Characteristics and Spatial-Temporal Regularity of Mineral Deposits in Qinhang (or Shihang) Metallogenic Belt, South China
Institute of Mineral and Resources
CHEN Maohong, YUAN Shunda, GUO Chunli
Abstract:The Qinhang belt is located along the Qinhang (Qinzhou Bay to Hangzhou Bay) or Shihang Shiwandashan Mt. to Hangzhou Bay) Neoproterozoic suture in South China, which separates the Yangtze craton and Cathaysian Block. The most ore deposits in the belt are Mesozoic age although they occurred along the Precambrian suture. Based on the previous researches we recognize these deposits in two episodes, i.e. Neoproterozoic marine exhalative Cu-Zn deposits, and Yanshanian granitoids – related W-Sn-Cu-Pb-Zn deposits. The latter can be subdivided in Mid-Late Juarassic porphyry-skarn-vein polymetallic copper deposits, Late Jurassic granite – related W-Sn deposits, and Cretaceous epithermal Au-Ag-Pb-Zn-Sn deposits. After descriptions of the basic characteristics, ore-forming mechanics, spatial-temporal distribution of these deposits it is proposed that the Neoproterozoic marine exhalative Cu-Zn deposits occurred in the foreland basins of the oceanic islands whereas the Mid-Late Juarassic porphyry-skarn-vein polymetallic copper deposits are related the high-K calc-alkaline granites derived locally from the remelt of the subducted Izanagi plate at 180-160 Ma along the ancient Precambrian suture. The large-scale Late Jurassic granite – related W-Sn deposits associated with the crust-source granites with input of the mantle substances at 160-150 Ma, which are inferred to be the result from subducted plate window in the central part in South China and bounded in west by the Qinhang suture, where a lot of large and supper large tin and tungsten deposits developed. After 135Ma the subducted oceanic plate changed its motion direction to be along northeast, paralleling the Eurasian continental margin, which induced the large-scale lithospheric extension. Therefore, the all Cretaceous epithermal Au-Ag-Pb-Zn-Sn deposits developed within the volcanic basins and faulting basins at 120-90 Ma along the Eurasian continental margin.