Geochronology and Geochemical Characteristics of the Nandu Syenite in SE Guangxi and Its Implications
详细信息
- 责任者：Chen Xinyue (Department of Geology ; Hunan University of Science and Technology ; Xiangtan 411201 ; China) ; Wang Yuejun
- 刊名：Geotectonica et Metallogenia
- 出版年：2013
- 卷期：37(2)
- 关键词：正长岩 ; syenites ; 元素地球化学 ; elements geochemistry ; 广西 ; Guangxi Province
- 页码：p.284-293
- 图表：illus., 3 tables, 60 refs.
- 分类号：0801
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
摘要
The Nandu syenite shows SiO2= 62. 7% ～ 64. 2%,K2O + Na2O = 11. 2% Wang Y.1994.The Kuiqi peralkaline granitic complex(SE China):Petrology and geochemistry.Journal of Petrology,35(4):983-1015. 12. 3%,K2O = 6. 47% ～ 9. 06% with high K2O / Na2O of 1. 37 ～ 2. 80. It can be defined as shoshonitic series rocks. These rocks are characterized by enrichment of LREE and LILE,with slight Eu negative anomalies( δEu = 0. 48 ～ 0. 74),and significant Sr and P-Ti negative anomalies but insignificant Nb-Ta negative anomalies. Their εNd( t) values range from+ 0. 32 to + 0. 84. Such signatures show an affinity to intraplate shoshonitic rocks. LA-ICP-MS zircon U-Pb dating of the Nandu syenite yields an age of 162 ± 1 Ma with MSWD = 0. 1( n = 23),which is interpreted as the crystallization age. Such an age is consistent with those in southeast Guangxi and south Jiangxi provinces. Our new data,together with the available data,indicate a middle Jurassic intraplate extensional tectonic regime in South China.