摘要
通过对吉林省石头口门地区早二叠世砂岩进行野外地质考察、薄片镜下观察和碎屑锆石U-Pb年代学研究,探讨其形成时代、物源及构造环境。长石岩屑杂砂岩的碎屑颗粒具有分选和磨圆度差以及成分复杂的特征,表明为近源快速堆积的产物。获得114颗碎屑锆石U-Pb年龄介于480~276 Ma,可划分出晚石炭世—早二叠世(322~276 Ma)和早石炭世(349~323 Ma) 2个主要年龄组,另有4个早古生代和中泥盆世年龄。通过区域岩浆事件对比,推测石头口门地区早二叠世砂岩的物源主要来自华北板块北缘晚石炭世—早二叠世活动陆缘型岩浆岩,少量来自研究区附近的早石炭世岩浆岩、早古生代岩浆弧、晚志留世—中泥盆世弧-陆碰撞岩浆岩以及华北板块前寒武纪变质基底。综合碎屑锆石年龄频谱、沉积以及构造背景资料分析,认为石头口门早二叠世砂岩应是活动大陆边缘环境下海底扇沉积序列的组成部分,并在古亚洲洋闭合过程中作为基质与一系列成分、规模和时代复杂的构造岩块或岩片共同构成了蛇绿混杂岩。
We present detailed field geological investigations,petrographic observations,and detrital zircon U-Pb data studies of Early Permian sandstones in the Shitoukoumen area,Jilin Province,to discuss their age,provenance and tectonic settings.The Shitoukoumen lithic graywacke is characterized by poor sorting and roundness,as well as complex composition,implying that it is the result of short distance transport and quick accumulation.The U-Pb ages of the 114 obtained detrital zircons range from 480 to 276 Ma,which can be divided into two main age groups:Late Carboniferous-Early Permian(322~276 Ma) and Early Carboniferous(349~323 Ma).There are four other ages of Early Paleozoic and Middle Devonian.By comparing the regional magmatic events,we speculate that the clastic materials of Early Permian sandstones are mainly derived from the Late Carboniferous-Early Permian active continental margin magmatic rocks in the northern margin of the North China Block.Besides,the Early Carboniferous magmatic rocks,the Early Paleozoic magmatic arc,and the Devonian arc-continent collisional magmatic rocks near the study area,together with the Precambrian metamorphic basement of North China Craton,contribute a small number of debris.According to the comprehensive analysis of spectral characteristics of detrital zircon ages,sedimentary features,and tectonic background of the study area,we infer that the Early Permian sandstone should belong to a submarine fan that was formed in an active continental margin setting.As the base materials,the Early Permian standstones in the Shitoukoumen area,together with a series of tectonic rocks and slices with complex components,scales and ages,constitute the ophiolitic mélange during the closure of the Paleo-Asian Ocean.
作者
宋志刚
丛文爽
张天宇
高丽华
马启合
韩作振
SONG Zhigang;CONG Wenshuang;ZHANG Tianyu;GAO Lihua;MA Qihe;HAN Zuozhen(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Key Laboratory of Depositional Mineralization&Sedimentary Mineral of Shandong Province,Shandong University of Science and Technology,Qingdao 266590,China;Qingdao Geological Exploration Institute of China Metallurgical Geology Bureau,Qingdao 266109,China)
出处
《山东科技大学学报（自然科学版）》
CAS
北大核心
2024年第1期41-52,共12页
Journal of Shandong University of Science and Technology(Natural Science)
基金
国家自然科学基金项目(42302244)。
关键词
碎屑锆石
砂岩
二叠纪
活动大陆边缘
石头口门地区
detrital zircon
sandstone
Permian
active continental margin
Shitoukoumen area
