摘要
位于东大别山北缘的姚河岩体是最近确定的中侏罗世石英二长岩体，角闪石４０Ａｒ３９Ａｒ法定年为１５５．８Ｍａ，用角闪石压力计法得出结晶压力为（２．６５±０．５）×１０２ＭＰａ，结晶定位深度约９ｋｍ。岩体北缘发育的ＮＥ倾的糜棱岩带是磨子潭晓天断裂韧性剪切的结果。对剪切带中宏观标志及显微、超显微构造研究表明，该断裂自中侏罗世之后主要表现为上盘向ＮＥ方向下滑的正断层，两盘垂直差异隆升达９ｋｍ。结合区域构造及深部资料分析显示，东大别造山带并不具有“翻花状”双侧造山链特点。
The Yaohe pluton, found at the northeastern margin of the Dabie mountain recently, is a quartz diorite intrusive body. A precise 40 Ar/ 39 Ar hornblende dating age demonstrates that it had emplaecd in middle Jurassic (155.8Ma). The aluminum in hornblende geobarometer analysis indicates the crystallization pressure of this pluton is about (2.65±0.5)×10 5Pa,and its emplaced depth is about 9km. Mylonite zone in the northern margin of the Yaohe pluton, those foliations dipping to NE direction, is the resultant of ductile shearing by the Mozitan Xiaotian fault. Macrostructures and micro ultramicrostructures in this ductile shear zone show the hanging wall of this normal fault moves down to NE direction, and the vertical difference uplift between two fault walls reaches to 9km. Combined with regional and deep structures, our study shows that eastern Diabie orogen does not possess “flowered” structure.
出处
《地震地质》
EI
CSCD
北大核心
1998年第4期305-311,共7页
Seismology and Geology
基金
国家自然科学基金
关键词
糜棱岩
剪切带
正断层
大别山
岩体
Mylonite, Shear zone, Normal fault, Dabie mountain
