岩矿测试2017，Vol.36Issue(3)：318-325,8.DOI:10.15898/j.cnki.11-2131/td.201704060051
西准噶尔谢米斯台山西北段中志留世火山岩地球化学与Sr-Nd-Os同位素特征及其地质意义
Geochemical and Sr-Nd-Os Isotopic Characteristics of Middle Silurian Volcanic Rocks in Northwest of the Xiemisitai Mountains, West Junggar and Its Tectonic Implications
摘要
Abstract
Volcanic rocks in the Xiemisitai Mountains,in Northwest Junggar were recently considered to form in the Silurian rather than the Devonian period.However,the characteristic and tectonic setting of Middle Silurian volcanic rocks in this area are poorly constrained.In this study,major and trace elements and Sr-Nd-Os isotopic composition analyses were synthetically conducted on the Middle Silurian basalt and basaltic andesite in northwest of the Xiemisitai Mountains,West Junggar.These volcanic samples are characterized by high MgO (5.15 ％-7.81％) with Mg of 56.0-60.7,low CaO (4.56％-5.09％) and FeOT/MgO (1.15-1.40),similar to those of high-Mg volcanic rocks.Basahs have εNd(t) of 2.65,(87Sr/86 Sr) of 0.70439,and (187Os/188Os)i of 0.4901.The slightly enriched isotopic signatures,high Th/Yb (2.2-2.7) and low Ba/La (17.4-33.4) indicate that they originated from depleted mantle metasomatized by melts from subducted sediments and suffered from crustal contamination.The volcanic rocks are calc-alkaline and exhibit arc-like geochemistry with the enrichment of light REE and large ion lith ophile elements.It is suggested that these rocks were probably formed in a back-arc setting due to northward subduction of the Junggar Oceanic slab.关键词
中志留世/火山岩/Sr-Nd-Os同位素/弧后/西准噶尔Key words
Middle Silurian/volcanic rocks/Sr-Nd-Os isotopes/back-arc/West Junggar分类
天文与地球科学引用本文复制引用
陈家富,马旭,李超,屈文俊,都厚远,赵然,韩宝福..西准噶尔谢米斯台山西北段中志留世火山岩地球化学与Sr-Nd-Os同位素特征及其地质意义[J].岩矿测试,2017,36(3):318-325,8.基金项目
国家自然科学基金资助项目(41202161,41672217) （41202161,41672217）
中央高校基本科研业务费项目(N140104003,N140104004) （N140104003,N140104004）
