The Qinling orogenic belt is a collision zone between the North China and Yangtze cratons. The Qinling Complex is a Precambrian metamorphic complex, developed in the inner zone of the orogenic belt , which records the...The Qinling orogenic belt is a collision zone between the North China and Yangtze cratons. The Qinling Complex is a Precambrian metamorphic complex, developed in the inner zone of the orogenic belt , which records the metamorphic and deformational history and PTt path of the regional meta-morphism of the collision zone . The present paper studies the metamorphic and deformational history and the PTt path of various tectono-metamorphic cycles in order to describe the geodynamic processes prevailing in that part of the Qinling orogenic belt since Proterozoic.The tectonometamorphic history and evolution of the Qinling Complex is divided into two stages: the stage of formation and the stage of modification During the stage of formation dated as Proterozoic,three deformational sequences are recognized. The amphibolite facies regional metamorphism is earlier than or synchronous with the first or second phase of folding. Three metamorphic zones, i.e. And-Ms ,Sil- Ms, Sil Kfs are delimited. During the stage of modification , the emplacement of Caledonian granite , superimposed thermal aureole (garnet K feldspar zone )and the development of ductile shear zones are major events.Metamorphic reactions are reconstructed in terms of analysis of re-equilibrium textures. Geothermobarometric calculations are conducted to calibrate the PT conditions of metamorphism .The metamorphic PTt paths have been estabh'shed. The PTt path of the Proterozoic tectonometamorphic cycle shows a clockwise pattern and is characterized by prominent decompression. The PTt path of the Caledonian tectonometamorphic cycle is characterized first by PT rising ,then isothermal decompression (rapid uplift), and finally by isobaric cooling The PTt path of the two tectonometamorphic cycles evidence the geodynamic processes: two major stages of collision and uplift in the Proterozoic and Caledonian Hercynian periods, respectively, during the evolution of Qinling orogenic belt.展开更多
A new kind of structural model, the constrained lateral extrusion, is presented based on the study of the Jurassic deformation style, combinatory pattern of several structural belts and the prototype basin development...A new kind of structural model, the constrained lateral extrusion, is presented based on the study of the Jurassic deformation style, combinatory pattern of several structural belts and the prototype basin development in western Ordos basin and its adjacent regions. The constitution,material movement and geodynamical process of the structural model are proposed. The formation mechanism and genetic relation between structural belts and prototype basins are fully studied.展开更多
文摘The Qinling orogenic belt is a collision zone between the North China and Yangtze cratons. The Qinling Complex is a Precambrian metamorphic complex, developed in the inner zone of the orogenic belt , which records the metamorphic and deformational history and PTt path of the regional meta-morphism of the collision zone . The present paper studies the metamorphic and deformational history and the PTt path of various tectono-metamorphic cycles in order to describe the geodynamic processes prevailing in that part of the Qinling orogenic belt since Proterozoic.The tectonometamorphic history and evolution of the Qinling Complex is divided into two stages: the stage of formation and the stage of modification During the stage of formation dated as Proterozoic,three deformational sequences are recognized. The amphibolite facies regional metamorphism is earlier than or synchronous with the first or second phase of folding. Three metamorphic zones, i.e. And-Ms ,Sil- Ms, Sil Kfs are delimited. During the stage of modification , the emplacement of Caledonian granite , superimposed thermal aureole (garnet K feldspar zone )and the development of ductile shear zones are major events.Metamorphic reactions are reconstructed in terms of analysis of re-equilibrium textures. Geothermobarometric calculations are conducted to calibrate the PT conditions of metamorphism .The metamorphic PTt paths have been estabh'shed. The PTt path of the Proterozoic tectonometamorphic cycle shows a clockwise pattern and is characterized by prominent decompression. The PTt path of the Caledonian tectonometamorphic cycle is characterized first by PT rising ,then isothermal decompression (rapid uplift), and finally by isobaric cooling The PTt path of the two tectonometamorphic cycles evidence the geodynamic processes: two major stages of collision and uplift in the Proterozoic and Caledonian Hercynian periods, respectively, during the evolution of Qinling orogenic belt.
文摘A new kind of structural model, the constrained lateral extrusion, is presented based on the study of the Jurassic deformation style, combinatory pattern of several structural belts and the prototype basin development in western Ordos basin and its adjacent regions. The constitution,material movement and geodynamical process of the structural model are proposed. The formation mechanism and genetic relation between structural belts and prototype basins are fully studied.
