Tianxin Cretaceous Volcanic Rock in Xingguo, South Jiangxi Province: Zircon U-Pb Dating and Its Tectonic Setting
详细信息
- 责任者：Chen Zhenyu (Key Laboratory of Metallogeny and Mineral Resource Assessment ; Ministry of Land and Resources ; Institute of Mineral Resources ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Wang Denghong
- 刊名：Rock and Mineral Analysis
- 出版年：2012
- 卷期：31(3)
- 关键词：火山岩 ; volcanic rocks ; 铀—铅计时 ; U-Pb dating ; 江西 ; Jiangxi Province
- 页码：p.543-548
- 图表：2 tables,19 refs.
- 分类号：0801
- issnNo：ISSN0254-5357
- isbnNo：CN11-2131/TD
摘要
In this paper, based on field survey, the authors investigate the rock formation time of Tianxin andesitic-porphyrite by Laser Ablation-Multicollector Inductively Coupled Plasma-Mass Spectrometry(LA-MC-ICPMS) zircon U-Pb dating,and determine its age to be(102.3±0.5) Ma.This result indicates that the stratum relation considered before should be adjusted,the Tianxin andesitic-porphyrite must have erupted in the late Cretaceous but not the late Jurassic period,the included sandstone breccia belongs to the early cretaceous Ganzhou group and the stratum covering on the andesitic-porphyrite belongs to the Nanxiong group,not the Ganzhou group.However,this result also indicates that,in this area,the magma activity from early to late was a reverse evolution from acid to neutral to mafic-ultra mafic during the Yanshanian period,and this might be related to the magma activity of the deep mantle,and possibly a production of tectonic event in the South China continental crust from thickening to thinning.