东秦岭回龙湾强应变带及其地质意义

东秦岭二郎坪群和石界河群之间发现了一条强应变带（称之为回龙湾强应变带），呈ＮＮＷ—ＳＳＥ向延伸，面理置换强烈，韧性剪切变形特征明显，糜棱岩发育。该强应变带的发现表明，二郎坪群和石界河群之间既非不整合接触，也不是整合接触，而是断层接触关系。结合原岩建造、沉积环境和变质作用特征，作者认为二郎坪群和石界河群之间并非简单的地层学上的上下关系，而是两个近乎同时异地的变质地质体。

HUILONGWAN STRONG STRAIN BAND AND ITS GEOLOGICAL MEANING IN THE EAST QINLING

A strong strain band extended in NNW-SSE direction between the Erlangping Group and Shijiehe Group was discovered in the East Qinling Mt. in central China (we call it Huilongwan strong strain band). This article mainly discusses the dynamic features and the tectonic evolution of the band. There are the strong foliation replacement, district ductile shear deformation and developed mylonite in this strong strain band. The discovery of the strong strain band indicate that the contact relation between the Erlangping Group and Shijiehe Group is neither unconformity nor conformable contact as some geologists suggested in the past. The fact of the contact relation is a fault zone. According to the characteristics of protolyte formation, sedimentary environments and metamorphism, the authors have considered that the two groups are not the closed units of the general stratigrphy, but are two little short of being synchronous heterochthonous different metamorphic terrain without direct relationship.