Rifting of the Indian passive continental margin: Insights from the Langjiexue basalts in the central Tethyan Himalaya, southern Tibet

Abstract The Triassic tectonic setting of the Tethyan Himalaya in southern Tibet remains controversial and is key to revealing mechanism Neo-Tethys Ocean opening breakup history Gondwana. This paper reports 227–225 Ma mafic volcanic rocks interbedded within sequence Tibet, which were formed a typical passive continental margin setting. basalts are tholeiitic with high TiO2 (3.20–3.38 wt%) moderate MgO (4.05–5.40 contents exhibit enrichment light rare earth elements weak negative Nb, Ta, Eu, Ti anomalies. These geochemical compositions, combined uniform whole-rock ?Nd(t) (+1.50 +2.70) values, indicate that magmas derived by low-degree melting deep-seated garnet source was heterogeneously modified an oceanic island basalt-type component. Given other geological evidence, we propose magmatic evolution during late Paleozoic–Mesozoic generally lithospheric thinning process, is, it evolved from fully developed rift system Late Permian wane Triassic. interpretation further supports hypothesis opened pattern Gondwana Paleozoic initiated thinning. Therefore, subsequent magmatism related upwelling normal asthenospheric materials.