摘要
文章采用激光剥蚀-电感耦合等离子质谱仪(laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS)方法对苏北盆地高邮凹陷新生代辉绿岩4个样品进行锆石U-Pb年代学研究,获得的岩浆结晶年龄分别为(45.3±1.3)、(59.8±1.7)、(40.5±0.7)、(44.8±1.1)Ma,指示其形成时代为古新世和始新世,表明苏北盆地岩浆活动具有多期性的特点。苏北盆地在新生代时期的发育过程受郯庐断裂带及太平洋板块俯冲后撤的影响,总体上处于太平洋板块俯冲后撤形成的弧后拉张环境,其中早期岩浆活动明显受郯庐断裂带伸展活动的控制。锆石U-Pb年代学特征显示,在吴堡期2套辉绿岩就已经开始上升侵位,而并非是相关文献中的三垛期。此次工作获得的锆石年龄多集中于40.5~45.3 Ma,而其北西侧的渤海湾盆地新生代锆石年龄多集中于60~50 Ma,造成该现象的原因可能是太平洋板块俯冲后撤引起的弧后伸展区域变迁。
The U-Pb geochronology of zircon from four samples of Cenozoic diabase in Gaoyou Sag,Subei Basin was studied by laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS).The magmatic crystallization ages obtained from the four samples are(45.3±1.3),(59.8±1.7),(40.5±0.7)and(44.8±1.1)Ma,respectively,indicating that their formation ages are Paleocene and Eocene,which shows that the magmatic activity in Subei Basin has the characteristics of multiple periods.The development process of Subei Basin in Cenozoic was influenced by the Tan-Lu fault zone and the subduction and retreat of the Pacific plate,which was generally in the back-arc tension environment formed by the subduction and retreat of the Pacific plate,and the early magmatic activity was obviously controlled by the extensional activity of the Tan-Lu fault zone.Zircon geochronology characteristics show that two sets of diabase began to rise and emplace in the Wubao period,instead of the Sanduo period in the related literatures.The zircon ages obtained in this work are mostly concentrated in 40.545.3 Ma,while the Cenozoic zircon ages in Bohai Bay Basin on the northwest side are mostly concentrated in 6050 Ma,which may be due to the change of back-arc extension area caused by subduction and retreat of the Pacific plate.
作者
谢成龙
荆翰林
王力
娄国泉
刘传泽
XIE Chenglong;JING Hanlin;WANG Li;LOU Guoquan;LIU Chuanze(School of Resources and Environmental Engineering,Hefei University of Technology,Hefei 230009,China;Geophysical Prospecting Research Institute,Jiangsu Oilfield Company,SINOPEC,Nanjing 210046,China)
出处
《合肥工业大学学报（自然科学版）》
CAS
北大核心
2021年第4期543-549,562,共8页
Journal of Hefei University of Technology：Natural Science
基金
国家自然科学基金资助项目(41772210)。
