红柳河蛇绿岩伸展变形构造与南天山洋盆演化过程研究

There are different types of the spreading structures in the Hongliuhe (HLH) ophiolite, for example, ECC, small low-angle normal fault, conjugated-normal fault, horst-graben, A-type fold and gabric mylonites et al. The tectonic level is from ductile deformation, through ductile-brittle deformation to the brittle deformation. The line and foliation measurements show that there are great differences between the extensional structures of the ophiolite and its boundary zones, they also imply that the extensional deformation underwent brfore close of the oceanic crust. The hornblende Ar-Ar dating results from the gabric mylonite show that the oceanic crust spreading took place at 450-500Ma, while the biotite Ar-Ar ages suggest the oceanic crust was closed at 350-400Ma.

造山带中的蛇绿岩常保留有洋盆扩张过程中伸展变形的构造痕迹。本项目研究南天山东段红柳河蛇绿岩中辉长质糜棱岩和伸展褶劈理等变形构造，恢复其侵位前扩张构造发育特征及规模，分别确定古洋盆生成、扩张拆离和闭合的构造时段，讨论南天山洋盆的性质和构造演化历史，建立古南天山洋构造演化模型。为进一步分析天山造山动力学提供理论依据。