地质学报2017，Vol.91Issue(4)：776-791,16.
新疆东天山红石岗北铜镍矿化镁铁质岩体岩石成因及成矿潜力分析
Petrogenesis and Metallogenic Potential Analysis of Mafic Intrusion in the Hongshigangbei Ni-Cu-Sulfide Mineralization in East Tianshan, Xinjiang
摘要
Abstract
The Hongshigangbei mafic intrusion was discovered by No.704 Geological Party,Xinjiang GeologicalExploration Bureau for Nonferrous Metals in 2014.It is located in East Tianshan,and controlled by theKangguer-Huangshan ductile shear zone.The mafic intrusion is composed predominantly of diorite,hornblende gabbro and olivine gabbro,with a minor amount of sufide droplets in gabbro occasionally.Sulfide mineral assemblages are composed of pyrrhotite,pentlandite and chalcopyrite.In order toaccurately evaluate the prospecting potential of the intrusion,we investigated the zircon U-Pb chronology,mineral chemistry,geochemical and Sr-Nd isotopic characters of the intrusion.Combining with thegeophysical characteristics,we compared the Hongshigangbei intrusion with the typical Ni-Cu sulfidedeposit in East Tianshan area.The zircon U-Pb isotope age of 276.1 ± 5.4 Ma reveals that the maficintrusion was formed in Early Permian.Olivine crystals in the Hongshigangbei rocks have a narrow range(Fo=69.9～72.6) and the Ni content of 101× 10-6 ～1326× 10-6.The clinopyrexene and orthopyroxenebelong to endiopside-diopside and enstatite respectively.The values of MgO (5.95％～13.06％) and FeOTshow positive correlation,but there is negative relation between MgO and SiO2,CaO and Al2O3.All thesamples are slightly enriched in LREE and positive Eu anomaly.Trace elements show a LILE-rich andHFSE-depleted(Nb,Ta) pattern.The (87Sr/86Sr)i and εNd(t) rations range from 0.70342～0.70349 and +7.51～+8.25(t=276Ma) respectively,indicating that the source of intrusion was depleted mantle.TheSr-Nd isotope trend reveals that the parental magma of the Hongshigangbei intrusion experienced about5％ crustal contamination during upwelling.Compared with the typical Ni-Cu sulfide deposits in EastTianshan,the Eo contents and major elements contents of the Hongshigangbei intrusion are in a low andnarrow range.But they are similar in isotope age,trace elements,Sr-Nd isotopic characteristics,degree ofcrustal contamination and material.This indicates that the characteristics of magma sources,tectonicsetting,composition of parental magma and evolution process may have obvious similarity betweenHongshigangbei intrusion and Huangshandong,Huangshan deposit.On the basis of the study above,wespeculate that the deep of intrusion may exist ultramfic rocks.Geophysical data also indicate that theHongshigangbei intrusion has lower polarization rate than the typical Ni-Cu sulfide deposit in EastTianshan.But they have similarity in surface magnetic anomaly,residual gravity anomaly and resistivity.These characters show that the deep of the Hongshigangbei intrusion may exist ore-bearing ultramaficintrusion.In conclusion,we believe that the deep of Hongshigangbei intrusion has large Ni-Cu prospectingpotential.关键词
红石岗北/铜镍矿化镁铁质岩体/锆石U-Pb年龄/岩石成因/成矿潜力/东天山Key words
Northern Hongshigang/Ni-Cu mineralized mafic intrusion/zircon U-Pb dating/petrogenesis/metallogenic potential/East Tianshan引用本文复制引用
王亚磊,张照伟,陈寿波,张江伟,李侃,尤敏鑫..新疆东天山红石岗北铜镍矿化镁铁质岩体岩石成因及成矿潜力分析[J].地质学报,2017,91(4):776-791,16.基金项目
本文为国土资源部公益性行业科研专项(编号:201511020),国家自然科学基金(青年)项目(编号:41302052,41402071)和中国地质调查局地质矿产调查项目(编号:DD20160013)共同资助成果. （编号:201511020）
