| Abstract: | The formation, development and evolution of the Qinling orogenic belt can be divided into three stages: (1) formation and development of Precambrian basement in the Late Archaean- Palaeoproterozoic (3.0- 1.6 Ga), (2) plate evolution (0.8- 0.2 Ga), and (3) intracontinental orogeny and tectonic evolution in the Mesozoic. The Devonian (D) and Triassic (T) were the key transition period of the tectonic evolution of the Qinling orogenic belt. That is to say, in the Devonian, the Qinling micro-plate was separated from the northern margin of the Yangtze plate (passive continental margin). This period witnessed transition of the micro-plate from the compressional to extensional state, and consequently three types of sedimentary basins were formed, namely, the rift hydrothermal basin in the micro-plate, restricted ocean basin in the south, and residual ocean basin resulting from collision on the northern margin. In the Triassic the Qinling area was turned into the intracontinental orogen.The Devonian and Triassic were the main periods of enrichment of large amounts of metals. In the Devonian, many sedex-type massive Pb-Zn- (Cu)-Ag deposits were formed in the hydrothermal basins. In the Triassic (Indosinian-Yanshanian movements), many sediment-hosted disseminated gold deposits and reworked sedimentary type Pb-Zn-Hg-Sb (Au) deposits were formed in the rift hydrothermal basins. Many ductile shear zone-related gold deposits were formed in the restricted ocean basins and residual ocean basins on the two sides of the Qinling micro-plate. The above-mentioned discussion indicates that metallogenesis is not only consistent with geological events, but also controlled by them. |
