Geochemical Features and Tectonic Setting of the Yangzhong Rock Mass in the South Part of Ailao Mountains Orogen
详细信息
- 责任者：Zhao Dejun (College of Earth Sciences ; Chengdu University of Technology ; Chengdu 610059 ; China) ; Chen Hongde
- 刊名：Journal of Mineralogy and Petrology
- 出版年：2013
- 卷期：33(1)
- 页码：p.60-68
- issnNo：ISSN1001-6872
- isbnNo：CN51-1143/TD
摘要
According to geochemical characteristics and geological characteristics,the Yangzhong rock mass is mainly rhyolite porphyry,belongs to potassium-rich calc-alkali series.It is showed that the Yangzhong rock mass has A/CNK ratios ranging from 1.2 to 2.3,and AR ratios from 2.69 to 4.28,suggesting that it belongs to typical S-type granite of orogenic granitic magma.REE diagram shows rightward incline and obvious negative Eu abnormity with the ΣREE/ΣHREE ratios ranging from 1.2 to 2.3.Trace element abundance shows that Ta,Nb,Zr,Hf is of negative abnormality while Rb,Th,Ce and Sm of obvious positive abnormality.Analysis of major element,REE elements,trace element abundance shows that the Yangzhong rock mass formed in the extensional stage of post orogenic collision environment.The study of composition of sedimentary clasts,variation of sedimentary facies and magmatic activity demonstrates that the Ailao Mountains oceanic basin ended its extension in the early to middle Permian and entered the stage of collision,which is evidenced by dating of Yangzhong rock mass with 263.1 Ma±2.3 Ma age.