东昆仑南缘哥日卓托地区马尔争组砂岩碎屑组成、地球化学特征与物源构造环境分析  

Detrital Composition,Geochemical Characteristics and Provenance Analysis for the Maerzheng Formation Sandstone in Gerizhuotuo Area,Southern Margin of East Kunlun Region

作　　者：裴先治[1,2] 胡楠[2,3] 刘成军[2] 李瑞保[1,2] 李佐臣[1,2] 陈有炘[2] 裴磊[4] 刘战庆[5] 陈国超[2] 杨杰[2] 

机构地区：[1]西部矿产资源与地质工程教育部重点实验室,西安710054 [2]长安大学地球科学与资源学院,西安710054 [3]中煤航测遥感局遥感应用研究院,西安710054 [4]中国地质大学(北京)地球科学与资源学院,北京100083 [5]桂林理工大学地球科学学院,广西桂林541004

出　　处：《地质论评》2015年第2期307-323,共17页Geological Review

基　　金：国家自然科学基金项目(编号41172186;41472191;40972136);高等学校博士学科点专项科研基金项目(编号20110205110004);中央高校基本科研业务费专项资金项目(编号CHD2011TD020;2013G1271091;2013G1271092);青海省国土资源厅-中国铝业公司公益性区域地质矿产调查基金项目(编号:中铝基金200801)的成果

摘　　要：出露于东昆仑南缘布青山构造混杂岩带内的马尔争组沉积地层,其主体为一套沉积于被动大陆边缘构造环境的大陆斜坡相深海—半深海浊积岩.利用砂岩碎屑组分统计分析及岩石地球化学特征研究,探讨物源区源岩类型及其构造环境.砂岩骨架成分统计表明马尔争组砂岩主要类型为长石岩屑砂岩且成熟度较低,砂岩碎屑骨架成分为石英、长石、岩屑,含量平均值分别为44％、21％、35％,Dickinson三角图解显示其物源类型为再旋回造山带物源区和岩浆弧物源区的混合物源.砂岩岩石地球化学特征结果显示,马尔争组砂岩样品SiO2=58.12％～72.98％,均值67.77％,REE配分曲线总体表现为右倾,∑LREE/∑HREE =6.5～12.1,δEu =0.63～0.75,Eu具弱负异常,CIA值为56说明源岩遭受初级强度风化作用,具近源沉积特征.研究结果指示马尔争组砂岩物源区构造环境为大陆岛弧,源岩性质为长英质火山岩和花岗岩类源岩且主要来源于北侧东昆仑造山带加里东期岩浆弧与变质基底,沉积盆地类型为深海—半深海盆地.它是古特提斯洋北支布青山—阿尼玛卿洋演化历史过程中一次重要的沉积响应.The sedimentary stratum of Maerzheng Formation is exposed in the Buqingshan Melanges Belt of Southern margin of the East Kunlun region, and it＇ s main part is a set of turbidite of deposition in tectonic setting of passive continental margin of bathyal--abyssal environment. Using analysis of sandstone compositions and geochemical characteristics to explore provenance source rock type and its tectonic setting. The framework composition of the Maerzheng Formation sandstones statistical results show that it＇ s mainly feldspathic litharenite and lower maturity, it＇ s quartz, lithic, feldspar respectively is 44%, 21%, 37 %, the Dickinson diagrams show that provenance is mainly divided from orogenic belt and recycled island arc in category. The geochemical characteristics of sandstones of Maerzheng Formation show that SiO2 values of 58.12% -72.98%, average value of 67.77% , the REE distributing patterns show rightward incline and weaker negative Eu anomaly, ∑ LREE/∑ HREE = 6.5 - 12. 1, δEu = 0.63 -0.75, the CIA average value of 56 indicates that source rock by primary weathering intensity and have the near source sedimentary characteristics. The results indicate that tectonic setting belong to continental island arc type, the provenance is the volcanie--plutonic magmatic island arc orogene and metamorphic basement of northern East Kunlun block, the sedimentary basin is the trench basin. Consequently, its the important sedimentary response of evolution process of A＇ nyemaqen--Buqingshan Ocean.

关 键 词：东昆仑南缘 马尔争组 浊积岩 砂岩骨架成分 砂岩地球化学 大陆岛弧 

分 类 号：P588.21[天文地球—岩石学]