Magma Mixing Origin Of Yamatu Granite In Nuoergong-Langshan Area,Western Margin Of North China Craton: In-situ Zircon U-Pb，hafnium Isotopic，Petrology And Geochemistry Evidences

The Yamatu pluton in Nuoergong-Langshan area is located in the western marginof the North China Craton. It consists mainly of monzogranite with many dioritic andgabbro enclaves. These enclaves have plastic shape and magmatic structure,quenchboundary,back-up veins and unbalanced textures,such as acicular apatite,quartzocellar texture and plagioclase zoning. The monzogranites belong to high-Kcalc-alkaline to transitional series.Geochemically,SiO₂of the enclave samples varyfrom48.40%to55.40%,and the contents of Fe,Mg,Ca and Ti in the enclave samplesare higher than those of their host granites. The enclaves and their host granites havesimilar characteristic of major and trace elements,and show good linear relationship inHarker diagrams of the enclaves and their host granites.These characteristics suggestthat there should be obvious genetic relationship between the enclaves and their hostgranites. The TFeO-MgO diagram of the enclaves and their host granite shows a veryclear trend of magma mixing. Zircon LA-ICPMS dating from the grabbro enclaves is270±1Ma，which is consistent with the age of host granite. The εHf（t） values ofgrabbro enclaves range from-13.29to-6.86, εNd（t） values vary from-9.1to-8.8, andinitial⁸⁷Sr/⁸⁶Sr （ISr） are0.70686to0.70682. And the εNd（t） values of host granies varyfrom-12.5to-10.4, and initial⁸⁷Sr/⁸⁶Sr （ISr） are0.70747to0.7077.These featuressuggest that the source characteristics of enclaves and host granites are different. Theenclaves from the Yamatu pluton are probbaly derived from quenching of maficmagma into felsic magma.Based on our studies and previous results, plutons in Nuoergong-Langshan areaaging mainly in the Permian（275Ma）.In a late-collision stage related to a significantchange in regional tectonic framework from collision-related compression toextension. Because crustal stretching the thinning of the curtain rose source materials,leading to the bottom of the magma invasion, the jet or fountain of magma forms intolong of the magma, because both the temperature of the magma, viscosity andinjection rate and other factors, there was a different level of magma mixing action.The Permian Nuoergong-Langshan area of magma and long of the magma mixing effect, make a number of active high magma fluid dissolved out in theneighborhood and some Cu deposit metallogenic role-Au has important contribution,for ZhuLaZhaGa gold provide after-sales hydrothermal ore-forming.