地质学报2013，Vol.87Issue(3)：343-352,10.
西准噶尔巴尔雷克-带石炭系黑山头组火山岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及构造环境
LA-ICP-MS Zircon U-Pb Age, Geochemistry and Tectonic Setting of the Volcanic Rocks in the Heishantou Formation from the Area of Barleik, West Junggar
摘要
Abstract
The volcanic rocks of the Heishantou Formation in the area of Barleik, West Junggar, consist of gray purple (vesicular) almond andesite and almond shaped basaltic andesite, belonging to sub-alkaline series. High-precision LA-ICP-MS zircon U-Pb dating shows that the rocks formed at the age of 349 8Ma, with MSWD=0. 14 (95% conf.), suggesting an age of Early Carboniferous. These rocks are characterized by moderate Mg* (23. 82—50. 4) , relatively high alkali (Na2O+K2O=3. 74% ~8. 02%), and relative enrichment in Na, enrichment in LREE [(La/Yb)N = 2. 87~13. 41] and well fractionated [(La/Sm)N = 1. 46 ~ 3. 41], and weak HREE fractionation [(Gd/Yb)N = l. 46~3. 48]. Only part of the samples shows weak negative Eu anomalies (δEu = 0. 82 — 1. 47). Large ion lithophile elements (LILEs, eg. , Ba, Th, K and Sr) are relatively enriched, especially Ba and K, and high field-strength elements (HFSEs, eg. , Nb, Ta , and Ti) are depleted, but Zr and Hf slightly enriched. Geochemical features indicate that the volcanic rocks are the products of metasomatism between subduction-zone fluids and lithospheric mantle. Comprehensive analysis indicates that the volcanic rocks derived from active continental margin. The determination of the age and tectonic environment information of volcanic rocks from the Heishantou Formation provides new evidence for further understanding of the tectonic evolution in the area of Barleik in West Junggar.关键词
锆石LA-ICP-MS U-Pb测年/地球化学/构造环境/火山岩/西准噶尔Key words
zircon LA-ICP-MS U-Pb age/ geochemistry/ tectonic setting/ volcanic rocks/ West Junggar引用本文复制引用
田陟贤,阎军,李永军,杨高学,田猛,佟丽莉,严镜..西准噶尔巴尔雷克-带石炭系黑山头组火山岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及构造环境[J].地质学报,2013,87(3):343-352,10.基金项目
本文为国土资源大调查项目(编号 XJZBKD2008-04)资助的成果. （编号 XJZBKD2008-04）
