Dexing area of northeast Jiangxi province is one of the large ore-concentrating areas in the Eastern Metallogenic Belt of China, which includes several large or superlarge ore deposits such as Tongchang porphyry copper deposit, Yinshan polymetallic deposit and Jinshan gold deposit. The area is geotectonically located in an important place of southeast China, therefore the study of Cu-Au mineralisation in this area is always associated with that of tectonic setting and evolution. The tectonic framework of Dexing area is the collision between Jiuling terrane in the northwest and Huaiyu terrane in the southeast along the Northeast Jiangxi Deep Fault. After this collision in late Proterozoic, the area was mainly under the intraplate tectonic evolution. The mineralisation in Dexing large Cu-Au ore-concentrating area was
closely related to the Yanshanian tectono-magmatic activities, whereas the mid-Proterozoic strata have higher concentrations of ore elements, which possibly provided ore-forming materials to the ore deposits of the area. Studies on ore-forming fluid show that different deposit has its own fluid system. The Tongchang porphyry copper deposit was predominated by magma-derived fluid in the early stage and meteoric water in the late and major ore-forming stage. The Yinshan poly-metallic deposit was mainly formed by fluid of meteoric water origin. While the ore-forming fluid of Jinshan gold deposit was mainly metamorphic water formed in the ductile shearing deformation.