摘要
早寒武世晚期四川盆地构造背景为"两隆夹一凹"的格局,气候干旱炎热,为膏盐岩的发育创造了有利条件。通过野外剖面、钻井剖面、岩石薄片及区域地质调查等资料,总结了下寒武统膏盐岩发育特征。基于岩性特征、岩性组合方式及分区的不同,对水动力特征、沉积构造、膏盐岩单层厚度、发育规模及位置等方面的差异进行对比,结合岩相古地理研究,建立了四川盆地下寒武统膏盐岩沉积模式。研究结果表明:1)膏盐岩主要以含膏白云岩类和石膏岩类为主,膏盐岩厚度介于0.74~419.9 m,具有分布广、变化大等特点,沉积中心分别位于重庆-合江一带、利川-彭水一线,整体上呈现"山字型"展布特征;2)膏盐岩岩性组合类型可分为:白云岩或泥(砂)岩夹膏盐岩组合、膏盐岩与白云岩呈韵律性互层组合、膏盐岩夹白云岩或页岩组合,分别发育于潮上带、潮上带相对低洼处及潮上带-潮间带上部水体较深且循环受限的凹陷处;3)膏盐岩主要形成于川东南静水潟湖、其次为川东及川西南扰动潟湖与混积潮洼,即"一主两副"的多潟湖环境。
The structural setting of the Sichuan Basin in the latter part of the Early Cambrian epoch appears as a single depression between two uplifts. The climate was hot and dry,favoring the development of gypsum-salt rocks,which characteristics were analyzed in a combination of field profile,drilling section,thin section and regional geological survey. The present study of lithofacies paleogeography of gypsum-salt rocks compares the diverse hydrodynamic characteristics,sedimentary structure,single-layer thickness,development of areal scale and location,and finally establishes a sedimentary model of Early Cambrian gypsum-salt rocks in the Sichuan Basin,with the following results.(1)The gypsum-salt rocks mainly comprise gypsum-bearing dolomite and gypsum rocks from 0.74 m to 419.9 m thick. The sedimentary centers are located in the Chongqing-Hejiang and Lichuan-Pengshui areas. The overall distribution characteristics are"mountain type".(2)The lithological association of gypsum-salt rocks falls into three categories:association of dolomite or mudstone(sand)rocks with gypsum-salt rocks,developed in the upper tidal zone;rhythmically interbedded associations of gypsum-salt rocks and dolomite in relatively shallow,low-lying areas in the upper tidal zone;and the association of gypsum-salt rocks with dolomite or shale in deeper depressions with restricted circulation in the upper-to inter-tidal zone.(3)In multiple-lagoons(one main lagoon and two subsidiary lagoons),the gypsum-salt rocks were formed mainly in static lagoons in southeastern Sichuan,with two subsidiary lagoons in disturbed lagoons in eastern Sichuan and in mixed tidal depressions in southwestern Sichuan.
作者
顾志翔
何幼斌
彭勇民
罗进雄
刘小帆
张锦
聂鸿宇
GU ZhiXiang;HE YouBin;PENG YongMin;LUO JinXiong;LIU XiaoFan;ZHANG Jin;NIE HongYu(School of Geosciences,Yangtze University,Wuhan 430100,China;Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Yangtze University,Wuhan 430100,China;Petroleum Exploration and Development Research Institute,SINOPEC,Beijing 100083,China)
出处
《沉积学报》
CAS
CSCD
北大核心
2019年第4期834-846,共13页
Acta Sedimentologica Sinica
基金
国家科技重大专项（2011ZX05004-001-004）~~
关键词
四川盆地
下寒武统
膏盐岩
沉积特征
多潟湖模式
Sichuan Basin
Lower Cambrian
gypsum-salt rocks
sedimentary characteristics
multiple-lagoon mode
