新疆甘肃交界红柳河蛇绿岩中伸展构造与古洋盆演化过程

红柳河蛇绿岩中保存了大量伸展特征构造，如堆晶辉长岩层中发育丰富的辉长质糜棱面理、伸展褶劈理、小型韧性低角度正断层、韧-脆性共轭正断层和脆性正断层等伸展变形构造。蛇绿岩中伸展变形构造经历了完整的变形序列：从韧性变形、经韧脆性变形到脆性变形。构造几何学关系表明这些构造形成于红柳河古洋盆闭合之前洋壳扩张过程中。^40Ar／^39Ar年代学的研究确定了红柳河古洋盆演化的过程：洋盆扩张发育在462Ma之前，并在412Ma前闭合。

The tectonic evolution of the south Tianshan paleo-oceanic crust inferred from the spreading structures and Ar-Ar dating of the Hongliuhe ophiolite, NW China

The Hongliuhe(HLH)ophiolite is the fragment of the Paleozoic south Tianshan oceanic crust.Abundant spreading structures,for example,mylonitic foliations,extensional crenulation cleavages,small low-angle normal faults and brittle conjugated high-angle normal faults were developed in the cumulate gabbroic layer of HLH ophiolite.These extensional structures underwent the integrated processes from ductile deformation,through ductile-brittle deformation to brittle deformation.The geometric studies of the spreading structures indicate they were formed in the sea-floor spreading environment of the paleo-oceanic crust.The ~(40)Ar/~(39)Ar ages propose the sea-floor spreading of the Paleo-south Tianshan oceanic crust was prior to 462Ma and the emplacement of the HLH ophiolite was no later than 412Ma.