Journal of Asian Earth Sciences 241 (2023) 105477 Available online 9 November 2022 1367-9120/© 2022 Elsevier Ltd. All rights reserved. Geochemistry and petrogenesis of Late Permian basalts from the Sichuan Basin, SW China: Implications for the geodynamics of the Emeishan mantle plume Fanchao Meng a, b, c, * , Yulu Tian a, b, c , Andrew C. Kerr d, * , Wei Wang e , Zhiping Wu a, b, c , Qiang Xu f , Qing Du a, b, c , Yaoqi Zhou a, b, c , Jiaqi Liu g a School of Geosciences, China University of Petroleum (East China), Qingdao 266580, China b Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266061, China c Shandong Provincial Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, China d School of Earth and Environmental Sciences, Cardiff University, Cardiff, Wales CF10 3AT, United Kingdom e Exploration and development Research Institute of Southwest Oil and Gas Field Company, PetroChina, Chengdu 610041, China f School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China g Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China A R T I C L E INFO Keywords: Emeishan mantle plume Outer zone Sichuan Basin basalts petrogenesis of high-Ti basalts Plume-lithosphere interaction ABSTRACT Plume-lithosphere interactions are significant in the formation of Large Igneous Provinces (LIPs). The Permian Emeishan Large Igneous Province (ELIP) is considered to be the result of a mantle plume. The Emeishan flood basalts comprise a major part of the ELIP and they define three zones: the inner, intermediate and outer zones. Both high-Ti and low-Ti basalts are present in the inner zone, whereas only high-Ti basalts are found in the intermediate zone and outer zone. However, there are only sparse outcrops in the outer zone, and so geochemical data on basalts from the outer zone are rare and the role of plume-lithosphere interaction in the petrogenesis of volcanic rocks in the outer zone remains poorly understood. In the Sichuan basin, the Basalt Formation is found between the Permian Maokou Formation limestone and the Longtan Formation marl in some drill cores as well as in outcrops in the basin. This relationship demonstrates that the basaltic layer in the basin is part of the Emeishan flood basalts. These basalts have TiO 2 contents of 3.7–4.2 wt% and Ti/Y ratios of 604–720, being high-Ti sub- alkaline basalts. They display chondrite-normalized rare earth elements (REE) patterns enriched in light rare earth elements (LREE) relative to heavy rare earth elements (HREE) and have elevated large ion lithophile el- ements (LILE) and high field strength elements (HFSE). Lead isotope ratios are high ( 206 Pb/ 204 Pb(t) = 18.102–18.392, 207 Pb/ 204 Pb(t) = 15.578–15.606, 208 Pb/ 204 Pb(t) = 38.410–38.850), and ε Nd (t) values are  0.38 ~ 1.17. Detailed petrology and geochemistry suggest that the high-Ti basalts from the Sichuan Basin did not experience significant contamination of crustal and lithospheric mantle material during the ascent of magma. We infer that these basalts resulted from low-degree melting of the plume mantle source and underwent fractional crystallization of clinopyroxene. The distribution and petrogenesis of the Sichuan Basin basalts in the outer zone are different from those of the basalts in the inner zone and there are clearly different plume-lithosphere in- teractions in different parts of the ELIP. In the inner zone, the temperature of the lithosphere mantle was markedly elevated due to underplating of the mantle plume, causing a substantial quantity of lithosphere mantle melting and the initial formation of low-Ti basalts. This was followed by melting of the mantle plume and the formation of high-Ti basalts. In the outer zone, lower temperatures further from the plume centre were insuf- ficient to generate extensive melting of the lithospheric mantle. Consequently, only the mantle plume melted in the outer zone, resulting in the formation of high-Ti basalts with minimal lithospheric input. * Corresponding authors at: School of Geosciences, China University of Petroleum (East China), Qingdao 266580, China (F. Meng). E-mail addresses: mengfc@upc.edu.cn (F. Meng), kerra@cf.ac.uk (A.C. Kerr). Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes https://doi.org/10.1016/j.jseaes.2022.105477 Received 22 April 2022; Received in revised form 24 October 2022; Accepted 3 November 2022