Petrogenesis of the Jurassic adakitic rocks in Gan‐Hang Belt South China: Response to the Palaeo‐Pacific Plate oblique subduction

Abstract

To explain the roughly contemporary magmatic activities between Cathaysia Block and both sides of the Jiangnan Orogenic Belt, we discussed the magmatic‐ore related and closely compressive tectonism in the Gan‐Hang Belt. Also, we compared the Yongping Pluton and Yinshan volcanic‐plutonic rocks in northeastern Jiangxi, and Huangshitan and other plutons in the northern Zhejiang, which were produced in the setting of compressive tectonism. We compared bimodel dikes and Sanqingshan A‐type granite in the northeastern Jiangxi, and Huanshitan and other A‐type granites in the northern Zhejiang, which formed in the setting of extension. We proposed that approximately in Middle Jurassic time (175 ± 5 Ma), South China entered into the tectonic system, roughly from south to north oblique subduction of the Paleo‐Pacific Plate. The intermission period of the magmatic activities in Japan and South Korea (~170–120 Ma) was actually the period of the large‐scale magmatic‐ore forming activities in South China. Thus, this oblique subduction resulted in the dynamic imbalance and mutual movement from the deep part to the shallow part of the crust among surrounding blocks of South China and the multiple blocks of South China including those orogens between the North and South China blocks, between the Yangtze Craton and Cathayasian Block, and between the South China Block and Indosinian Block, as well as microcontinental blocks within Cathaysia Block. At present, we cannot rule out the influence of compressional–extensional tectonism for the Gan‐Hang Belt controlled by the Paleo‐Asia tectonic system.

Origin of Qinxi Silver Polymetallic Deposit in Southeast Coast, China: Evidences from H–O–S–Pb Isotopes and Mineral Rb–Sr Geochronology

“…According to metallogenic characteristics and continental dynamic background, orogeny can be divided into early, middle and late stages, accompanied by three large stages of mineralization. The first stage was characterized by mantle magma upwelling and generated a certain number of mafic rocks between 185 to 170 Ma [22,55]. It reflects the local "extensional cracking" of lithosphere and the upwelling of mantle material.…”