岩石矿物学杂志2025，Vol.44Issue(5)：1092-1116,25.DOI:10.20086/j.cnki.yskw.2025.4180
东昆仑希望沟镁铁-超镁铁质杂岩体角闪石特征及其标识意义
The mineralogy of amphibole and its indicative significances in Xiwanggou mafic-ultramafic complex,East Kunlun
摘要
Abstract
The Xiwanggou mafic-ultramafic complex is located in the eastern segment of the Central Kunlun Zone and the magma differentiation is sufficient with lithologies consisting of gabbro facies,pyroxenite facies,and perido-tite facies.Amphibole preserves crucial information regarding magmatic evolution and the geological setting of its formation,and it is ubiquitously present across diverse lithologies within Xiwanggou complex.In this study,we use the characteristics of major and trace elements contents in amphiboles,in conjunction with whole-rock geochemistry and the major element characteristics of plagioclases,to discuss the petrogenesis and magmatic evolution of the complex.The findings offer novel constraints on the tectonic evolution of the East Kunlun spanning from the Late Paleozoic to the Early Mesozoic.Experimental results demonstrate that all the amphiboles are mainly classified as pargasite and Mg-hastingsite of magmatic origin,bearing the typical hallmarks of subduction amphiboles.Calcula-tions indicate that the crystallization at the range of 889～971 ℃,191～280 MPa,△NNO+O.2～+1.8,and the magma water content is 2.8％～4.6％.From these results,it can be inferred that during the magma evolution,it underwent the process of cooling,decompression,reduction,and water enrichment.The compositions of amphibole melt at equilibria display highly comparable trace element and rare earth element signatures.Major element con-tents reveal that the melt compositions associated with amphibole crystallization in pyroxene peridotite,olivine py-roxenite,and gabbro are relatively primitive,while the melts during amphibole crystallization in amphibole gabbro exhibit relatively evolved characteristics.Comprehensive analysis indicates that the diverse rocks within the Xiwang-gou complex were formed during different evolution stages of homologous magma.As the magma ascended and em-placed,it progressively evolved,becoming enriched in Si and depleted in Mg,and underwent the fractional crystal-lization of plagioclase.These rocks thus serve as critical magmatic records,documenting the subduction of the Paleo-Tethys Ocean beneath the East Kunlun Orogen during the Early-Middle Triassic period.关键词
镁铁-超镁铁质杂岩体/角闪石/岩浆过程/东昆仑Key words
mafic-ultramafic complex/amphibole/magmatic process/East Kunlun分类
天文与地球科学引用本文复制引用
钟嫔彦,赵志雄,吕书俊,董国臣,朱弟成,梁景利..东昆仑希望沟镁铁-超镁铁质杂岩体角闪石特征及其标识意义[J].岩石矿物学杂志,2025,44(5):1092-1116,25.基金项目
国家自然科学基金项目(42121002,42330307) National Natural Science Foundation of China(42121002,42330307) （42121002,42330307）
