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秦祁结合部位王家岔石英闪长岩体锆石LA-ICPMS定年及地质意义
LA-ICPMS Zircon U-Pb Dating of a Quartz Diorite Pluton from Wangjiacha,the Junction Area Between the Qinling and Qilian Orogenic Belts and Its Tectonic Significance
【摘要】 出露于秦岭、祁连造山带结合部位的王家岔石英闪长岩体,侵入于变质基底陇山岩群之中。岩石学、岩石化学、地球化学特征显示石英闪长岩侵入体具有俯冲花岗岩特征。利用LA-ICPMS(激光剥蚀等离子体质谱)测年技术,对石英闪长岩进行单颗粒锆石微区U-Pb同位素测定,获得加权平均年龄为(454.7±1.7)Ma,代表了岩石的形成年龄。这一新的成果资料,对研究秦祁结合部位早古生代构造演化、造山过程及秦、祁造山带的关系具有重要意义。
【Abstract】 Wangjiacha quartz diorite,outcropped in the junction area between Qinling and Qilian orogenic belts,was intruded into the metamorphic complex of the Longshan Group.Assemblage,chemistry and geochemical characteristics of the quartz diorite intrusion show the characteristics of subduction granite.Using LA-ICPMS(Laser-iso plasma mass spectrum) dating technique,U-Pb isotope dating for tiny areas of single zircons from the quartz diorite gives a weighted average age of(454.7±1.7) Ma,which probably stands for the formation age of the rocks.This dating is of great significance to the research on the Early Paleozoic tectonic evolution,on the orogenic processes in the junction area between the Qinling and Qilian and on the relationship between the Qinling and Qilian orogenic belts.
【Key words】 Wangjiacha quartz diorite; LA-ICPMS; UPb isotope dating; Qinling and Qilian orogenic belts;
- 【文献出处】 吉林大学学报(地球科学版) ,Journal of Jilin University(Earth Science Edition) , 编辑部邮箱 ,2007年03期
- 【分类号】P597.3
- 【被引频次】95
- 【下载频次】550