摘要
西藏日喀则地区蛇绿岩中地幔方辉橄榄岩铂族元素总量 (w (∑PGE) =( 2 8 37～ 50 67)× 1 0 - 9)比原始地幔和世界范围内一些典型蛇绿岩中地幔橄榄岩及阿尔卑斯型地幔橄榄岩偏高 ,相对原始地幔富集Pt,Pd ,Ru ,Ir;其PGE分布型式为“正倾斜型”或“燕子型” ,与部分熔融残留成因地幔橄榄岩中通常所观察到的负斜率型或平坦型不同 ,暗示本区残留地幔方辉橄榄岩除经历了地幔部分熔融过程外 ,很可能还经历了具高度不相容组分的熔体 /流体的渗透混合过程———地幔交代。
The harzburgites from Xigaze ophiolites in Tibet are relicts of the partial melting upper mantle. The total w (PGE) amounts of them are (28 37～50 67)×10 -9 , slightly higher than those of mantle peridotites in the primitive mantle, and typical ophiolites in the world, and the Alps-type mantle peridotites. They have relatively high total w (PGE) amounts and are enriched in Pt, Pd, Ru, Ir to Primitive Mantle. Their PGE distribution patterns belong to the positively inclined- or swallow-type patterns different from those of the mantle peridotites of partial melting relict origin. Relative enrichment in Pt and Pd, as well as in the incompatible elements such as Cu, Au, Cs, Rb, Ba, Th, U and LREE, and U-type REE patterns, indicates that the partial melting-derived relict harzburgits from Xigaze ophiolites have experienced intensive permeating and mixing processes of the melt and fluid both containing abundant incompatible elements.
出处
《桂林工学院学报》
2001年第1期42-47,共6页
Journal of Guilin University of Technology
基金
国家自然科学基金!项目 (4 9772 10 9)
国家科技部"国家重点基础研究发展规划"九七三项目! (G19990 432 0 4)
国家攀登预选项目!
