大别山晓天—磨子潭断裂带石英脉流体包裹体的特征及其构造意义

晓天—磨子潭断裂流体包裹体的均一温度、盐度和捕俘压力研究结果表明:晓天—磨子潭断裂中石英脉中流体主要来自浅部,有多期次流体包裹体,流体包裹体的均一温度分为三个区间:140～180℃、190～240℃和270～340℃,反映了至少经历了三次强烈的流体活动。流体包裹体的盐度<10%,捕获压力<1.350×108Pa。总体上越靠近晓天—磨子潭断裂,包裹体的均一温度和盐度越高,捕获压力越大,局部地区的差异,能从断裂对流体控制上得到合理的解释;另外,流体包裹体的均一温度、盐度和捕获压力,在不同的显微构造,围岩性质、构造环境和时空范围中,发生不同的变化。一方面多次构造活动和热事件的驱动流体活动,另一方面流体的活动,降低了岩石脆—韧性变形的温压条件,促进了岩石的变形。

CHARACTERISTICS OF FLUID INCLUSIONS IN QUARTZ VEINS IN XIAO TIAN-MOZITAN FAULT AND THE TECTONIC IMPLICATIONS

Based on the research of the homogeni zation temperature,salinity and tr ap pressure of the fluid inclusions in quartz veins in the Xia otian-Mozitan fault of the Dabie oro genic belt,it explicates that the fluid originates from the surface.Homogenization temperature mainly can be d ivided into three scopes:140-180℃,190-240℃and 290-340℃,the salin ity is less than 10%and the trap press ure less than 1.35×10 8 Pa.Generally,the more near the samp le next to the fault,the higher the homogenization temperature,salinit y and trap pressure,except for a few sa mples in some sections.That implies the fluid is mainly controlled by the fault,as well as affected by the t ectonic activities in some sections.Additionally,the homogenization temperature,salinity and trap pressure of inclusions change in the diff erent lithologic character,wall ro cks,structure environment and space-time progress.The fluid is active with the driving of tectonic activities a nd tectonic thermal events;on the other hand,the fluid activities reduce t he temperture and pressure conditio n of brittle-ductile deformation and make the rock deform fast.