摘要
秭归盆地侏罗纪地层完整记录了秦岭-大别造山带及黄陵背斜隆升剥蚀演化历史。通过对秭归盆地侏罗纪地层沉积相及砂岩碎屑组分的系统分析,结合碎屑锆石U-Pb年龄谱和低温热年代学数据,探讨了秭归盆地沉积充填及与周缘造山带盆-山构造演化过程。秭归盆地下侏罗统桐竹园组古水流方向自北北西向南南东,砂岩成分成熟度较高,盆地沉积物主要来源于北北西方向的南秦岭地区。中侏罗统砂岩长石及岩屑含量明显增多,古水流方向为南西向,位于盆地北东方向的秦岭-大别造山带成为盆地主要物源区。中侏罗统砂岩碎屑组分的垂向变化记录了秭归盆地东北部秦岭-大别造山带强烈的隆升作用。上侏罗统蓬莱镇组继承中侏罗统上沙溪庙组部分物源区,但上侏罗统砂岩的碳酸盐岩岩屑含量明显增加,暗示秭归盆地周缘碳酸盐岩区域成为新的物源区。低温热年代学数据显示,秭归盆地东侧的黄陵背斜表现为差异性隆升剥蚀过程。晚侏罗世,黄陵背斜南部开始抬升剥蚀,为秭归盆地提供部分物源。早白垩世,黄陵背斜整体隆升。秭归盆地沉积物源及黄陵背斜隆升过程反映了区域应力场由近南北向挤压到早白垩世早期近东西挤压的转变。
The Jurassic strata in the Zigui Basin fully recorded the uplift and denudation evolution of the Qinling-Dabie orogenic belt and the Huangling anticline.Through systematic analyses of the sedimentary facies and sandstone clastic components of the Jurassic strata in the Zigui Basin,combined with U-Pb ages of clastic zircon and low-temperature thermochronological results,the sedimentary filling of the Zigui Basin and basin-and-range tectonic evolution in the peripheral orogenic belt are discussed in this paper.The paleocurrent direction of the Lower Jurassic Tongzhuyuan Formation in the Zigui Basin is from NNE to SSW,and the sandstone has high detrital maturity.The sediments mainly came from the South Qinling region NNW of the basin.The contents of feldspar and lithic debris in the Middle Jurassic sandstone increase significantly along the SW-oriented paleocurrent,reflecting that the Qinling-Dabie orogenic belt in the northeastern part of the basin turned into the main provenance area of the basin.Vertical variations of sandstone clastic components in the Middle Jurassic recorded the strong uplifting of the Qinling-Dabie orogenic belt in the northeastern part of the Zigui Basin.The Upper Jurassic Penglaizhen Formation inherited some provenance areas of the Middle Jurassic Shangshaximiao Formation.While the increase of carbonate debris in the Upper Jurassic Formations indicates that the carbonate rock area around the Zigui Basin became a new provenance area during the Late Jurassic.The low temperature thermochronological data showed that the Huangling anticline on the eastern side of the Zigui Basin underwent a differential uplift and denudation process.The southern part of the Huangling anticline was uplifted and denuded in the Late Jurassic and provided part of the provenance for the Zigui Basin,whereas the whole Huangling anticline was uplifted in the Early Cretaceous.The source of sediments in the Zigui Basin and the uplift process of the Huangling anticline reflect the transformation of regional stress field from near N-S compression to near E-W compression in the Early Cretaceous.
作者
郑志锋
闫义
单业华
赵奇
张增杰
ZHENG Zhifeng;YAN Yi;SHAN Yehua;ZHAO Qi;ZHANG Zengjie(CAS Key Laboratory of Ocean and Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 51064,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2020年第5期864-880,共17页
Geotectonica et Metallogenia
基金
中国科学院科技先导项目B类(XDB18030104)
国家自然科学基金项目(41676048、U1701641)联合资助。
关键词
秭归盆地
侏罗纪
碎屑组分
古水流
物源分析
黄陵背斜
Zigui Basin
Jurassic
clastic component
paleocurrent
provenance analysis
Huangling anticline
