What brought them up? Exhumation of the Dabie Shan ultrahigh-pressure rocks

摘要: Metamorphic coesite and diamond in the Dabie Shan, eastern China, testify to subduction of continental crust >100 km depth. Exhumation these ultrahigh-pressure rocks through encompassed two stages. (1) South-dipping foliation, southeast-plunging stretching lineation, lineation-parallel isoclinal folds, boudins indicate extreme subhorizontal shortening subvertical extension during top-to-northwest shearing at 200–180 Ma. Syntectonic recrystallization occurred eclogite amphibolite facies temperatures pressures below stability. (2) Northwest-southeast from 133 122 Ma was concentrated within an asymmetric structural dome a magmatic complex that forms northern half Shan. Pluton cores deep levels have weak hypersolidus fabrics, pluton carapaces are mylonitic gneisses formed upper conditions. Deformation is greenschist mylonites ultramylonites along Xiaotian-Mozitang detachment fault topographic limit Our preferred exhumation model involves stages: Triassic indentation—vertical extrusion erosion—followed by Cretaceous plate margin transtension.