地质学报2012，Vol.86Issue(1)：188-197,10.DOI:11-1951/P.20120104.1640.003
西准噶尔巴尔雷克蛇绿混杂岩带中玄武岩地球化学特征及大地构造意义
Geochemistry of Basalt from the Barleik Ophiolitic Mélange in West Junggar and its Tectonic Implications
摘要
Abstract
Basalts from the Barleik ophiolitic melange in West Junggar occur with serpentinite, radiolarian chert,and muddy siltstone and tuff from the Late Devonian Tielieketi Formation. Detailed geochemical analyses show that the basalts have typical geochemical characteristics to those of OIB, with low SiO2(42. 15%~ 44.71%), highTiO2(3.17%~3. 77%), Na2O (1. 73%~2. 28%), low A12O3(13. 54%~14. 31%), K2O (1%~1.82%) and moderate MgO (6. 75%~8.14%, Mg~# =43~46). The REE distribution patterns are similar to those of OIB, with 2REE=186×10-6~219. 06×40-6, LREE enrichment ((La/Yb)N = 11. 37 ~12. 62), weak Eu negative anomaly (Eu/Eu* =0. 96~1), high Ti/Yb and Zr/Yb ratios (7395~8724, 120~136, respectively). Comprehensive study also suggests that the basalts formed in an ocean island or a seamount setting, with the magma originating from EMI - type enriched mantle, I. E. Upwelling of asthenosphere resulted in partial melting of a large amount of spinel lherzolite mantle and thus forming the basalt. Regionally, the Devonian oceanic basin which is represented by the basalts of the Barleik ophiolitic melange occurs as a remnant oceanic basin formed by northward shrinking of the West Junggar Paleoceanic Basin.关键词
洋岛玄武岩(OIB)/巴尔雷克蛇绿混杂岩/地球化学/古洋盆/西准噶尔Key words
ocean island basalt (OIB)/ Barleik ophiolitic melange/ geochemistry/ paleoceanic basin/West Junggar引用本文复制引用
杨高学,李永军,杨宝凯,王海博,张洪伟,佟丽莉..西准噶尔巴尔雷克蛇绿混杂岩带中玄武岩地球化学特征及大地构造意义[J].地质学报,2012,86(1):188-197,10.基金项目
本文为中央高校基本科研业务费专项资金(编号CHD2010ZY005)与国土资源大调查项目(编号XJZBKD2008-04,XJQDZ2009-03)资助的成果. （编号CHD2010ZY005）
