峨眉山中三叠统绿豆岩特征及其沉积环境指示  

Characteristics of the Middle Triassic Mung Beans Rock in the Mount Emei Area and their Implications for Sedimentary Environment

作　　者：芦云飞 孟万斌[1,2] 冯明石 张春光[1] 王峻 王潇 张叶[3] LU Yun-fei;MENG Wan-bin;FENG Ming-shi;ZHANG Chun-guang;WANG Jun;WANG Xiao;ZHANG Ye(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610059,China;College of Energy Resources,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]油气藏地质及开发工程国家重点实验室,成都610059 [3]成都理工大学能源学院,成都610059

出　　处：《矿物岩石地球化学通报》2020年第3期626-636,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金青年科学基金项目(41702111)。

摘　　要：为探讨峨眉山中三叠统绿豆岩的岩石学分类及其对沉积环境的指示意义,通过岩石薄片鉴定、扫描电镜观察、能谱分析及全岩地球化学分析确定了绿豆岩的岩矿特征与地球化学特征。结果表明,绿豆岩矿物成分主要为伊利石、玉髓、方解石;根据其成因与岩矿特征将其定名为含硅质颗粒伊利石黏土岩,并根据火山碎屑岩分类方案将其归入火山碎屑沉积岩类;地球化学分析表明,绿豆岩具有富钾、钠、锂,轻稀土相对富集,Eu显著亏损、Ce相对富集的特征;指示了绿豆岩沉积时峨眉山地区以炎热干旱型气候为主,水体为微咸水-咸水、亚氧化-亚还原状态。In order to explore the petrological classification and the significance to sedimentary environment of the Middle Triassic mung bean rock in the Mount Emei area,the petrographic and geochemical characteristics of the“mung bean rock”have been studied by using microscopic identification of thin section,SEM observation,EDS analysis and bulk rock geochemical analysis.The results show that the main mineral components of the“mung bean rock”are illite,chalcedony,and calcite.Based on its genetic and petrographic characteristics,it is named as"siliceous grain-bearing illite clay rock"and is classified into"pyroclastic sedimentary rock"according to the classification scheme of pyroclastic rocks.Geochemical analyses show that it is rich in potassium,sodium,and lithium,with characteristics of relatively enriched LREE,significantly negative Eu anomaly but relatively positive Ce anomaly,indicating that it was deposited in a mainly brackish-saline,sub oxidation-sub reduction water system under the hot and arid climate in the Mount Emei area.

关 键 词：绿豆岩 岩矿特征 地球化学 沉积环境 峨眉山地区 

分 类 号：P588.121[天文地球—岩石学]