributed the driver to the far-field effect of the India-Eurasia collision, via the lateral escape of crustal fragments along strike-slip faults (Molnar & Tapponnier, 1977;Tapponnier et al, 1982) or driven by lateral flow of the asthenospheric mantle (Liu et al, 2004). The other endmember model argues that the subduction of the Pacific Plate, through variations in convergence rate and/or subduction angle, leads to continental rifting and convective mantle upwelling (e.g., Ma & Wu, 1987;Northrup et al, 1995;Schellart et al, 2019). Other models take both mechanisms into account for the early-Cenozoic rifting in North China (e.g., Ratschbacher et al, 2003;Ye et al, 1987).…”

“…One view proposes a dextral transtension model for the SRS and infers anticlockwise bookshelf rotation of intracontinental blocks in North China (Briais et al, 1993;Clinkscales et al, 2020;Xu & Ma, 1992;Zhang et al, 2018) that is driven by the eastward extrusion of the South China Block along the Qinling Fault zone due to the India-Eurasia collision (Molnar & Tapponnier, 1977;Peltzer et al, 1985). The other view, in contrast, favors an extensional model and attributes the SRS rifting to the Pacific Plate subduction (Ma & Wu, 1987;Yin, 2000).…”

Intermittent Post‐Paleocene Continental Collision in South Asia

“…(a) Greater India model (Figures 1a and 1d), where continuous continental collision with Eurasia consumed >3,000 km of continental lithosphere (Ali & Aitchison, 2005; Lee & Lawver, 1995). (b) Intra‐oceanic Arc model (Figures 1b and 1e; Aitchison et al., 2007; Gibbons et al., 2015; Kapp & DeCelles, 2019; Martin et al., 2020). In this case, a miniature Greater India (∼1,350–2,150 km long) collided with an intra‐oceanic arc instead of Eurasia first, and its collision with Eurasia started at ca.…”

An Initial Collision of India and Asia in the Equatorial Humid Belt

“…The combination of these events may result in a rapid decrease of carbon dioxide in the atmosphere during the early Paleogene that contributes to a long-term cooling of Earth during the Cenozoic. (Yi et al, 2011); the Kohistan-Ladakh arc was constrained by the latest Cretaceous-Paleocene pole obtained from the Khardung volcanics from Ladakh (Martin et al, 2020). Locations of India and Arabia are from the plate construction of van Hinsbergen et al (2019).…”