Formation of Fe-Ti oxide ore deposits associated with flood basalts: A case study on Emeishan Large igneous Province, China
|Leitung:||Prof. Dr. Tong Hou|
|Förderung durch:||Humboldt foundation|
Large igneous provinces (LIPs) represent extremely large volumes of mafic volcanic and/or plutonic rocks that were erupted or emplaced in the upper crust within a short geological time interval. No such deposits were related to flood basalts in large igneous provinces (LIPs) in the past, until the recent discovery that many of the Fe–Ti oxide deposits in the Panzhihua–Xichang (Panxi) region, SW China, are related to the ∼260 Ma Emeishan LIP. Oxide ores hosted as extensive conformable masses in layered mafic–ultramafic intrusions represent world-class resources of Fe, Ti and V. These enigmatic oxide deposits have attracted a substantial number of petrologic and geochemical studies, but the origin of them are still hotly debated as two main models had been proposed for deposit formation, i.e. fractional crystallization and liquid immiscibility. Our primary objective is to advance the understanding of physical and chemical processes leading to the formation of Fe-Ti oxide ores and the reconstruction of the magma plumbing system of the ELIP. The proposed high-precision analytical work represents a critical step towards the better understanding on the origin of LIP and giant Fe-Ti oxide endowment. The research program is subdivided into three tasks with specific objectives, and each task constitutes a coherent set of analysis section. Three major processes that are closely related to the formation Fe-Ti oxide ores will be studied: 1) Formation mechanism of Fe-Ti oxide ore layers; 2) Fractionation of Fe-Mg isotope during the high-temperature magma differentiation; 3) Processes and time scales between replenishment and eruption in ELIP. The projects are closely interconnected and we describe milestones to be reached in order to start specific aspects of tasks. The unique equipment of geochemistry laboratory especially the outstanding analytical and experimental facilities at Leibniz University of Hannover is ideal to elucidate the behavior of trace elements and isotopes.