汾河裂谷晋中盆地内第四纪沉积序列与沉积环境恢复  

Quaternary sedimentary sequence and sedimentary environment restoration in the Jinzhong Basin,Fenhe Rift Valley

作　　者：秦帮策 方维萱[1,2] 张建国[2] 贾润幸[2] 肖文进[2] QIN Bangce;FANG Weixuan;ZHANG Jianguo;JIA Runxing;XIAO Wenjin(Kunming University of Science and Technology,Faculty of Land Resource Engineering,Kunming 650000,Yunnan,China;Mine Ecological Environment Resources Innovation Laboratory,Non-ferrous Metal Minerals Geological Survey Center,Beijing 100012,China;Southwest Institute of Geological Survey,Non-ferrous Metal Minerals Geological Survey Center,Kunming 650000,Yunnan,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650000 [2]有色金属矿产地质调查中心矿山生态环境资源创新实验室,北京100012 [3]有色金属矿产地质调查中心西南地质调查所,云南昆明650000

出　　处：《地质力学学报》2021年第6期1035-1050,共16页Journal of Geomechanics

基　　金：中国地质调查局地质调查项目(DD20190593);云南省地质过程与矿产资源创新团队(2012)项目。

摘　　要：晋中盆地是位于汾渭地堑系中部的新生代陆内断陷沉积盆地,研究晋中盆地第四纪的沉积序列对于进一步认识该盆地区域构造和区域气候环境变化具有重要意义。为查明晋中盆地第四纪沉积序列结构、研究揭示晋中盆地第四纪沉积环境及演化,通过构造岩相学方法,对晋中盆地地表和钻孔内第四纪沉积物和沉积环境进行了研究。结果表明:晋中盆地清徐地区地表第四纪沉积序列结构为盆地内部沱阳组河床相和河漫滩相-盆地边缘汾河组河流相—盆山过渡带峙峪组河流相、汾河组冲积扇相及马兰组风积相-基岩山地(盆地外围)二叠系浅海相。钻孔岩芯内第四纪沉积序列结构为下更新统浅湖相和滨湖相—中更新统浅湖相和河流相—上更新统河流相和冲积扇相—全新统冲积扇相。研究认为晋中新生代陆内断陷盆地内沉积序列和演化结构为早更新世陆相湖盆沉积环境—中更新世萎缩湖泊环境—晚更新世强烈萎缩的湖泊和河流环境—全新世再度沉降的陆相湖盆;陆相湖盆从中心向山地沉积环境分带为湖泊沉积环境—河流和湖泊沉积环境—冲积扇沉积环境(盆地边缘出山口区)。盆山过渡带地区上更新世沉积物错位现象与同沉积活动断裂有关,断裂活动性揭示了晋中盆地阶梯式断陷成盆的动力学机制。这些研究成果为区域气候环境变化和晋中盆地区域构造研究提供了新证据,也为太原市城市群建设中工程场址的选择提了供参考。Jinzhong Basin is a Cenozoic intracontinental faulted sedimentary basin located in the middle of Fen-Wei graben system. Our study aims to identify the Quaternary sedimentary sequence and reveal the Quaternary sedimentary environmental evolution of the Jinzhong Basin. We used structural petrography to survey the Quaternary sediments and sedimentary environment on the surface and in the boreholes of the Jinzhong Basin. The results shows: The surface Quaternary sedimentary sequence in the Qingxu area of the Jinzhong Basin is composed of the river bed facies and floodplain facies of the Tuoyang Formation in the basin—the fluvial facies of the Fenhe Formation at the basin edge—the fluvial facies of the Zhiyu Formation, alluvial fan facies of the Fenhe Formation and aeolian facies of the Malan Formation in the basin-mountain transition zone—Permian neritic facies in the bedrock mountain(the periphery of the basin). The Quaternary sedimentary sequence in the core of the borehole is composed of the shallow lake facies and lakeside facies of the Lower Pleistocene—the shallow lake facies and fluvial facies of the Middle Pleistocene—the fluvial facies and alluvial fan facies of the Upper Pleistocene—the alluvial fan facies of the Holocene. The study suggests that the sedimentary sequence and environmental evolution of the Jinzhong basin is the early Pleistocene continental lake basin sediment—the Middle Pleistocene shrunken lake—the late Pleistocene strongly shrunken lake and river—the Holocene re-subsidence terrestrial lake pots. From the center to the mountain the sedimentary environment of the continental lake basin can be divided into lake sediment—river and lake sediment—alluvial fan sediment(the mountain mouth area at the edge of the basin).The dislocation of Upper Pleistocene sediments in the basin-mountain transition zone was caused by syn-sedimentary active faults. The fault activity reveals the dynamic mechanism of stepped formation in the Jinzhong Basin. These findings provide new evidence f

关 键 词：晋中盆地 第四纪 沉积序列 沉积环境 活动断裂 

分 类 号：P534.63[天文地球—第四纪地质学] P586[天文地球—古生物学与地层学]