U-Pb Dating of Zircons from the Four-Girl Mountain Pluton in the Songpan-Garze Terrane, and the Relationship between the Pluton and the Wenchuan M_s 8.0 Earthquake of 2008

详细信息   

• 责任者：Dai Zongming (College of Earth Sciences ; Chengdu University of Technology ; Chengdu 610059 ; China) ; Sun Chuanmin
• 刊名：Geology in China
• 出版年：2011
• 卷期：38(3)
• 关键词：花岗岩 ; granite ; 铀—铅计时 ; U-Pb dating ; 龙门山断裂带 ; Longmenshan Fault Zone
• 页码：p.623-636
• 图表：7 illus., 2 tables, 25 refs.
• 分类号：0801
• issnNo：ISSN1000-3657
• isbnNo：CN11-1167/P

摘要

The granitoid intrusions in the eastern part of the Songpan-Garzê terrane were mainly formed in Late Indo-Chinese-Early Yanshanian period, and the Four-Girl Mountain Granite (FGMG) is one of these intrusions. Zircons from FGMG commonly have characteristics of magma zircons. A-ICP-MS zircon U-Pb dating of 23 zircon grains from biotite granodiorite of the FGMG yielded a weighted ²⁰⁶Pb/²³⁸U mean age of (191±1) Ma, which is considered to be the magmatic crystallization age of FGMG. This age has great significance in understanding the initial formation time of the Longmenshan fault belt. Deep geophysical exploration shows that the Four-Girl Mountain area has "roots of mountain", which are made up of many great granitic plutons.