A microstructural investigation was carried out on leuco-granodiorite mylonites from the Montalto shear zone (Calabria, southern Italy) exhibiting different stages of deformation. The main mineral assemblage is Qtz, Pl, Kfs Wm, typical of greenschist to lower amphibolite facies conditions in the PT range 0.25– 0.55 GPa and 350–550 °C (Cirrincione et al. 2008; 2009). Occurring minerals display S–C and shear-band textures; mica-fish and ribbon-like quartz are widespread. In particular, we investigated quartz c-axis orientations in selected naturally sheared rocks by different techniques spanning from the classical universal stage (US), a computer aided polarization microscopy method (CIP), the time-of-flight (TOF) neutron diffraction analysis, and the electron backscatter diffraction (EBSD). Comparison among results obtained by different techniques give on the whole a good correlation, nevertheless we can conclude that each method provides complementary piece of information (Fazio et al., 2017) that are important for specific structural interpretations. Moreover, by means of shape porphyroclasts analysis, a sub-simple shear (40% simple shear vs 60% pure shear) was also inferred and a general tendency of an asymmetric cmaximum near to the Z direction (normal to foliation) suggesting dominant basal slip, consistent with fabric patterns related to dynamically recrystallization under greenschist facies, was recognized.
|Titolo:||Quartz CPO analysis of mylonitic leuco-granodiorites from a ductile crustal scale shear zone (Calabria, southern Italy)|
FAZIO, EUGENIO (Corresponding)
PUNTURO, Rosalda (Corresponding)
|Data di pubblicazione:||2017|
|Appare nelle tipologie:||4.3 Poster|