青海省达卡地区三叠系巴颜喀拉山群岩石学特征及物源分析  

Petrological Characteristics and Provenance Analysis of the Trassic Bayan Har Group in Daka,Qinghai Province

作　　者：刘大明[1] 孙占营 杨鹏涛[1] 敬乐 余亮 赵学森 Liu Daming;Sun Zhanying;Yang Pengtao;Jing Le;Yu Liang;Zhao Xuesen(Northwest Sichuan Geological Party, BGEEMRSP, Mianyang Sichuan 621000, China)

机构地区：[1]四川省地质矿产勘查开发局川西北地质队,四川绵阳621000

出　　处：《地质科技情报》2018年第2期71-78,共8页Geological Science and Technology Information

基　　金：中国地质调查局项目(12120114017801)

摘　　要：通过对青海省达卡地区三叠系巴颜喀拉山群碎屑岩的岩石学特征、岩石地球化学特征进行研究,初步分析了该地区的物源。研究表明,达卡地区的三叠系巴颜喀拉山群岩石类型复杂,其复成分的砾岩、岩屑长石砂岩、岩屑石英砂岩均表现出近源沉积的特征,该区的构造背景以活动大陆为主,次为大陆岛弧区,物源性质主要为再旋回物源区造山带,少量为岩浆岛弧带,表现出物源的多样性,主体应为一套以变质酸性火山岩为主的区域。化学蚀变指数(CIA)及成分成熟度(ICV)均较低,反映出物源区可能处于半干旱-干旱气候条件的构造较活动区域。To learn the petrological and geochemical characteristics of the Triassic Bayan Hat Group sand- stone in Daka, Qinghai Province, this study preliminarily analyses the provenance. The study results show that this Triassic Group consists of complex rock types, including conglomerate, lithic feldspar sandstone and lithic quartz sandstone, with the characteristics of proximal deposition. Its tectonic setting is domina- ted by active continent, followed by continental island arc. The provenance is mainly of the recycling oro genic belt with a little from magmatic arc belt. This illustrates that the main provenance should be a pre- dominantly metamorphic acid volcanic rock area. The chemical alteration index （CIA） and compositional maturity （ICV） is lower, reflecting that the provenance may be in semi-arid--arid climate condition of tec- tonic activity area.

关 键 词：青海 达卡 巴颜喀拉山群 岩石学特征 地球化学 物源 

分 类 号：P534.51[天文地球—古生物学与地层学]