西天山异剥钙榴岩的地球化学研究  

Geochemistry of rodingite derived from eclogite in western Tianshan,China.

作　　者：李旭平[1] 张立飞[2] 王泽利[3] 

机构地区：[1]山东科技大学 地质科学与工程学院,青岛266510 [2]北京大学地球与空间科学学院,北京100871 [3]山东科技大学地质科学与工程学院,青岛266510

出　　处：《岩石学报》2008年第4期711-717,共7页Acta Petrologica Sinica

基　　金：国家自然科学基金(40372034);(40730314)的资助.

摘　　要：西天山长阿吾子的蛇绿混杂岩带的超基性岩及其伴生岩石异剥钙榴岩位于伊犁中天山板块和塔里木板块碰撞造山带。微量元素特征表明退变榴辉岩原岩成因与俯冲带环境有关。异剥钙榴岩中稀土元素和微量元素全面、大幅度降低,反映出来自于蛇纹岩化,作用于异剥钙榴岩化流体的强大的淋滤作用。因而异剥钙榴岩的稀土和微量元素特征都不能反映原始岩浆的特点,无法据此推断原始岩浆产生的大地构造环境。对退变榴辉岩的主元素和微量元素稀土元素的研究表明,长阿吾子异剥钙榴岩的原岩钙碱性玄武岩可能形成于俯冲上板片(SSZ)的岛弧环境。Rodingite associated with ultramafic complex of Weastern Tianshan is located in orogenic belt between the Tarim plate and the Yili-central Tianshan craton. Tianshan rodingite is formed from eclogite included in the uhramafic rock of the Changawuzi ophiolites in the Southwestern Tianshan ophiolitic melange. The features of major, trace and rare elements of retrograded eclogites exhibit that protolithic eclogite of the Tianshan rodingite is formed in the subduction zone, Full-scale decreases of REE and trace elements in rodingite reflect a powerful leaching process during severe serpentinization and rodingitization. Characteristics of REE and trace elements in rodingite, therefore, can not imply the formation condition of primary magma, and to deduce geological background, Whereas geochemical investigations of retrograde eclogite in western Tianshan indicate that the protolithic basalt of Changawuzi rodingite probably forms in a super subduction zone environment.

关 键 词：西天山 异剥钙榴岩 退变榴辉岩 地球化学 

分 类 号：P588.323[天文地球—岩石学] P578.954[天文地球—地质学]