摘要
【目的】沉积盆地中碎屑沉积物的物质组成变化与源区的隆升剥蚀过程紧密相关。华北克拉通南缘作为中国大陆的主要构造单元,拥有二叠纪较为完整的地质记录,中条山地区位于华北克拉通南部汾渭地堑系核心部位,物源主要指向华北克拉通南缘及相邻的秦岭造山带,是研究二叠纪时期秦岭造山带及相邻地区构造演化过程的理想场所。【方法】通过对华北克拉通南缘中条山地区米汤沟剖面二叠系山西组潮坪-潟湖相含煤岩系及其上覆下石盒子组冲积扇-河流相沉积碎屑锆石U-Pb年代学分析,系统开展沉积物源对比示踪,综合讨论了沉积物源与源区构造作用的相互耦合关系。【结果和结论】结果表明:二叠系山西组潮坪-潟湖相含煤岩系碎屑锆石年龄序列具有297、327、443、921、969、1 826、1 990、2 272、2 443 Ma 9个主要峰值;下石盒子组冲积扇-河流相沉积碎屑锆石年龄序列具有305、1 755、1 882、2 284、2 490 Ma 5个峰值,缺少新元古代和早古生代的碎屑锆石年代记录。分析认为二叠系山西组含煤岩系物源主要来自于北秦岭-华北克拉通南缘构造带,下石盒子组沉积物源仅来自于华北克拉通南缘构造带。二者的沉积物源差异响应了早中二叠世华北板块与秦岭-大别板块的相互作用过程,显示构造活动自南向北逐渐迁移。早二叠世早中期,华北南缘整体隆升幅度较低,北秦岭构造带的物源能够进入中条山地区;早二叠世晚期至中二叠世早期,由于华北克拉通南缘的快速抬升,隆升幅度较大,阻隔了南部的北秦岭物源,导致中条山地区不再接受北秦岭的物源供给。研究成果从沉积学角度为华北克拉通南缘及相邻秦岭造山带在二叠纪时期的构造活动过程提供了新的佐证。
[Objective]The changes in the material composition of detrital sediments in a sedimentary basin are intimately associated with the uplift and denudation processes of provenance areas.The southern margin of the North China Craton,a primary tectonic unit of the continental area of China,preserves relatively complete geological records of the Permian.The Zhongtiao Mountain area is located in the core of the Fen-Wei graben system on the southern margin of the North China Craton,with the southern margin of the North China Craton and the adjacent Qinling orogenic belt potentially serving as its provenance areas.Therefore,the Zhongtiao Mountain area is an ideal site for exploring the tectonic evolutionary processes of the Qinling orogenic belt and its adjacent areas during the Permian.[Methods]This study examined the detrital zircon U-Pb chronology of the coal-bearing rock series of the tidal flat-lagoon facies in the Permian Shanxi Formation and sediments of the alluvial fan-fluvial facies in the overlying Lower Shihezi Formation within the Mitanggou section of the Zhongtiao Mountain area.Then,this study delved into the correlation and tracing of sediment provenance areas.Finally,this study comprehensively explored the coupling between sediment provenance and tectonic processes in the provenance areas.[Results and Conclusions]The results indicate that the coal-bearing rock series of the tidal flat-lagoon facies in the Permian Shanxi Formation exhibit nine primary detrital zircon age peaks:297,327,443,921,969,1826,1990,2272,2443 Ma.In contrast,the sediments of the alluvial fan-fluvial facies in the Lower Shihezi Formation manifest five detrital zircon age peaks,namely 305,1755,1882,2284,2490 Ma,lacking the age records of Neoproterozoic and Eopaleozoic detrital zircons.The analysis reveals that the coal-bearing rock series originate primarily from the North Qinling orogenic belt and the southern margin of the North China Craton.In comparison,the sediments of the alluvial fan-fluvial facies are merely derived from the sou
作者
吴芳
李振宏
井向辉
寇琳琳
杜壮
刘博华
WU Fang;LI Zhenhong;JING Xianghui;KOU Linlin;DU Zhuang;LIU Bohua(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Key Laboratory of Paleomagnetism and Tectonic Reconstruction,Ministry of Natural Resources,Beijing 100081,China;Research Institute of Exploration and Development,Changqing Oilfield Branch Company,PetroChina,Xi’an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2024年第11期37-54,共18页
Coal Geology & Exploration
基金
中国地质调查局地质调查项目(DD20221644)
国家自然科学基金项目(41972119)。
关键词
含煤岩系
锆石年代学
华北克拉通
秦岭造山带
沉积物源
coal-bearing rock series
zircon chronology
North China Craton
Qinling orogenic belt
sediment provenance
