摘要
实测了云南西部兰坪盆地云龙县城南沘江西岸下白垩统南新组剖面。通过野外实测资料以及岩石薄片的观察描述,综合分析了研究区南新组的岩石组合、沉积构造、剖面结构等特征,认为南新组自下而上主要为曲流河相和湖泊相,厚度较薄的土壤相常作为夹层与前两者交互出现。河流相可进一步识别划分出河道、边滩、河漫滩、天然堤等亚相;湖泊相则可分辨滨湖、浅湖、半深湖三种亚相;古土壤相可分为钙质土和潜育土两种类型。相序结构指示研究区在早白垩世南新组沉积期为一个由构造运动相对活跃到较为稳定的过程,岩相组合结合土壤相分析显示气候以亚热带干旱-半干旱为特征。
A cross-section of Lower Cretaceous Nanxin Formation was measured at west bank of Bijiang River near Yunlong county,western Lanping basin.Lithofacies and subfacies were analyzed by microfacies under microscope and observation of lithology,sedimentary structure in the field.Three lithofacies can be recognized from the Nanxin Formation：meandering river facies,lacustrine facies interbedded or intercalated with thin paleosol facies.Subsequently,the meandering river facies is subdivided into four subfacies of channel,point bar,levee and overbank;and the lacustrine facies can be subdivided into shore,shallow and semi-deep lake subfacies.The paleosol facies is classified as calcareous soil and gleysol.Lithofacies succession and association of Nanxin Formation indicate a change of relative active to stable in regional tectonics,and sub-tropic hot semi-arid and arid weather during sedimentary of Nanxin Formation in Early Cretaceous.
出处
《华南地质与矿产》
CAS
2012年第2期141-148,共8页
Geology and Mineral Resources of South China
基金
国家重大基础研究发展规划项目(973)
课题"中国白垩纪重要时期的古气候重建"(2006CB701401)
关键词
岩相
古气候
南新组
下白垩统
云南云龙县
lithofacies
paleoclimate
Nanxin Formation
Lower Cretaceous
Yunlong county,Yunnan province
