SHRIMP zircon U-Pb ages and tectonic implications for Indosinian granitoids of southern Zhuguangshan granitic composite, South China

• Published in: Chinese science bulletin 2012-05, Vol.57 (13), p.1542-1552
• Main Authors: Deng, Ping, Ren, JiShun, Ling, HongFei, Shen, WeiZhou, Sun, LiQiang, Zhu, Ba, Tan, ZhengZhong
• Format: Article
• Language: English
• Subjects: Age; Chemistry/Food Science; China; Dating; Dating techniques; Earth Sciences; Engineering; Granite; Humanities and Social Sciences; Life Sciences; melting; multidisciplinary; Physics; Science; Science (multidisciplinary); Shrimps; SHRIMP锆石U-Pb年龄; Tectonics; Zircon; zirconium; 中国南方; 印支期花岗岩; 复合材料; 岩浆活动; 构造意义; 燕山期花岗岩; 诸广山
• ISSN: 1001-6538; 1861-9541
• DOI: 10.1007/s11434-011-4951-8

The large southern Zhuguangshan granitic batholith composite consists of granites with ages varying from the Caledonian through Indosinian to Yanshanian. Based on K-Ar dating data, the ages of the major parts of this composite were previously regarded as Yanshanian. In this study, the SHRIMP zircon U-Pb dating method has been adopted for six plutons, Ledong, Longhuashan, Dawozi, Zhaidi, Baiyun and Jiangnan, in the southern Zhuguangshan composite, in which the four plutons other than Baiyun and Jiangnan were previously regarded as Yanshanian granites. Magmatic zircons from these six plutons, dated by this study, have yielded ages of 239±5 Ma (MSWD = 2.5), 239±5 Ma (MSWD = 2.5), 239±2 Ma (MSWD = 1.7), 239±4 Ma (MSWD = 3.2), 231±2 Ma (MSWD = 0.81) and 231±3 Ma (MSWD = 1.8), respectively. The results indicate that these plutons were formed by early Indosinian magmatism. Geochemical characteristics suggest that these granites were formed in an extensional tectonic environment. Therefore, the Indosinian period granites in the southern Zhuguangshan composite were formed by partial melting of the Paleo-Mesoproterozoic crustal components during the collapse of thickened lithosphere after the collision between the South China and Indosinian plates.