A restudy of podiform chromite deposits and their ore-prospecting vista in China

Abstract：Chromite is an essential component of stainless steel, and China is the largest consumer of stainless steel in the world. However, only a few chromite deposits have been discovered in China, so China must rely almost entirely on imports for this strategic metal. Chromite forms two types of deposits, namely layered and podiform deposits. Chromite deposits in China are all of the podiform type and occur mainly in Tibet, Xinjiang and Inner Mongolia, where they are hosted in mantle peridotites and cumulates sequences in ophiolites. Deep mantle minerals have recently been discovered in-situ in chromite deposits in Tibet and the Polar Urals, which strongly suggests that chromite was formed in the deep mantle rather than in shallow mantle peridotite as suggested by previous researchers. It is held that large chromite deposits can be formed deep in the mantle and be hosted even in small bodies of mantle peridotite. It is thus necessary to reevaluate the current models for chromite formation and to undertake a new investigation into the ophiolite peridotites and chromite deposits in China.