标题：Integration of zircon and apatite U–Pb geochronology and geochemical mapping of the Wude basalts (Emeishan large igneous province): A tool for a better understanding of the tectonothermal and geodynamic evolution of the Emeishan LIP
摘要：AbstractRadiogenic isotopic dating and Lu–Hf isotopic composition using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) of the Wude basalt in Yunnan province from the Emeishan large igneous province (ELIP) yielded timing of formation and post-eruption tectonothermal event. Holistic lithogeochemistry and elements mapping of basaltic rocks were further reevaluated to provide insights into crustal contamination and formation of the ELIP. A zircon U–Pb age of 251.3 ± 2.0 Ma of the Wude basalt recorded the youngest volcanic eruption event and was consistent with the age span of 251–263 Ma for the emplacement of the ELIP. Such zircons hadεHf(t) values ranging from −7.3 to +2.2, identical to those of magmatic zircons from the intrusive rocks of the ELIP, suggesting that crust-mantle interaction occurred during magmatic emplacement, or crust-mantle mixing existed in the deep source region prior to deep melting. The apatite U–Pb age at 53.6 ± 3.4 Ma recorded an early Eocene magmatic superimposition of a regional tectonothermal event, corresponding to the Indian–Eurasian plate collision. Negative Nb, Ta, Ti and P anomalies of the Emeishan basalt may reflect crustal contamination. The uneven Nb/La and Th/Ta values distribution throughout the ELIP supported a mantle plume model origin. Therefore, the ELIP was formed as a result of a mantle plume which was later superimposed by a regional tectonothermal event attributed to the Indian–Eurasian plate collision during early Eocene.Graphical abstractDisplay OmittedHighlights•Wude basalt forming at 251 Ma recorded the termination of ELIP volcanic volcanism.•Wude basalt documented an early Eocene overprinting attributed to Indian-Eurasian plate collision.•Nb/La and Th/Ta contour maps support a mantle plume model origin.
关键词：KeywordsenEmeishan basaltZircon and apatiteGeochronologyLu–Hf isotopeEarly Eocene superpositionIndian–Eurasian plate collision
