地质与勘探2017，Vol.53Issue(5)：903-914,12.
东天山黄山南镁铁-超镁铁质岩体锆石U-Pb年龄及岩浆演化过程探讨
Zircon U-Pb Age and the Magma Evolution Process of the Huangshannan Mafic-Ultramafic Intrusion in the East Tianshan Mountains
摘要
Abstract
The Huangshannan mafic-ultramafic intrusion is located in the Jueluotage tectonic zone in East Tianshan Mountains, which is part of the large-scale mafic-ultramafic rock belt in this area. Zircon U-Pb isotopic dating of this intrusion yields a weighted average age of 293. 7 ± 3. 1Ma, in-dicating it was generated in the Early Permian. The m/f ratios of samples from the Huangshannan intrusion range from 4. 45 to 6. 37, implying ferric ultra-basic rock. Using the maximum Fo value of olivine, we estimate that the parental magma has a Mg# of 0. 70, showing a similar composition with primary magma and a characteristic of high-Mg tholeiitic basaltic magma. The parental magma has a low evolution degree, or it has been added by surplus olivine crystal. The ratios of Ba/La, Ba/Nb, Ba/Th, Rb/Nb, Th/Nb and Sm/Yb reveal that the source of the Huangshannan intrusion is relatively enriched lithospheric mantle which was reformed by slab-derived fluids and subducting sediment. The variation features of major elements show a crystallization differentiation process;relatively high Ba/Nb, La/Nb and low La/Ba ratios as well as the negative anomaly of Ni-Ta-( Ti) indicate that the magma of Huangshannan has likely suffered crustal contamination during its emplacement. Combining the age and the geochemical characteristics of the Huangshan-nan intrusion, we consider that this rock could represent the product of mantle magmatic evolution of early stage, having a good metallogenic potential.关键词
镁铁-超镁铁质岩体/黄山南/东天山/岩浆演化Key words
mafic-ultramafic intrusion/Huangshannan/East Tianshan mountains/magmatic evolution分类
天文与地球科学引用本文复制引用
尤敏鑫,张照伟,王亚磊,钱兵,张江伟..东天山黄山南镁铁-超镁铁质岩体锆石U-Pb年龄及岩浆演化过程探讨[J].地质与勘探,2017,53(5):903-914,12.基金项目
国土资源部公益性行业科研专项项目(编号:201511020 )、国家自然科学基金青年基金项目(编号:41602094、41603050 )和中国地质调查局"东昆仑铜镍多金属资源基地调查"二级项目(编号:DD20160013)联合资助. （编号:201511020 ）
