10 research outputs found
Dauphiné twinning and texture memory in polycrystalline quartz
Mechanical twinning in polycrystalline quartz was investigated in situ with time-of-flight neutron diffraction and a strain diffractometer. Dauphine´ twinning is
highly temperature sensitive. It initiates at a macroscopic differential stress of 50–100 MPa and, at 500C, saturates at 400 MPa. From normalized diffraction intensities the
patterns of preferred orientation (or texture) can be inferred. They indicate a partial reversal of twinning during unloading. The remaining twins impose residual stresses corresponding to elastic strains of 300–400 microstrain.
Progressive twinning on loading and reversal during unloading, as well as the temperature dependence, can be reproduced with finite element model simulations
Mechanisms of fine extinction band development in vein quartz: new insights from correlative light and electron microscopy
Petrological Modifications in Continental Target Rocks from Terrestrial Impact Structures: Evidence from Cathodoluminescence
A ductile extensional shear zone at the contact area between HP-LT metamorphic units in the Talea Ori, central Crete, Greece: deformation during early stages of exhumation from peak metamorphic conditions
Ultrafast Imaging of Laser Driven Shock Waves using Betatron X-rays from a Laser Wakefield Accelerator
The south-western Black Forest and the Upper Rhine Graben Main Border Fault : thermal history and hydrothermal fluid flow
The thermal history of the south-westernmost Black Forest (Germany) and the adjacent Upper Rhine Graben were constrained by a combination of apatite and zircon fission-track (FT) and microstructural analyses. After intrusion of Palaeozoic granitic plutons in the Black Forest, the thermal regime of the studied area re-equilibrated during the Late Permian and the Mesozoic, interrupted by enhanced hydrothermal activity during the Jurassic. At the eastern flank of the Upper Rhine Graben along the Main Border Fault the analysed samples show microstructural characteristics related to repeated tectonic and hydrothermal activities. The integration of microstructural observations of the cataclastic fault gouge with the FT data identifies the existence of repeated tectonic-related fluid flow events characterised by different thermal conditions. The older took place during the Variscan and/or Mesozoic time at temperatures lower than 280A degrees C, whereas the younger was probably contemporary with the Cenozoic rifting of the Upper Rhine Graben at temperatures not higher than 150A degrees C