An experimental study of shear deformation and mineral composition changes of granite under the condition of high temperature and high pressure

The fluid-controlling mineralization mechanism during tectonic deformation is a worldwide research focus.In order to comprehend the behavior and role of shear tectonic stress and fluids in the process of tectonic diagenesis and mineralization, it is the key to study the mechanical-chemical effects in the shear deformation process.In this study, the authors analyzed the distribution of mineral reaction and the change of chemical composition caused by the mineral reaction in experimental deformed granite samples under the condition of high temperature and high pressure and discussed interaction between mineral reactions and deformation.The results indicate that plagioclase, k-feldspar and pyroxene can endure brittle-plastic deformation, while most of the quartz and mica display plastic deformation.The hydrolysis of K-feldspar and pyroxene due to the fluid-rock interaction is the most characteristic reaction in the minerals.The strain localization dominantly controls the overall deformation in the experiment.With the strengthening of shear deformation, the brittle fracture gradually forms and develops into cracks.Thus the stress is released, and metal elements are filled along the cracks.These microscopic characteristics are common in the experimental samples, similar to features of the vein in the field.This experiment provides experimental data for the rheological behavior, chemical behavior and shearing process of the ductile shear zone.