摘要
本文利用LA-ICP-MS锆石U-Pb测定了闽西南上杭溪口复式岩基部分岩体中锆石的U-Pb年龄：田坑里片麻状变晶似斑状中粒二长花岗岩为452.6±7.8 Ma,磜角里中粒花岗分别为161.2±2.9 Ma和168.6±3.7Ma。综合前人年龄资料研究显示：闽西南上杭地区溪口复式岩基是一个多期次侵入的复式岩基,至少经历了3个较大的岩浆活动侵入期,即溪口复式岩基形成经历了440-460 Ma的加里东期,274-394 Ma的华力西期和120-169Ma的燕山期3个较大的岩浆侵入活动时期,燕山期又可分为120-148 Ma和148-169 Ma的中晚期。加里东期形成了二长花岗岩、石英斑岩,华力西期形成了似斑状中细粒花岗岩、斑状花岗岩,燕山期形成了中细粒黑云母花岗岩、正长花岗岩。其中120-169 Ma为溪口复式岩基岩浆活动主要时期,与中国东部大规模燕山期岩浆活动一致,成岩作用可能与岩石圈伸展构造有关。
This paper obtained the U-Pb age data with LA-ICP-MS in fine-grained zircons from the part of the rock of Xikou composite intrusives. The dating result of gneissic metacrystal medium monzonite granite of Tiankengli is 452. 6 ± 7. 8 Ma. The dating result of medium-grained granite of Jijiaoli is 161. 2 ± 2. 9 Ma and 168.6 ± 3. 7 Ma. The results with previous ages studies show that the Xikou composite intrusive was a multiple-intrusive rock foundation in Shanghang area of the southwestern Fujian,and was formed in three stages at least. That is,440- 460 Ma,Caledonian period; 394 - 274 Ma,Variscan period; and 120 - 169 Ma Yanshanian period. However,the Yanshanian period maybe divide into middle and late period. In the first stage,Caledonian period,formed monzogranite and quartz porphyry. In the second stage, Variscan period, formed medium—fine grained porphyraceous granite and porphyritic granite. In the third stage,Yanshanian period,formed medium—fine grained biotite granite and syenogranite. However,120 - 169 Ma was the main magmatic period. This stages of the Xikou composite intrusive was the same as the large-scale magmatic activity in eastern China,and its diagenesis may be related to lithosphere extensional tectonics.
出处
《地质论评》
CAS
CSCD
北大核心
2015年第4期913-924,共12页
Geological Review
基金
中国地质调查局国土资源大调查项目(编号1212011085465)的成果
