A synthesis of mineralization style and regional distribution and a proposed new metallogenic model of Mesozoic W-dominated polymentallic deposits in South China

Abstract South China hosts more than 80% W reserves of China and about 50% of the world, with thousands of world-class W deposits of various types. Recently, more and more giant W deposits have been discovered in both the Nanling region to the south and the Yangtze River region to the north, such as the Zhuxi, Dahutang, Pangushan, and Taoxikeng deposits. In this paper, based on previous publications and new exploration results of the W deposits in South China, the majority of such deposits are reviewed, and are divided into 8 types: quartz-vein, skarn, greisen, porphyry, granite veinlet-disseminated, fractural-hydrothermal, stratabound, and weathering-placer types. Those deposits are closely related to the widely-distributed granitoids.These ore-bearing granitoids typically belong to S-type or highly-fractionated I-type metaluminous-peraluminous calc-alkaline granitic magma series. The magma fractionation degrees are generally increased from those associated with skarn-type W deposits to those with veinlet-disseminated deposits. Crust materials played a key role in the formation of these W-mineralized granites, and also contributed to the various associated metals, such as W-Cu, W-Sn, W-Bi, W-Mo, and W-Be. According to the temporal-spatial association of W deposits with tectono-thermal events in South China, three metallogenic belts can be outlined for future exploration: Nanling W metallogenic Belt (NLB) (170∼150 Ma), Eastern Yangtze W metallogenic Belt (EYB) (150∼120 Ma), and Southeast Coast W metallogenic Belt (SCB) (120∼80Ma). According to the deep crustal structure features of these W metallogenic belts combined with characteristics of different W mineralization types, a generic model is proposed for the formation of the Mesozoic W deposits in South China. During the Mesozoic, from the southeast coast to the inland, the South China block experienced the west-toward subduction, retreating and conversion of the paleo-Pacific plate. Furthermore, deep faults in different areas enhance the local crust-mantle interaction, and W deposits types and temporal-spatial distribution of Mesozoic W deposits in different belts have good correspondence to the deep processes.