麦哲伦海山区MA、MC海山玄武岩基岩的岩石学特征  

PETROLOGY OF THE BASALT BASEMENTS IN TWO SEAMOUNTS MA AND MC OF MAGELLAN SEAMOUNTS

作　　者：朱克超[1] 李扬[1] 赵祖斌[1] 

机构地区：[1]国土资源部广州海洋地质调查局第二海洋地质调查大队,广州510760

出　　处：《海洋地质与第四纪地质》1999年第4期11-19,共9页Marine Geology & Quaternary Geology

基　　金：中国大洋协会DY95-7航次勘查项目

摘　　要：麦哲伦海山区MA、MC海山玄武岩基岩的岩石学特征研究表明，岩性为蚀变玄武岩、橄榄玄武岩等；结构为基质具间隐、间往结构及拉斑玄武结构的斑状结构；矿物组成为斜长石、橄榄石、辉石及脱玻化玻璃等。按岩石化学成分分类属碱性玄武岩，而稀土分配模式属洋岛碱性玄武岩类型。The study of the petrology of the basalt basements in two seamounts MA and MC of the Magellan seamounts indicate:(1)Basalt basements in seamounts MA and MC are altered basalt and dorgalite etc.with intersertal and intergranular texture in matrix and porphyritic texture,and in massive and vesicular structures. Mineral compositions are plagioclase,olivine,pyroxene and devitrified glass etc.(2)Bulk analysis of silicate in basalt basements indicates that the chemical compositions are very close to the average compositions of oceanic alkaline basalt,and the basalt basements should be alkaline basalt according to Si-alkali diagram of basalt classification and belong to calc-alkaline rock on the basis of composite indexes of the alkalinity.(3)Chemical analysis of RE elements of the basalt basements shows that ∑REE belongs to the range of oceanic basalt;REE distribution pattern is in alkaline basalt type and shown as LREE enrichment. Ce shows some negative anomaly or non-anomaly,in consistent with alkaline basalt in classification of silicate chemical compositions.

关 键 词：玄武岩 基岩 麦哲伦海山 岩石学 

分 类 号：P588.145[天文地球—岩石学]