甘新交界红柳河地区早志留世蛇绿混杂岩的厘定及大地构造意义

地质、岩石化学、地球化学、同位素年代学综合研究证明，红柳河地区蛇绿混杂岩同橄榄岩、辉长岩、玄武岩和弧后火山－沉积岩系组成，玄武质岩石地球化学特征不同于典型大洋中脊，岛弧及板内玄武岩，并暗示其形成于大陆边缘向洋中脊过渡的构造环境，铀－铅同位素测年结果证明其侵位于早志留世，混杂时代早于晚泥盆地，上述成果表明中天山结晶基底与塔里木大陆之间在早志留世曾闰开形成红柳河小洋盆，于晚泥盆世之前发生碰撞混杂形成次级缝合带。

THE CLARIFICATION AND TECTONIC IMPLICATION OF THE EARLY SILURIAN OPHIOLITE MELANGE IN HONGLIUHE AREA

Comprehensive studies of geology,petrochemistry,geochemistry and isotopic chronology revealed that the ophiolite melange in Hongliuhe area consists of peridotite,gabbro,basalt and back arc volcanic and sedimentary rocks.The geochemical characteristics of basalt rock of the Hongliuhe area,which is different from those of normal oceanic ridges,island arcs and intraplates,implied that it was formed in the transitional tectonic environment of continent margin to oceanic ridge.Isotopic dating of U Pb showed that the ophiolite was formed in the early Silurian and the ophiolite melange was induced before late Devonian.Evidence indicated that the Hongliuhe small oceanic basin occurred in the early Siluriaon and separated the Tarim basin and the crystalline basement of Mid Tianshan.The collision of Tarim basin and Mid Tianshan before late Devonian Led to the disappearance of Hongliuhe small oceanic basin and to the formation of ophiolite melange and sub suture zone.