The Emeishan Large Igneous Province comprises voluminous flood basalts and spatially associated mafic-ultramafic intrusions. In the Pan-Xi region, SW China, a number of gabbroic intrusions are dated at ～260 Ma, same as the previous reported ages for the ELIP, and host some giant Fe-Ti-V oxide deposits. Unlike the oxide deposits in classic layered intrusions, such as the Bushveld Complex, those in the Pan-Xi region occur as layers and/or lenses within the gabbros and are generally concentrated in the lower parts of the intrusions. Available geochemical evidence suggests that the intrusions were formed from highly evolved Fe-Ti-Vrich ferrogabbroic or ferropicritic magmas. The magmas were further enriched in Fe-Ti-V after separation of Si-rich magmas which formed the syenitic intrusions. Ore textures and associated mineral assemblages indicate that the orebodies were formed by late-stage crystallization of V-rich titanomagnefite from oxide liquids. The abundant accessory hydrous phases suggest that addition of fluids from upper crustal rocks might have induced the separation of the immiscible oxide melts and subsequently gave rise to the oxide orebodies.%峨嵋山大岩浆省由大量的溢流玄武岩及其伴生的镁铁和超镁铁侵入岩组成.攀西地区的一些层状辉长岩体形成于260 Ma,与早期报道的峨嵋山大岩浆省的年代相同.这些岩体中含有巨大的钒钛磁铁矿床,矿体呈似层状及透镜状产在层状辉长岩体的下部层位,不同于典型的层状岩体(如布什维尔德岩体)的磁铁矿床.地球化学资料表明,攀西地区含磁铁矿的岩体是从高度演化的基性岩浆中结晶而成,因为富硅的岩浆分离使得母岩浆高度富集铁、钛和钒.相对围岩来说,磁铁矿石形成较晚,是从氧化物矿浆中结晶的产物.矿石中有丰富的含水矿物相,流体的参与对氧化物矿浆的形成有重要的作用.
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