Abstract
The strain geometry, microstructure and metamorphism is described from two minor shear zones from the Chatelaudren metagabbro, N. Brittany. A serially slabbed shear zone reveals a strain geometry consistent with simple shear deformation. Strain calculations based on X trajectory angles coincide with those obtained from elliptical mineral clusters at high values of strain only. Strain profiles typically show a broad low-strain region with a narrow high-strain peak at the centre of the zones. Microstructures typically show distinct grain size reduction in both amphibole and feldspar towards the high strain region of shear zones, and this is discussed in terms of deformation mechanisms related to strain softening. A palaeostress estimate based on recrystallized feldspar grain sizes gives a differential stress of 32 MPa for the low strain region and 119 MPa in the shear zone centre. Electron probe analyses reveal chemical and mineralogical changes accompanying metamorphism within the shear zones. This suggests local conditions favourable for ionic diffusion and the activity of fluids is implied.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
