Fig. 4: 3D geometry of subducting, torn India.
From: The Indian Plate subducting below the Tibet Plateau is tearing apart
a Summary map of SRF results. Southwestern region (pale cyan) has no Tibetan mantle lithosphere (no T-LAB); the thick cyan boundary is shown 100-km wide to capture uncertainty in the location of the SRF mantle suture. Smoothly curved thin white line with thick gray margins is the northern extent of the Indian lower crust at the Moho (crustal front), continuous line from PRF doublet13,14,15, dashed line from H-k Moho mapping16. White stars are earthquakes with hypocenters at 65–100 km depth32. b FWEA23 S-wave tomography dVs (%) at 150 km29. Blue: higher wavespeed than average at 150-km depth, inferred cratonic mantle lithosphere; red: slow wavespeeds, inferred asthenosphere. Dog-legged thick white line with thick gray margins is a helium-boundary line interpreted as a mantle suture32, dashed where poorly constrained. c 3D perspective view of SE Tibet viewed from the northeast, showing cartoon cross-sections at true-scale (no vertical exaggeration) along XX’, YY’ (both parallel to India-Asia convergence direction) and along 31°N (Fig. 3). Wiggly lines are schematic of 3He leaking from hot Neogene mantle lithosphere or subjacent asthenosphere everywhere north of the mantle suture, which is consistent with the >50 km thick low-velocity layer beneath the Tibetan crust48. A transparent shaded-relief map shows sutures, active rifts, and helium boundary, as in (a) and (b).
