Early Permian Qiangtang flood basalts, northern Tibet, China: A mantle plume that disintegrated northern Gondwana?

Abstract The Qiangtang flood basalt province (QFBP) was recently recognized in northern Tibet, China. It erupted during the Sakmarian–Kungurian and covered an area of > 6.84 × 10 5  km 2 , reaching a maximum thickness of 1.5–2.0 km. The Qiangtang basalts have ocean-island basalt (OIB)-type trace element patterns, with enrichments of light rare-earth elements (LREEs) and Ti–Nb–Ta relative to similarly incompatible elements, as well as exhibiting no Eu-anomalies. The basalts show medium to high Sr and Pb isotopic ratios, and consistently positive e Nd (t). Strong correlations between Mg index, and major and trace elements indicate that the basalts have experienced fractional crystallization of clinopyroxene and olivine, and may have been generated by partial melting of an OIB-type mantle plume source with negligible crustal contamination. Similar early Permian basalts are also present in the Lhasa terrane, South Tibet–northern India, the Sanjiang area, and the Tarim basin. These basalts have an estimated original volume of > 7.51 × 10 5  km 3 , spread over an area of > 9.84 × 10 5  km 2 . We propose that the large-scale eruption of these flood basalts was related to a Sakmarian–Kungurian mantle plume that possibly initiated the disintegration of northern Gondwana and the formation of the Tethys oceans.