岩石矿物学杂志2025，Vol.44Issue(6)：1325-1339,15.DOI:10.20086/j.cnki.yskw.2025.5036
桂北新元古代OIB型辉长岩年代学、岩石地球化学特征及岩石成因研究
Geochronology and geochemical of the Neoproterozoic OIB-like gabbro from North Guangxi and constraint on its petrogenesis
摘要
Abstract
We reported zircon SIMS U-Pb ages,the whole rock geochemistry of the Shuanglang gabbro located in Longsheng County,North Guangxi from the western Jiangnan Orogen in this manuscript,to decipher their petrogen-esis and tectonic setting.Samples comprised clinopyroxene and plagioclase with minor K-feldspar and Fe-Ti oxides.The Shuanglang gabbro with a zircon SIMS U-Pb age of 782±9 Ma.The bulk-rock have SiO2(50.05％～51.85％),Al2O3(14.53％～15.42％)and CaO(6.95％～7.19％)contents,and MgO(8.97％～11.33％)and total FeO(10.63％～11.92％)contents.The samples display ocean island basalt(OIB)-like geochemical signatures,with the enrichment of light rare earth elements(LREE)and large-ion lithophile elements(LILE)relative to heavy rare earth elements(HREE),with insignificantly negative Nb,Ta anomalies,and have high(87Sr/86Sr)i(0.709 990～0.711 788)and negative εNd(t)(-2.4～-1.4)values resulted from the upper crust contamination.They are sug-gested to have originated from a small degree(3％～4％)of partial melting of the upwelling asthenospheric man-tle in an extensional setting of the garnet stability field.Based on the spatial distribution of the mafic-ultramafic rocks during 780～750 Ma in the western Jiangnan Orogen reported in both this study and previous publications and comprehensive analyses of them,we indicate that the subducted slab break-off triggered the partial melting of up-welling asthenosphere,which resulted into the formation of the OIB-like mafic-ultramafic rocks during 780～750 Ma in the western Jiangnan Orogen.关键词
锆石SIMS U-Pb年龄/双朗辉长岩/岩石成因/构造背景/软流圈上涌Key words
zircon SIMS U-Pb age/Shuanglang gabbro/petrogenesis/tectonic setting/upwelling of the astheno-sphere分类
天文与地球科学引用本文复制引用
寇彩化,刘燕学,丁孝忠,靳胜凯..桂北新元古代OIB型辉长岩年代学、岩石地球化学特征及岩石成因研究[J].岩石矿物学杂志,2025,44(6):1325-1339,15.基金项目
深地国家科技重大专项青年课题(2024ZD1001208) （2024ZD1001208）
国家自然科学基金面上项目(41972069) （41972069）
中国地质调查项目(DD20221645,DD20221648) National Major Science and Technology Project on Deep Earth(2024ZD1001208) （DD20221645,DD20221648）
National Natu-ral Science Foundation of China(41972069) （41972069）
China Geological Survey(DD20221645,DD20221648) （DD20221645,DD20221648）
