桂林理工大学学报2018，Vol.38Issue(4)：625-639,15.DOI:10.3969/j.issn.1674-9057.2018.04.003
云南威信地区玄武岩的地质地球化学特征及其意义
Geological, geochemical characteristics and its significance of basalts in Weixin area, Yunnan
摘要
Abstract
In order to research the geological and geochemical characteristics of Emeishan basalts at the junction of Yunnan - Guizhou - Sichuan. Field geology,lithology,geochemistry and chronology research on basalts are carried out in Weixin,Yunnan province. The basalts in Weixin area distributed in spots,flake and narrow strip. The main rock types are stomatal-almond basalt and dense block basalts. The results of the LA-ICP-MS zircon U- Pb dating of 5 samples showed that the basalts in the Weixin area were formed in 257. 4 ± 1. 8 Ma and contained a large amount of capture zircon. The analysis of 22 samples shows that the basalt in Weixin area has the major elements characteristics of high Fe(FeOT = 11. 37％ - 14. 72％) ,Mg(MgO = 2. 09％ - 5. 64％) and low K(K2O = 0. 29％ - 1. 99％) ,Na(Na2O = 2. 06％ - 4. 45％) . They are sodium(N2O/K2O = 1. 79 - 10. 90) , subalkaline series of tholeiite basalt(the mean of σ43 is 1. 90 except for three extra-high grains) and are typical high Ti basalt(TiO2 = 4. 18％ - 4. 86％,Ti /Y = 618. 83 - 670. 70) . It has the right steep rare earth distribution mode(ΣREE = 249. 37 × 10 - 6 - 277. 83 × 10 - 6,ΣLREE /ΣHREE 6. 64 - 8. 62) ,and the negative europium anomaly is not obvious(δEu = 0. 91 - 1. 02) . The ratio of incompatible elements(Zr /Nb = 7. 47 - 9. 28, La /Nb = 1. 02 - 1. 16,Ba /Nb = 3. 16 - 19. 00,Ba /Th = 18. 24 - 124. 94,Th /La = 0. 13 - 0. 17,Th /Nb = 0. 14 - 0. 17,Ba /La = 3. 10 - 17. 00,Rb /Nb = 0. 05 - 1. 00) indicates that the basalts in Weixin area with the mixing of crustal materials are continental basalts. Field occurrence,geochemical characteristics and structural environment discriminant diagrams all show that the basalt in Weixin area was formed in continental plate tectonic environment and belonged to the east rock area of Emeishan basalt.关键词
峨眉山玄武岩/岩石地球化学特征/LA-ICP-MS定年/板内玄武岩/威信地区Key words
Emeishan basalt/petrochemical and geochemical characteristics/LA-ICP-MS dating/intraplate flooding basalts/Weixin area!分类
天文与地球科学引用本文复制引用
秦亚,杨启军,吕勇,潘明,山克强..云南威信地区玄武岩的地质地球化学特征及其意义[J].桂林理工大学学报,2018,38(4):625-639,15.基金项目
广西自然科学基金项目(2017GXNSFBA198166 （）
2018GXNSFAA281248) （）
广西科技计划项目(桂科AD16450001) （桂科AD16450001）
中国地质科学院岩溶地质研究所区调项目研究专题(YR-JJHT-2014-492) （YR-JJHT-2014-492）
有色及贵金属隐伏矿床勘查教育部工程研究中心项目(2018GCZX004) （2018GCZX004）
广西高校科研项目(KY2015YB127) （KY2015YB127）
