| 盐津地区峨眉山玄武岩地球化学特征及成因分析 |
| |
| 引用本文： | 马健飞,沙小保,刘建清,李佑国,何利.盐津地区峨眉山玄武岩地球化学特征及成因分析[J].矿物岩石,2019,39(2):25-33. |
| |
| 作者姓名： | 马健飞 沙小保 刘建清 李佑国 何利 |
| |
| 作者单位： | 成都理工大学地球科学学院,四川成都,610059;云南省地震局地震监测中心,云南昆明,650000;中国地质调查局成都地质调查中心,四川成都,610081 |
| |
| 基金项目： | 雷波等五幅区调联测项目 |
| |
| 摘 要： | 峨眉山火成岩省东部盐津地区玄武岩的岩石地球化学分析结果表明,盐津玄武岩w(SiO2)为47.97%~52.33%,w(Na2O+K2O)为3.35%~6.57%,Ti/Y值为496.29~567.80,w(TiO2)为3.60%~4.14%,属于钙碱性高钛玄武岩(HT)。岩石LREE/HREE值为7.34~7.88,轻稀土元素富集,分馏程度高,总体亏损Ba,K,Sr,P。高场强元素Nb/U比值为26.39,Ce/Y-Sm/Y和Th/Nb-Ce/Nb等比值均呈明显正相关系,表明盐津地区峨眉山玄武岩受到了明显地壳混染作用。Nb-Nb/Y和La-La/Sm图解中样品投点呈倾斜直线,表明盐津玄武岩岩浆受分离结晶作用影响较弱,δEu值为0.86~0.93,CaO/Al2O3与Mg#无明显相关关系,以及镜下观察均表明仅有少量斜长石、单斜辉石的分离结晶。盐津玄武岩与盐源和越西等地高钛玄武岩地球化学特征相似,具地幔柱成因特征,岩浆可能起源于富集地幔。分配系数相近的强不相容元素Ce/Sm比值为25.50,La/Yb-Sm/Yb图解中样品靠近石榴石尖晶石二辉橄榄岩区域,表明岩浆源区为石榴石尖晶石二辉橄榄岩。
|
| 关 键 词： | 盐津 峨眉山玄武岩 地球化学特征 岩石成因 |
GEOCHEMICAL CHARACTERISTICS AND GENESIS OF EMEISHAN BASALT IN YANJIN AREA |
| |
| MA Jianfei,SHA Xiaobao,LIU Jianqing,LI Youguo,HE Li.GEOCHEMICAL CHARACTERISTICS AND GENESIS OF EMEISHAN BASALT IN YANJIN AREA[J].Journal of Mineralogy and Petrology,2019,39(2):25-33. |
| |
| Authors: | MA Jianfei SHA Xiaobao LIU Jianqing LI Youguo HE Li |
| |
| Institution: | (College of Geosciences,Chengdu University of Technology,Chengdu 610059,China;Earthquake Monitoring Center of Yunnan Seismological Bureau,Kunming 650000;Chengdu Center of Geological Survey,China Geological Survey,Chengdu 610081,China) |
| |
| Abstract: | Geochemical analyses on the Emeishan basalt in the Yanjin area shows that the w(SiO2) of rock is 47.97%~52.33%,w(Na2O+K2O) is 3.35%~6.57%, Ti/Y value is 496.29~567.80,w(TiO2) is 3.60%~4.14%,characteristic of calc-alkaline high-titanium basalt(HT).Light rare earth element is enriched(LREE/HREE=7.34~7.88) with high degree of fractionation and with depletion of Ba,K,Sr and P.The Nb/U ratio of high field strength element is 26.39 and the ratios of Ce/Y-Sm/Y and Th/Nb-Ce/Nb are obviously positive,hich indicates that the Emeishan basalt in Yanjin area is contaminated by crust.The plots in Nb-Nb/Y and La-La/Sm diagrams display inclined straight lines,demenstrating that the Yanjin basalt magma is weakly affected by separation and crystallization.δEu value of the basalt is in the range of 0.86~0.93 and there is no significant correlation between CaO/Al2O3 and Mg#.Microscopic observation shows that only a small amount of plagioclase,clinopyroxene display separation and crystallization.It is considered that the Yanjin basalt is similar to the high-titanium basalt in Yanyuan and Yuexi area,characteristic of mantle plume.It is likely that the magma is originated from the enriched mantle.The Ce/Sm ratio of strong incompatible elements with similar distribution coefficients is 25.50,and the sample in La/Yb-Sm/Yb diagram is close to the garnet spinel olivine peridotite region,indicating that the magma source region is probably garnet spinel olivine peridotite. |
| |
| Keywords: | Yanjin Emeishan basalt geochemical characteristics petrogenesis |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
|
