摘要
阿拉塔格花岗岩分布于东天山加里东造山带内的弧后盆地蛇绿岩套中,地质剖面自下而上为超镁铁质岩、镁铁质岩、中性岩和斜长花岗岩。各岩相之间呈渐变过渡关系。岩石学、岩石化学和稀土元素特征以及与其它地区典型幔源型花岗岩特征的对比表明阿拉塔格花岗岩属于幔源型,它代表着弧后盆地蛇绿岩序列内部分异作用末期的产物。
The Arlatager granite is found in the back-arc basin ophiolite of the East Tianshan Caledonian trench-arc-basin fold belt. the igneous body, from bottom to top, consists of ultramafic, mafic, intermediate rocks and plagiogranite. Contact relations between the above rock types are transitional. The chemical compositions of the plagiogranite are SiO_2 67.30～67.41％, Al_2O_3 14.74～16.06％, K_2O+Na_2O 5.02～5.71％, K_2O/Na_2O ratio 0.15～0.22. The REE content in the plagiogranite is 11.26～54.53ppm, the LREE/HREE ratio varies in 7.66～15.56ppm, and the Eu/EU~*=1.36～7.5. The distinctive positive europium anomolies are thought to have been derived from the removal of Eu-depleted gabbro and hornblendite from the parent basaltic melt. Compared with the Troodos, Bendong and Xiqiu mantle-derived granites, the Arlatager granite has almost the same characteristics with respect to geological background, rock assemblage, petrology and petrochemistry except the REE content and the REE distribution patterns. It seems clear that the Arlatager granite is also mantle-derived and likely to represent the end product of differentiation within the ophiolite sequences.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1992年第2期201-204,共4页
Acta Petrologica Sinica
基金
国家"七五"攻关305项目研究课题
关键词
加里东造山带
长花岗岩
花岗岩
East Tianshan
Caledonian fold belt
Plagiogranite
