Geology and geochemistry of molybdenum deposits in the Qinling Orogen, P R China / Геология и геохимия месторождений молибдена в орогене Циньлин, Китай

Molybdenum (Mo) is a transition metal with an atomic number of 42 and a relative atomic mass of 95.95. Important isotopes are 95Mo, 96Mo, and 98Mo. Molybdenum has a high melting point of 2623
C and one of the lowest coefficients of thermal expansion among commercially used metals. It readily forms hard, stable carbides in alloys and is widely used in steel alloys, including high-strength alloys and superalloys. Molybdenum was discovered in 1781 by Peter Jacob Hjelm and the name is from the Greek “molybdos,” which means “lead,” because it was often confused

with lead. Details on the chemistry and uses of molybdenum can be found at www. rsc.org/periodic-table/element/42/molybdenum.

China is the most important molybdenum producer in the world, with a reserve of ~25 Mt Mo metal. According to the Mineral Commodity Summaries 2018 published by the U.S. Geological Survey, it contributed nearly half of the molybdenum production in 2016 and 2017. It also has the largest identified molybdenum resources.

The Qinling Orogen in central China ranks as one of the most important Mo provinces in the world. It contains six giant Mo deposits (each with Mo metal reserve of >0.5 Mt) and tens of small (<0.01 Mt), medium (0.010.1 Mt), and large (0.10.5 Mt) deposits, with a total reserve of ~6 Mt Mo metal. All the giant Mo deposits are associated with porphyry or porphyry-skarn systems. Instead of the commonly accepted magmatic arc or back-arc rift that favors development of Mo deposit, the Qinling Orogen is a complex tectonic collage built through the closure of the northernmost Paleo-Tethys and the suturing of the Yangtze and the North China cratons. Detailed studies reveal that the porphyry Mo deposits in the Qinling Orogen also show contrasting geological and geochemical characteristics from counterparts in magmatic arc or back-arc rift. In addition, a number of high-grade, variably sized Mo deposits were recently discovered in quartz or fluorite vein systems, which expands our understanding of Mo ore formation. It is from this point of view that there is a need for a comprehensive publication to provide essential facts about the geological and geochemical features of these Mo deposit. This book contains seven chapters. <...>