吉林南部通化地区集安群的年代学

对辽吉裂谷带吉林段集安群火山岩和碎屑沉积岩以及裂谷带内的花岗岩进行了LA-ICP-MS锆石U-Pb的年代学研究.测年结果显示, 集安群火山岩形成于2156~2189Ma, 并于1870~1 881Ma接受区域变质作用改造.伴随集安群的火山-沉积和变质作用, 有2期花岗岩侵入: 一期形成于裂陷期的2156~2189Ma; 另一期形成于造山期的1870~1881Ma.同时, 碎屑锆石和捕获锆石获得了2471~2494Ma和2633~2653Ma的岩浆成因锆石年龄, 代表结晶基底的2次岩浆事件.集安群的物质来源于太古宙基底和裂陷期的岩浆事件产物. 

Geocgronology of Ji' an Group in Tonggua Area,Soutgern Jilin Province

The chronology of volcanic and sedimentary rocks of Ji'an Group, and the granites of the Tonghua area of the Liaoji rift zone by the LA-ICP-MS zircon U-Pb dating are studied in the paper. The results show that the Ji'an Group formed in 2156 to 2189Ma, and subsequently underwent regional metamorphism between 1870 and 1881Ma.Accompanied by the volcanic-sedimentation and the metamorphism of the Ji'an Group, two periods of granitic intrusions occurred; one was at 2156 to 2189Ma during the rifting stage, whereas the other at 1870 to 1881Ma during the orogenic period. In addition, ages of magmatic zircons from the detrital zircons and the inherited zircons peaked at 2471 to 2494Ma and 2633 to 2653Ma, representing two magmatic events of the crystalline basement. Sedimentary provenance of the Ji'an Group was derived from the Archean basement and products of the magmatism during the rifting events.