【摘要】 为厘定长乐-诏安断裂带的形成时代及活动峰期,运用激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)锆石U-Pb测年法对平潭辉绿岩墙、二长花岗岩围岩及南日岛动力变质花岗闪长岩开展了测年工作,结果表明带内大规模花岗质岩石的形成与大型走滑活动是同期的,辉绿岩墙结晶年龄代表断裂带走滑剪切形成深切地壳张性破裂时间,辉绿岩中捕获的继承岩浆锆石年龄较老,最新结晶锆石年龄为131 Ma,围岩的锆石年龄加权平均值为(133. 4±0. 8) Ma,动力变质花岗岩锆石的年龄加权平均值为(130. 3±1. 0) Ma。首次发现的假玄武玻璃是对早白垩世断裂带强烈活动形成的古地震事件的记录,该带的基底可能为华夏古陆的一部分,其初始形成时代主要为侏罗纪-早白垩纪。更多还原

【Abstract】 In order to determine the formation age and active peak periods of the Changle-Zhaoan fault zone,the Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U-Pb dating method was taken for the Pingtan diabase,the monzonite granite,and the NanriDao dynamic metamorphic granodiorite. the results shows that the formation of large-scale granitic rocks in the belt was in the same period as large-scale strikeslip events,and that the crystallization age of the diabase represents the time that tension fracture cuttered the crust under the strike-slip movement. The results show that the inherited magmatic zircons captured in diabase are relatively old. The age of the latest crystalline zircon is 131 Ma. The age-weighted average of zircons in surrounding rocks is (133. 4 ± 0. 8) Ma,and the age-weighted average of zircons in the dynamic metamorphic granodiorite is (130. 3 ± 1. 0) Ma. The pseudotachylite is first discovered as a record of paleoearthquake events formed during the intense activity of the Early Cretaceous on fault zone. The basement of this zone may be part of the Huaxia ancient land,and its initial formation and activity age is mainly in late Jurassic-Early Cretaceous.更多还原