Geochronology, Geochemistry And Tectonic Significance Of Paleozoic And Mesozoic Granitoids In The Southern Area Of Da Hinggan Mountains, China

The ore-field of Shizishan is the richest reserves to copper-gold ore field currently at Tongling, Anhui. This area is dominated by NNE structure and NE、SN、EW structure as basic multi- tectonic of superposed structure which make all deposits in the ore field presented as steam box form. The whole passage applies basic theories and approaches of the mine field structure, and also combines the specific field geological investigation with the lab research to discuss the distribution characteristics 、 ore-controlling regularities of structure and the evolutionary episodes of tectonic stress field, which simultaneously uses both distinctions of the stratum and the magma to conclude the regularity.The passage shows that Shizizshan ore-field has typical distribution characteristics, which exists the porphyry deposit of quartz diorite bodies and the skarn deposit. Given the specific example from Dongguashan: the deepest is porphyry copper and the upper is skarn Cu deposit;the middle is interlamination skarn deposit whcih scatter the in Huashuling, Laowuling,Datuanshan and the west of Shzizishan and the skarn deposit of Hucun; the shallow part is the cryptoexplosive breccia deposit in the east of Shizishan and the skarned-overlapped-mesotherm-hydrothermal deposit and weathering-leaching deposit. The ore-field is dominated by NNE structure and NE、SN、EW structure as basic superposed structure of multi- tectonic, which is ranked separately as rock-controlling and mine-controlling and decides the rock and the pattern of space distribution. Shizishan ore field had gone through different changes of tectonic stress field 、 orientations and tectonic deformations. The comparatively intense structural distortion was fold deformation of NE-orientated in the Indosinian、EW trending in the Early Yanshanian and rotation in NNE of Yanshanian. The final deposits were the collectively formation of the magma-fluid floor-mineralize in the Yanshanian no matter where the original of metallogenic minerals from and if the mineralization mechanism or the geologic features were difference. The fractures of deposit separately provide the passages for the intrusion of magma and the reserve spaces of vein oerbodies. Additionally, bedding decollement structures which is the most the important depositing ore structure give the both passage of ore solution and storage place and also decide the multilayer mineralization. The intrusion of intermediate-acid magmatic,favorable lithohorizon and lithological association,Superimposed compounding for different orientations are the most important geological criteria,the taken place of deposits especially proceed in the different orientations in compounding of structures and the exposed rocks, which as the example of the Cishan gold field to predict.