Discussion on genesis process and deep prospecting breakthrough of Luobusa chromitite, Tibet

The chromitite bottleneck has been going on for many years in China. In October 2015, Bureau of Land and Resources of Tibet announced the discovery of a 200 million tons of massive chromite deposit in deep exploration at Luobusa in Tibet, which achieved a major breakthrough in China's chromite prospecting, and the direction of finding more chromite deposits in the future was also pointed out. The podform chromite produced in the ophiolitic mantle peridotite is the main source of chromium. The study of podiform chromite mineralization and mantle peridotite is necessary for further finding the chromite deposit and relieve the bottleneck of the chromitite resources in China. Podiform chromite produced in the ophiolite is the main source of chromium and an important strategic resource for China. Research on the genesis of the podiform chromitite and mantle peridotite is necessary for further finding the chromite deposit and relieve the bottleneck of the chromitite resources in China. With the discovery of deep minerals such as diamonds in podiform chromite and mantle peridotites in recent years, researchers have also begun to question the theory of formation of podiform chromite. With the first discovery of 200 million tons of massive chromite orebody, the new understanding that podiform chromite is formed in the depth was raised, and its formation process mainly has gone through four stages. The crust and oceanic crust material of the early subduction to the mantle transition zone (410-660 km) is dehydrated and dismembered, and the heat and fluid produced by the transition zone contribute to the melting of the mantle and the release and aggregation of chromium. The chromitite ore slurry is driven by the mantle plume and is transported to the top of the transition zone for condensation and consolidation. The authors have reached the conclusion that the formation of ophiolites is a mutli -stage process involving subduction of lithospheric slabs into the transition zone, crystallization of chromian spinel and some massive chromitites at depth, incorporation of UHP and highly reduced phases into the chromitites, and entrapment of oceanic lithospheric slabs above subduction zones where they undergo varying degrees of interaction or reaction with MORB melts and SSZ melts. Several large massifs in the western part of the Yarlung Zangbo suture are similar to Luobusa in many aspects. They have experienced the same tectonic setting and the mineralization of podiform chromite, and there is a large prospecting space.