中文摘要：

东德沟橄榄岩出露于中国新疆伊犁—中天山板块和塔里木板块之间西南天山造山带的北缘,含大量角闪石、金云母等含水矿物,显示全部遭受了不同程度的交代变质作用。岩石主量元素含量变化较大,其后期蚀变基本向富铝和富钙两个方向变化,其Nb/Ta和Zr/Hf值显示难熔地幔残余的特征。该区橄榄岩轻重稀土分馏较明显,稀土元素配分曲线总体为LREE富集的右倾型,且富集大离子亲石元素Rb、Ba、Sr和放射性元素Th,但岩石呈现不一致的解耦现象,即主量元素表现难熔而稀土元素、不相容微量元素体现富集,说明主量元素和微量元素具有各自的演化特点。研究认为东德沟橄榄岩是经历部分熔融的楔形地幔残余,微量元素呈现的特征是俯冲板块析出熔体或流体交代的结果。与其岩石矿物学研究结果一致,对东德沟橄榄岩地球化学特征的深入研究证明,它们来源于SSZ环境俯冲上板片地幔楔橄榄岩残片。

英文摘要：

The Dongdegou peridotites are located at the northern of orogenic belt between the Tarim Plate and the Yili—Central Tianshan Plate, southwestern Tianshan Mountains, China, have a lot of amphibole, phlogopite and other hydrous minerals, which shows various degrees of metamorphism. Major elements of the peridotites change in a wider range and toward Al-rich or Ca-rich tendency during the late alteration, their Nb/Ta and Zr/Hf ratios display that they have the characteristics of refractory mantle residuals. The chondrite-normalized REE patterns of the peridotites are types of LREE-enriched patterns, based on the obvious fractionation between LREE and HREE, and also enriched in LILE of Rb, Ba, Sr and the radioactive element Th. However, the major elements are refractory, when the rare earth elements or incompatible trace elements are enriched in the same samples. Thus, the decoupling phenomenon indicates the major elements and the trace elements have their own evolutionary characteristics, respectively. Therefore, the Dongdegou peridotites are the depleted wedge mantle residuals after partial melting, and the characteristics of trace elements indicate they might have been metasomatized by the melts or fluids from a subducted slab. Geochemical studies of the peridotites illustrate also that they most likely come from a SSZ Mantle wedge, just as the result from the research of their mineralogy and petrology.