地质科学2013，Vol.48Issue(2)：557-568,12.DOI:10.3969/j.issn.0563-5020.2013.02.016
峨眉山大火成岩省底部枕状玄武岩的地质地球化学特征及成因探讨
The Shangcang pillow lavas from the bottom of the Emeishan Large Igneous Province, southwestern China:Petrogenesis and tectonic implications
摘要
Abstract
The Shangcang Permian pillow basalts in Yunnan Province crop out on the bottom of the inner zone of the Emeishan Large Igneous Province ( ELIP). They are belong to tholeiitic series with SiO2 contents between 49.36% and 51.36% , 1.28% ～ 1.91% for TiO2, 13.91% ～ 16.31% for A12O3, 6. 08%-10. 79% for MgO,with Mg#[ 100xMg/(Mg+Fe) ]of 53～69,and the Na2O contents of them between 1. 59% and 3. 72% ,higher than K2O(0. 18%～0. 76% ) , corresponding the high Na2O/K2O ratios (4. 27 to 10. 48). These basalts are enriched in LREE and LILE with ( La/Sm ) N values of 1.4～2.2, and ( Ce/Yb ) N values of 2. 2～3.4, but lower than those of OIB(2. 3 and 9. 6) ,they instead have the N-MORB affinity in HREE and HSFE, while the characteristics of LREE and LILE are considered as the mixing result of N-MORB and the upper crust. In the Th/Hf-Ta/Hf tectonic diagrams,these pillow basalts plot in the fields of continental marginal rift tholeiitic series rocks, thus the Shangcang pillow basalts are considered as the spreading products of the initial continental marginal rift caused by the subduction of Paleo-Tethys ocean under the edge of Yangtze terrane.关键词
枕状玄武岩/上沧/陆缘裂谷/峨眉山大火成岩省Key words
Pillow basalts, Shangcang, Continental marginal rift, Emeishan Large Igneous Province分类
天文与地球科学引用本文复制引用
郝艳丽,黄启帅,张晓冉,龚小晗,史仁灯..峨眉山大火成岩省底部枕状玄武岩的地质地球化学特征及成因探讨[J].地质科学,2013,48(2):557-568,12.基金项目
中国地质科学院地质研究所基本科研业务费项目(编号:J0914)资助. （编号:J0914）
