广西苍梧寒武纪沉积环境及其对大地构造的响应  

Sedimentary environments of the Cambrian sequence in Cangwu,Guangxi and its response to geotectonics

作　　者：裴羽[1] 何幼斌[1] 游国庆[2] 李佐峰[1] 刘溪茜 邢杨[1] 

机构地区：[1]长江大学地球科学学院,武汉430100 [2]中国地质科学院地质研究所,北京100037

出　　处：《中国科技论文》2015年第21期2488-2494,共7页China Sciencepaper

基　　金：中国地质科学院地质研究所专题合作研究项目(D2801-18)

摘　　要：运用岩性、古生物等相标志分析桂东苍梧地区寒武纪沉积环境。以"构造控盆、盆地控相、相控组合"思路为指导,结合鄂西、湘西北、湘中、黔中南、桂北、湘南、赣西南和粤西北地区的寒武纪沉积环境的水深变化规律,分析华南寒武纪大地构造环境。小内冲组岩石类型主要为中层粉砂岩和泥质粉砂岩夹薄层泥岩,形成于较深水的盆地边缘至斜坡环境。黄洞口组沉积物以中厚层细砂岩和粉砂岩夹中薄层泥岩为主,夹含砾杂砂岩、杂砂岩和炭质泥岩等,相对于小内冲组,岩石类型变粗,水体变浅,沉积环境过渡为斜坡至浅海陆棚。总体上,桂东苍梧地区寒武纪沉积环境以斜坡为主。在平面上,从北西至南东方向,华南寒武纪沉积环境依次为台地、陆棚、斜坡、盆地边缘、盆地、盆地边缘和斜坡,水体整体呈现浅-深-浅的变化。说明扬子板块和华夏板块的界线可能位于桂北—湘中和桂东—湘南地区之间,湘南、桂东、赣西南和粤西北地区应位于华夏板块内,其在寒武纪处于被动大陆边缘环境中,距桂东—湘南地区南东侧不远处可能存在古陆。Lithologic and paleontologic markers are used to analyze sedimentary environments of the Cambrian in Cangwu, Guan gxi. Guided by thoughts＂tectonics controlling basin, basin controlling facies, facies controlling deposits＂, in combination with water depth data of Cambrian deposits in western Hubei, northern Guangxi, southern Hunan, southwestern Jiangxi northwestern Hunan, central Hunan, central and southern Guizhou, and northwestern Guangdong, tectonic environments of South China during the Cambrian are analyzed. The Xiaoneichong Formation mainly consists of medium thick-bedded sihstones, pelitic silt stones intercalated by thin-bedded mudstones, deposited in basin margin to slope. The Huangdongkou Formation is composed of medium thick bedded fine sandstones, siltstones intercalated by medium thin bedded mudstones, which are relatively coarser than the underlying Xiaoneichong FormatiorL Comparably, water depth became shallower upward and sedimentary environment was transitioned to slope to shallow sea. Overall, the Cambrian sedimentary environments in Cangwu, eastern Guangxi were basically slope. Horizontally, from northwest to southeast, the Cambrian sedimentary environments of South China were platform, shelf, slope, basin margin, basin, slope in turn, and water depth fell after increased. It shows that the boundary between Yangtze plate and Cathaysian plate may lie between northern Guangxi to central Hunan and eastern Guangxi to southern Hunan. Southern Hu nan, eastern Guangxi, southwestern Jiangxi and northwestern Guangdong are supposed to be located within Cathaysian plate, which are situated on a passive continental margin during Cambrian. Besides, an ancient land might exist in an area of the south- east of eastern Guangxi to southern Hunan.

关 键 词：地质学 广西苍梧 寒武纪 相标志 大地构造 沉积响应 

分 类 号：P541[天文地球—构造地质学] P534.41[天文地球—地质学]