滇东北会泽地区南华系沉积相与古气候特征——来自元素地球化学的证据  

SEDIMENTARY FACIES AND PALEOCLIMATE OF NANHUA SYSTEM IN HUIZE AREA,NORTHEASTERN YUNNAN PROVINCE:Evidence from Element Geochemistry

作　　者：王浩宇 张亚 徐杰 向经纬 WANG hao-yu;ZHANG Ya;XU jie;XIANG Jing-wei(Kunming Natural Resources Comprehensive Survey Center,CGS,Kunming 650000,China)

机构地区：[1]中国地质调查局昆明自然资源综合调查中心,云南昆明650000

出　　处：《地质与资源》2024年第5期626-635,661,共11页Geology and Resources

基　　金：中国地质调查局基础地质调查项目"滇中楚雄地区土地质量地球化学调查"(ZD20220210).

摘　　要：通过资料收集、剖面测制、岩矿鉴定、主微量元素分析、特征指数参数对比、沉积相综合建模等一系列工作,对滇东北会泽地区南华系沉积环境和古气候进行了探讨.该区南华系自下而上出露澄江组和南沱组,二者均为陆源碎屑岩系,呈平行不整合接触.澄江组主要包括粉砂质泥岩、粉砂岩、细砂岩、细粒石英杂砂岩和岩屑砂岩等.南沱组主要为一套灰黄色中层状复成分冰碛砾岩.澄江组中沉积旋回发育,可见小型槽状交错层理、斜层理、平行层理、水平层理等沉积构造.对澄江组细碎屑岩样品的主微量元素特征指数SD、CV、CIA、CIW、PIA、ICV、Na/K、Al/Ca、Ru/Sr、V/Cr、U/Th、Ni/Co等进行分析,其结果均指示氧化、弱氧化的沉积环境.研究认为澄江组为湖泊相,包括滨湖亚相和浅湖亚相,为温暖湿润气候类型;南沱组为冰川相,包括冰碛亚相和冰湖亚相,为寒冷干燥气候类型.The sedimentary environment and paleoclimate of Chengjiang Formation and Nantuo Formation of Nanhua System in Huize area of northeast Yunnan Province are studied through data collection,section survey,rock-mineral identification,major and trace elements analysis,correlation of characteristic index parameters and comprehensive modeling of sedimentary facies.The Chengjiang Formation and Nantuo Formation,occurred from bottom to top,both belong to terrigenous clastic rock series,showing a parallel unconformity contact.The Chengjiang Formation consists of mainly silty mudstone,siltstone,fine sandstone,fine-grained quartz gritstone and lithic sandstone.The Nantuo Formation is mainly a set of grayish yellow medium-thick polymictic moraine conglomerate.Sedimentary cycles are developed in Chengjiang Formation,with sedimentary structures such as small trough cross-bedding,oblique bedding,parallel bedding and horizontal bedding.The analysis results of major and trace element characteristic indexes including SD,CV,CIA,CIW,PIA,ICV,Na/K,Al/Ca,Ru/Sr,V/Cr,U/Th and Ni/Co of fine clastic rocks from Chengjiang Formation all indicate the sedimentary environment of oxidation or weak oxidation.It is considered that Chengjiang Formation is of lake facies,including shore-lake and shallow-lake subfacies,with a warm and humid climate;while Nantuo Formation is glacial facies,including moraine and glacial lake subfacies,with a cold and dry climate.

关 键 词：南华系 澄江组 南沱组 沉积相 古气候 云南省 

分 类 号：P532[天文地球—古生物学与地层学] P595[天文地球—地质学]