Discussion on genesis of different types of minerals in the podiform chromitite deposit and constraint on the metallogenic process of the deposit
摘要
<p indent="0mm">Chromitite is one of the strategic ores in urgent need in China. Podiform chromitite occurred in ophiolite is the main source of chromium resource in China, and is also the focus of exploration and research. In this paper, we have emphatically discussed the genesis of different types of minerals in podiform chromitite ores, especially those exotic minerals documented in recent years, and the constraint on the source of ore-forming materials and the physicochemical conditions for the mineralization of the podiform chromitite deposit. Podiform chromitite orebodies, occurred in ophiolites with obvious zonal or stratified structures, include disseminated chromitite ones in the dunitic mantle transition zone and massive chromitite ones in the mantle harzburgite below the Moho. In addition, various types of mineral assemblages in the podiform chromitite orebody, especially minerals of diamond, coesite and Qingsongite, had retained abundant information of the deep mantle, and indicated the cross-lithospheric scaled metallogenic conditions of temperature, pressure and oxygen fugacity. The study on the genesis of different types of minerals in chromitite ores has expanded our understanding of compositions and physicochemical states of deep mantle materials, and the cycling mechanism of crustal and mantle materials, and meanwhile has improved our understanding of the metallogenic process and mechanism of the podiform chromitite deposit.