【作者】 汪洋； 姬广义； 邓晋福；

【Author】 WANG Yang JI Guang-yi ,DENG Jin-fuGuangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou 510640, China; Division of Petrology, China University of Geosciences , Beijing 100083, China; Geological Institute of Beijing Municipality, Beijing 100011, China

【机构】 中国科学院广州地球化学研究所； 北京市地质研究所； 中国地质大学地球科学与资源学院；

【摘要】 根据燕山地区侏罗纪—早白垩世岩浆岩的同位素年代学和化学成分资料,以及该地区构造变形序列,初步总结了燕山造山带岩浆活动时间序列和岩性组合:第一阶段的代表是早侏罗世英安岩和玄武岩;第二阶段以中侏罗世中性火山岩和闪长岩-石英二长岩/花岗闪长岩-花岗岩侵入岩组合为标志;第三阶段表现为晚侏罗世中、酸性火山岩和闪长岩-石英二长岩-正长岩-花岗岩侵入岩组合的活动;第四阶段为早白垩世早期安粗岩和流纹岩以及闪长岩-石英二长岩-正长岩-碱性正长岩-花岗岩侵入岩组合为标志;第五阶段以120Ma以后发育的小规模火山岩和花岗岩-碱性花岗岩组合为标志。与之相对应,燕山造山带侏罗纪-白垩纪造山过程演化模式为:玄武岩底侵、地壳物质熔融形成安粗岩和流纹岩岩浆→地壳被加热并弱化→推覆构造发育、地壳增厚→后造山崩塌。更多还原

【Abstract】 According to the chronological and geochemical data of Jurassic-Early Cretaceous magmatic rocks and the sequence of tectonic events, the framework of magrnatism sequence from the Early Jurassic to Early Cretaceous in the Yanshan orogen, North China was proposed. Early Jurassic dacite and basalt represent the first magmatic stage. The second stage is represented by intermediate volcanic rocks and diorite-quartz monzonite/granodiorite-granite assemblage of Middle Jurassic. Intermediate and acid volcanic rocks and diorite-quartz monzonite-syenite-granite assemblage were developed in the third stage during Late Jurassic. In the Early Cretaceous, two stages of magrnatism were developed. The earlier stage (fourth) is marked by latite and rhyolite in strata and diorite-quartz monzonite-syenite-alkaline syenite-granite assemblage,whereas the later stage (fifth) is represented by small scale volcanic activities and alkaline granite-granite assemblage after 120 Ma. Based on the temporal variations of igneous petrologic assemblages and their geochemical signatures as well as tectonic style, the general model for orogenic process of the Yanshan belt is described as: basaltic underplating and formation of latite or rhyolite magma→crustal heating and rheological weakening→thrust developing and crustal thickening→post-orogenic collapse.更多还原