CAJ | 학술논문

宁武静乐盆地与浑源盆地位于华北克拉通中北部，侏罗纪地层序列完整，物源指向于阴山燕山造山带中段，通过对盆地内侏罗纪沉积特征的研究，可以演绎华北克拉通北缘侏罗纪的造山过程。在盆地沉积分析的基础上，通过宁武静乐盆地中侏罗统云岗组顶部的凝灰质泥晶碳酸盐岩及浑源盆地上侏罗统髫髻山组玄武安山岩锆石 U Pb 同位素测年，结合国际地层年代表推荐年龄及中侏罗统的沉积速率，对整个侏罗纪沉积序列转换的关键时限进行了限定。研究认为：中侏罗统云岗组底部砾岩沉积时期，侏罗纪沉积演化序列经历了早期湖进至晚期湖退的转换过程，暗示着区域应力场由早期的拉张向晚期的挤压转换，孕育着侏罗纪造山运动的开始，具体时限大约为168 Ma；中侏罗统云岗组顶部凝灰质泥晶碳酸盐岩沉积时期，沉积地层的颜色由其下的灰绿色突变为其上的紫红色，孕育着湖盆地形的突然抬升，区域氧化性增强，气候环境的突变，侏罗纪造山运动进入了快速发展阶段，具体时限为161．0～159．0 Ma；中/晚侏罗世沉积序列具有继承性的发育特征，随着湖盆地形的进一步抬升，侏罗纪沉积范围迅速退至造山带前缘，以砾岩沉积为主，为同期造山运动的产物，侏罗纪造山运动进入了高峰期，具体时限为159．0～153．0 Ma；晚侏罗世晚期，区域上以玄武安山岩及凝灰质角砾岩沉积为主，侏罗纪造山运动进入了造山期后的调整阶段。
저무정악분지여혼원분지위우화북극랍통중북부，주라기지층서렬완정，물원지향우음산연산조산대중단，통과대분지내주라기침적특정적연구，가이연역화북극랍통북연주라기적조산과정。재분지침적분석적기출상，통과저무정악분지중주라통운강조정부적응회질니정탄산염암급혼원분지상주라통초계산조현무안산암고석 U Pb 동위소측년，결합국제지층년대표추천년령급중주라통적침적속솔，대정개주라기침적서렬전환적관건시한진행료한정。연구인위：중주라통운강조저부력암침적시기，주라기침적연화서렬경력료조기호진지만기호퇴적전환과정，암시착구역응력장유조기적랍장향만기적제압전환，잉육착주라기조산운동적개시，구체시한대약위168 Ma；중주라통운강조정부응회질니정탄산염암침적시기，침적지층적안색유기하적회록색돌변위기상적자홍색，잉육착호분지형적돌연태승，구역양화성증강，기후배경적돌변，주라기조산운동진입료쾌속발전계단，구체시한위161．0～159．0 Ma；중/만주라세침적서렬구유계승성적발육특정，수착호분지형적진일보태승，주라기침적범위신속퇴지조산대전연，이력암침적위주，위동기조산운동적산물，주라기조산운동진입료고봉기，구체시한위159．0～153．0 Ma；만주라세만기，구역상이현무안산암급응회질각력암침적위주，주라기조산운동진입료조산기후적조정계단。
Ningwu Jingle basin and Hunyuan basin are located within the north-central of North China craton,and the Jurassic sedimentary sequences are complete from Early Jurassic to Late Jurassic, whose provenance came from the middle of Yinshan Yanshan orogenic belt.Therefore,we may infer the orogenic process by the research of sedimentary sequences in these basin.According to U Pb dating for the tuffaceous micritic limestone at the top of the Yungang Formation in the Middle Jurassic and the basalt-andesite at the bottom of the Tiaojiashan Formation,the recommended age of the Middle Jurassic in the international stratigraphic chart and the sedimentary rate of it,the key limit of the change of Jurassic sedimentary sequences was determined.The Jurassic sedimentary sequences experienced a conversion from the early lacustrine transgressive sedimentation to the late lacustrine regressive one at the bottom of the Middle Jurassic Yungang Formation (J2 yg).It was indicated that the regional tectonic stress field converted from extensional environment to compressional one,giving birth to the beginning of the Jurassic orogenic movement,and the time limit is about 168 Ma.The colors of the tuffaceous micritic limestone on the top of the Yungang Formation in the Middle Jurassic varied from celadon to fuchsia ,indicating a suddenly uplift of the lake basin topography and a quick strengthen of regional oxidizing.The Jurassic orogenic movement experienced a stage of quick development,and the time limit is about 161.0 159.0 Ma.The sedimentary sequence from the Middle Jurassic to the Late Jurassic is continuous and inherited.With the further uplift of the lake basin topography,the sedimentary scope of Jurassic retreated quickly the leading edge of the orogenic belt.It is characterized by the synorogenic conglomerates,while Jurassic orogenic movement reached to the peak period,and the time limit is about 159.0 153.0 Ma.In the Late Jurassic,the regional sedimentary sequences consisted of basalt-andesite and the tuffaceous breccia,the Jurassic orogenic movement came into a post-orogenic adjustment stage.