The sub-vertical meso-and micro-structures and fabrics developed in coesite-bearing foliated eclogites in the Taohang （桃行） area, southeastern Shandong （山东）, China. The diagnostic structures and fabrics, includ...The sub-vertical meso-and micro-structures and fabrics developed in coesite-bearing foliated eclogites in the Taohang （桃行） area, southeastern Shandong （山东）, China. The diagnostic structures and fabrics, including penetrative foliation or mylonitic foliation containing mineral and stretching lineations, as well as sheath-like folds, appear to be the development of anastomosing UHP eciogite-facies shear belt arrays hosting massive eelogites. Textural relationships and mineral assem-blages indicate that the deformation of foliated eclogites developed closely after the formation of the massive eclogite, prior to the development of the granulite/amphibolite-facies symplectites and coronas, occurring over a very wide pressure range of （31-8）×10^2 MPa. It presents the structural records of the tectonometamorphic processes as being responsible for the earliest stages of exhumation of the UHP metamorphic rocks. Extensive regional field observations show that the meso-and micro-structures and fabrics recognized in the foliated eclogites at Taohang are remarkably similar or consistent in the whole Dabie （大别）-Sulu （苏鲁） UHP metamorphic belt. This article, thus, supports the idea that the earliest stages of exhumation of the UHP metamorphic rocks, from mantle depths to the Moho or the mantle-crust boundary layering, may be attributed mainly to a sub-vertical extrusion and ductile flow along the subduction channel, belonging to a syn-collision exhumation at about 235 to 220 Ma.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 40372094 and 49972067)
文摘The sub-vertical meso-and micro-structures and fabrics developed in coesite-bearing foliated eclogites in the Taohang （桃行） area, southeastern Shandong （山东）, China. The diagnostic structures and fabrics, including penetrative foliation or mylonitic foliation containing mineral and stretching lineations, as well as sheath-like folds, appear to be the development of anastomosing UHP eciogite-facies shear belt arrays hosting massive eelogites. Textural relationships and mineral assem-blages indicate that the deformation of foliated eclogites developed closely after the formation of the massive eclogite, prior to the development of the granulite/amphibolite-facies symplectites and coronas, occurring over a very wide pressure range of （31-8）×10^2 MPa. It presents the structural records of the tectonometamorphic processes as being responsible for the earliest stages of exhumation of the UHP metamorphic rocks. Extensive regional field observations show that the meso-and micro-structures and fabrics recognized in the foliated eclogites at Taohang are remarkably similar or consistent in the whole Dabie （大别）-Sulu （苏鲁） UHP metamorphic belt. This article, thus, supports the idea that the earliest stages of exhumation of the UHP metamorphic rocks, from mantle depths to the Moho or the mantle-crust boundary layering, may be attributed mainly to a sub-vertical extrusion and ductile flow along the subduction channel, belonging to a syn-collision exhumation at about 235 to 220 Ma.
