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大比例尺 (1∶10 0 0 0 )构造制图及构造分析表明 ,碧溪岭地区超高压变质岩石含有丰富的构造演化历史记录。同碰撞或挤压组构只保留于榴辉岩及其它超高压变质岩透镜体内部 ,表现为高角度网络状超高压剪切带与弱应变透镜体域规律组合格式。前者由面理或糜棱岩化榴辉岩组成 ,后者由块状榴辉岩及石榴橄榄岩组成。碰撞期后伸展构造表现为区域性的假单斜状 ,内部呈低缓角度的网络状强应变带及所环绕的透镜状弱应变域组合格式 ,强应变带的岩石为由榴辉岩退变成的角闪岩相高压片麻岩及部分熔融形成的含榴花岗岩 ,透镜状弱应变域的岩石为弱角闪相改造的榴辉岩及石榴橄榄岩。不同尺度上同碰撞或挤压组构及碰撞期后伸展组构所显示的这种残斑基质流变学结构样式 ,虽然与先期原岩成分、结构、流变学的不均一性有关 ,但主要是多期递进应变分解作用的结果 ,支持榴辉岩“原地”成因模式。依据构造学证据和可利用的岩石学及同位素年代学资料 ,分析了超高压变质岩石的形成及折返过程 ,指出碧溪岭地区超高压变质岩石是在 2 45～ 2 10Ma形成的 ,碰撞期后伸展作用主要发生在 2 0 0～ 170Ma。在超高压变质岩石向地壳表层折返过程中 ,张扭作用可能有重要功能 ,不支持碧溪岭地区遭受过多期超高压变质作用的推论。
Large-scale (1:10 0 0) tectonic mapping and tectonic analysis indicate that the UHP metamorphic rocks in Bixiling area have rich tectonic evolution history records. The collisional or squeeze structure only remains in the eclogite and other ultrahigh-pressure metamorphic lens bodies, which is characterized by the combination of high-angle network UHP shear bands with the weakly-distorted lens domain. The former is composed of facial or mylonitic eclogite, which consists of massive eclogite and pomegranate peridotite. After the collision period, the extensional structure showed a regional pseudo- monoclinic shape, a network-like strong strain zone with low-angle inside and a combination of lenticular weak-strain fields surrounded by strong levitation zone. Amphibolite facies and high-pressure gneiss, partly melted gneissic granite and lenticular weak-strain rock are eclogite and pomegranate peridotite altered by weak angle flashover. Although the rheological structure of this kind of remnant matrix displayed by collisions or squeeze structures at different scales and extensional structures after the collision period is related to the heterogeneity of the composition, structure and rheology of the original protoliths, Mainly the result of multi-stage progressive strain decomposition, supporting eclogite “in-situ” genetic models. Based on the tectonic evidence and available petrology and isotopic data, the formation and reenforcement of UHP metamorphic rocks are analyzed. It is pointed out that the UHP metamorphic rocks in Bixiling area were formed during 2 45 ~ 2 10Ma after the collision period Stretching mainly occurs in 200 ~ 170Ma. Tensile twisting may play an important role in the process of UHP metamorphic rocks returning to the crust surface, and does not support the corollary of the Bixiling area suffering from excessive metamorphism of UHP.