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Zou T.,Beijing Institute of Geology for Mineral Resources | Zou T.,Kunming University of Science and Technology | Wang Y.-W.,Beijing Institute of Geology for Mineral Resources | Wang Y.-W.,Kunming University of Science and Technology | And 5 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2012

A large number of mafic enclaves are widely distributed in the host porphyry of Aolunhua porphyry Mo-Cu deposit, Inner Mongolia. These mafic enclaves are mainly dioritic, elliptic in shape and are of microgranular and igneous-texture. Under microscope, the acicular apatite and eyeball-shape quartz with mafic minerals selvage are developed in the enclaves. These enclaves have captured lots of corroded and recrystallized plagioclase, quartz, biotite phenocrysts from host rock. All these characteristics indicate an obvious magma mixing genesis of the mafic enclaves. Geochemically these mafic enclaves are more basic than their host rocks, and the major oxides of the mafic enclaves and the host rocks are plotted on same a linear trend. The REE pattern, trace element and isotopic signatures of the dioritic enclaves and of the magma-mixed rocks are similar to those of the host granites, which suggest that exchanges of elements occurred between the enclaves and the host rocks. Consilient single-zircon U-Pb age of (134.1±1.4) Ma from the host rock and (133.6±1.0)Ma from the mafic enclaves also prove that the mafic enclaves is the product of magma mixing. The Sr, Nd isotopic results show that the source region of Aolunhua intrusion was a immature continental crust source. The primary magma of the mafic enclaves was more basic before its mixing with the more silicic magma and could be derived from the mantle. Discovery of magma mixing in Aolunhua porphyry deposit may be the direct evidence of mantle-derived magma underplating in the region.

Liu S.-F.,China Non Ferrous Metal Resources Geological Survey | Liu S.-F.,Chinese Academy of Science | Du Y.-S.,China University of Geosciences | Fu S.-X.,China Non Ferrous Metal Resources Geological Survey | And 2 more authors.
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences | Year: 2013

The formation of the Yaojialing Zn-Au-polymetallic deposit located in the eastern of Tongling ore deposit concentration area is closely related with the granodiorite porphyry. However, the previous studies on the rock is still less, in order to further understand the diagenesis and mineralization of the Yaojialing deposit, this paper carried the analysis of the characteristics of granodiorite porphyry and the study zircon, and shows that the granodiorite porphyry belongs to high-K calc-alkaline series with relatively higher content of SiO2(67.08%-68.57%), and it is of I-type granite(the ratios of K2O/Na2O are 0.68-1.02). The zircons display oscillatory zoning with ratios of Th/U at 0.34-1.20, which suggests they are zircons of magmatic origin. The weighted average 206Pb/238U age for the zircons is 141.0±1.7 Ma, which shows that the granodiorite porphyry was formed in early Cretaceous. Zircon εHf(t) values are -22.5 to -9.2, indicating that the magma of the granodiorite porphyry was derived from partial melting of the rock in the crust. The zircons Hf isotopic two-stage model ages are 1 639-2 620 Ma, showing the time of the differentiation of crustal rock from the mantle is Paleoproterozoic. In addition, our study finds that the crystallization temperature and the diagenetic pressure of the granodiorite porphyry are 558-739°C and 50-250 MPa respectively.

Liu Y.C.,University of Science and Technology Beijing | Liu L.S.,University of Science and Technology Beijing | Wu C.P.,University of Science and Technology Beijing | Dou J.L.,China Non Ferrous Metal Resources Geological Survey | Wang X.G.,Beijing General Research Institute of Mining And Metallurgy
Rock Fragmentation by Blasting - Proceedings of the 9th International Symposium on Rock Fragmentation by Blasting, FRAGBLAST 9 | Year: 2010

To develop a new technique utilizing explosive method to separate wood fibers during pulping, enormous efforts should be made to increase the crushing efficiency of explosion. In this paper, explosion experiments were taken to investigate the effect of blast load on wet wood chips. At the top of a closed steel vessel stuffed with wet wood chips, the embedded explosive charge was detonated. The pressure in this porous medium was measured by four piezoelectric sensors. The results show that the ruptured effect of the chips can be divided into three regions, namely, disintegrated fiber zone, fracture zone, compaction zone. The attenuation characteristics of explosion waves propagating in the medium were studied. Based on the experimental results and the introduced SHPB experiments, mechanisms of rupture are proposed to interpret the fragmentation phenomena. In conclusion, some feasible methods are recommended to achieve appropriate explosive effect. © 2010 Taylor & Francis Group.

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