摘要
湘南地区四组中生代橄榄岩包体单斜辉石（cpx）Nd同位素分析结果表明橄榄岩包体具极为亏损的Nd同位素组成（147Sm／144Nd=0．1825～0．2676．143Nd／144Nd=0．513401～0．513667）。其中前三组样品的lDM年龄分别为2．19，1．44和1．83Ga，另一样品93Ti-18则受到后期改造且发生了LREE富集作用。结合橄榄岩包体的岩石化学矿物化学特征，可以认为橄榄岩为本区早期地壳增生过程中漫源岩浆的堆晶体。
The Nd isotopic compositions of four clinopyroxenes separated from spinel lherzolitexenoliths in Mesozoic basalts from Ningyuan, South Hunan, are reported. It is indicated that thelherzolite xenoliths are fairly depleted in Nd isotopes with high 143 Nd/144 Nd ratios (0. 513 4010. 513 667). Three xenoliths have depleted mantle model ages (tDM) of 2. 19 Ga, 1. 44 Ga and1. 83Ga, respectively. Another sample 93Ti-18, which is less depleted in Nd isotopic composition.had undergone late alteration and LREE-enriching processes. Combining with the dala from petrochemlstry and mineral chemlstry of the xenoliths, the authors believe that the lherzolite xenolithswere derived from the early crystal fractionation of mantle-derived magmas during the ancientcrustal growth from the Early to Mlddle Proterizoic.
出处
《矿物学报》
CAS
CSCD
北大核心
1999年第2期206-209,共4页
Acta Mineralogica Sinica
基金
国家自然科学基金!492520001
中国科学院院长基金
关键词
橄榄岩包体
同位素组成
岩石成因
钕同位素
peridotite xenolith
Nd isotopic composition
petrogenesis
Mesozoic
South Hunan
