| Tamu ore-field is an important Pb-Zn-Cu mining area of West Kunlun metallogenic belt, most predecessors thought that its mineralization type is sedimentation-reformation or MVT, but the transforming metallogenic dynamics and hydro-thermal convection mechanism is still not clear. Based on the research on lead and zinc (copper) metallogenic regularity, this article started from the study on petrology, petrochemistry, geochemistry and its relationship with mineralization of a large number of mafic dikes recent discovered in the ore-field. It is thought that the Tamu ore-field belongs to MVT type and the hydro-thermal convection-transforming metallogenic dynamics originate from the Yanshanian period mafic magma intrusion, the copper and cobalt metallogenic materials are related to mafic intrusive rocks. The following understandings have been obtained:1) Above2340, the tendency of the main orebody I of Tamu deposit is SW, from2340to2300, the strike of the orebody appeared counterclockwise rotation, the tendency is nearly vertical, from2300to2270, horizontal direction of the orebody continued to rotate counterclockwise, the tendency transformed to NE, which is probably related to deep concealed mafic intrusions;2)ω(SiO2) of dykes is43.86×10-2～47.24×10-2, the mean is45.7×10-2.EE is172.57×10-6～244.79×10-6,δEu is0.81～0.93,δCe is0.83～0.87, A.R is1.1～1.51, DI is15.6～36.67, FL is16.65～36.58, MF is69.54～83.35, the dyke is gabbro-diabase-pyroxenite, and has LREE enrichment characters, Eu is negative anomalous, which indicate that the olivine, pyroxene and feldspar ect. Crystallize continuously or be residual in the source area in the process of magma evolution. The diagrams of Ti-Zr,(FeO)-MgO-Al2O3, K2O-TiO2-MgO, and FrF2display the magma is originated from plate interiors synthetically, which may be associated with large magmatic activities in tarim;3)The Pb isotopic composition of dykes206Pb/204Pb is17.993-18.396,207Pb/204Pb is15.598～15.65,208Pb/204Pb is38.187～38.493, which is similar to the ores and surrounding rocks. The ore lead mainly comes from the upper crust, but part has the features of mantle-derived lead, it should come from dikes;834S%o of dikes is-2.6～1.2,δ34S‰of ores is-29.3～3.9, which has the characteristics of biological reduction genesis sulfur, but may be mixed with some magmatic sulfur;4) Comprehensive study find the metallogenic type of deposit within the orefield is MVT type, but be reformed by the hydrothermal convection of mafic magma intrusion-transforming metallogenic dynamics, and the magma intrusion provides part lead, cobalt and copper metallogenic materials;5) In the deep of Tamu orefield, especially of the outcropped area of the east dike, large concealed rock mass may exist; and the deep prospecting prospect is vast. In addition to the lead-zinc mine, on the periphery of dikes (rock mass) and the contact zone, it is likely to find a vein type and skarn type copper polymetallic ore body, and finding V-Ti magnetite and Cu-Ni sulfide ore bodies at the footwall or the bottom of the dikes (rock mass) is also possible. |
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