Study On The Metallogenic System And Prognosis Of Cu-Mo Polymetal Deposit In The Pucheng-Ningde Metallogenic Belt Of Fujian

With the theory of metallogenic system as a guide and the application of regional metallogenic study method, this research are thoroughly carried out in the aspects of the tectonnic setting of the NW-strenching Pucheng-Ningde metallogenic belt, its ore controls, main types of ore deposits and the gennesis of each type, as well as the metallogenic regularities and prospecting direction. Through the work of the past three years, the main accomplishments obtained are as follows:1. multipe scale and multiplicity of ore controlling structure. Deep structure in the mantle concave or convex edge of mantle, Moho-discontinuity isobath (steep gradient) or local turning control the regional metallogenic belt in distribution; major fault zones and their recombination region control the metallogenic zone; great fault depression, that is, overall depression in the context of uplift, that is, or local uplift in the background of overall fault depression, or the local stronger depression in the background of overall fault depression, all of these special structures are often the enriched areas of ore-forming elements and potential prospects. Different levels of volcanic and intrusive structure control the orefields, ore deposits and orebodies, respectively.2. The main ore deposits within the belt can be divided into two metallogenic syetems :â‘ .Neoproterozoic submarine volcano-sedimentary metamorphic transformation m.s.( of copper, lead and zinc, iron, gold deposits) andâ‘¡. molybdenum, copper, lead-zinc, gold and silver deposits related to Mesozoic volcanic-intrusive hydrothermal m.s. The massive sulphide, lead-zinc, iron, copper deposits of the former and the porphyry copper-molybdenum deposits of the latter are the main ore types in the region.3. The conclusions drawn through the research on the Re-Os isotopic geochronology of the Chilu Mo deposit are as follows: (1) the model age of the Chilu Mo ore deposit is 105.6Ma, closely to the 87Sr/86S isochrone age of the porphyric granite, adamellite. So they are closely correlated in the genesis, and both are the production of magmatic evolution of the late Yanshan. (2) In the Chilu Mo deposit, the Re and Os content and the initial value of 87Sr/86S are on the low side, and the sulfur isotope is close to that of meteorite, indicating that the ore-forming substance comes from deep crust and the type is porphyry Mo deposit.4. The research on Xiashan leac-zinc deposit in Zhenghe, combining the ore-controlling characteristics of Mamianshan group in the ore concentration area of the belt. The results are as follows: (1) Neoproterozoic Mamianshan group is important ore-bearing horizon of massive sulphide lead-zinc, and copper deposit. Although undergoing the superimposed reconstruction of the structure and fluid, its stratabound characteristics still show clear. The mineralization occurred in Neoproterozoic. (2)From the current research results, the copper, lead-zinc, iron deposits are mainly controlled by greenschist and marble and other kinds of calcareous and siliceous rock. (3) the outcrop area of the Mamiansha group and its circumference in the belt has the potential of prospecting large-sized submarine volcano-sedimentary metamorphic transformation deposit.5. According to ore-forming geological setting, ore-controlling factors and the ore prospecting indicators on the main types of the ore deposits, combining the geological, geophysical and geochemical data and the heavy mineral anomalies, five metallogenic prospecting areas, six preliminary exploration areas and seven reconnaissance areas are sifted for the further ore-prospecting.