西准噶尔玛依勒蛇绿混杂岩中硅质岩的岩石化学特征及其成因  

Geochemical Characteristics and Genesis of Cherts from Mayile Ophiolitic Mélange in West Junggar,Northern Xinjiang

作　　者：张丽敏[1] 李永军[1] 向坤鹏[1] 孙羽[1] 王军年[2] 杨高学[1] 

机构地区：[1]长安大学地球科学与资源学院,西部矿产资源与地质工程教育部重点实验室,陕西西安710054 [2]新疆地质矿产勘查开发局地质七队,新疆乌苏833000

出　　处：《西北地质》2014年第1期61-70,共10页Northwestern Geology

基　　金：国家自然科学基金项目(41273033);中国地质调查局项目地质矿产调查项目(基[2010]矿评01-01-05)资助

摘　　要：新疆玛依勒早古生代硅质岩一般产于蛇绿混杂岩带中,为探讨其成因类型和沉积环境,对其进行了岩相学和地球化学研究。硅质岩主要为紫红色,主要由微晶自生石英和隐晶质组成。地球化学分析结果显示样品均受到了酸性火山凝灰质的影响,一般具有高SiO2、Al2O3,低Fe2O3,中等高TiO2等特征,可能是火山和生物化学共同作用的产物。综合其地质产状、岩相学特征以及上述地球化学特征,认为该区硅质岩产于俯冲带之上的构造环境而非大洋环境。Mayile cherts of early Paleozoic generally occurred in ophiolitic mélange. Their provenance and sedimentary environment are discussed based on the petrography and geochemistry of the silicolites in the cross section of the Mayile ophiolites. The cherts are mainly purple and composed of microcrystalline authigenic quartz and implicit eutectics. According to geochemical characteristics, the samples are all influenced by the acidic volcano tuff and are probably the product of both the biochemical and volcanic process. Cherts of this type generally have higher SiO2, Al2O3 content, lower Fe2O3 content, and intermediate TiO2 content. Integrating the geological occurrence, petrography and the geochemical characteristics of those cherts, it is believed that the cherts are formed in a tectonic setting above the subduction zone rather than an open oceanic environment.

关 键 词：硅质岩 地球化学 俯冲带之上 玛依勒 西准噶尔 

分 类 号：P591[天文地球—地球化学]