Fig. 1

Tectonic reconstructions of the Paleotethys Ocean during the Permian Period. a, b Reconstruction of Scotese and Langford¹⁵. c, d Reconstruction of Domeier and Torsvik². In a and c, reconstructions are shown at 300 Ma, preceding the beginning of the Permian Era by 1 Myr. In b and d reconstructions are shown at the approximate age of the Emeishan eruption (260 Ma). Continental blocks are shown in green, with the exception of the South China block that carries the Emeishan volcanics, shown in orange. The thick black lines in c and d are plate boundaries (mid-ocean ridges, transform faults and subduction zones), with triangles denoting the overriding plate at subduction zones. Subduction zones are drawn at their approximate location based on ref. ¹⁵ in a and b, as these are not available digitally. The solid grey contour indicates a value of five, and the dashed grey contour a value of one in a vote map of the location of LLSVPs in tomography models¹². Orthographic projection centered on 90°E with graticules every 30° and the horizon at 90°