Fluid-rock interaction deduced from geological time bright-layer in the middle crust

在低p /T变质岩中发现了地质时代亮层。发现硅化岩呈层状或透镜状分布，在构造垂向厚度范围内受限于绿岩相条件。与片岩高角度相交的石英脉优先发育。石英脉的赋存模式表明硅化岩相对于下伏岩具有较强的赋存能力。具有高能力对比的岩石边界可能是地震波的良好反射体。如果硅化岩层在地壳深部分布较多，则本研究观测到的中地壳亮层反射将引起中地壳亮层反射。

The geological time bright-layer was recognized in the low-P/T metamorphic rocks. We found that silicified rocks distribute as layers or lenticular bodies, and they are restricted in the greenscist facies conditions within structurally vertical thickness. Quartz veins crossing high-angles with schistosity were preferentially developed. The mode of occurrences of quartz veins indicates that silicified rocks are competent relative to underlying rocks. Rock boundary with high competence contrast is probably a good reflector of seismic waves. Seismic bright-layer reflections in the middle crust would be arisen from observed silicified rock layers in this study, if those are distributed in the deep crust to a considerable extent.