a càrrec d'Ernest Rutter, School of Earth Sciences, University of Manchester, Manchester, Anglaterra
SEMINARIS DE LA FACULTAT DE GEOLOGIA I L'INSTITUT DE CIÈNCIES DE LA TERRA "JAUME ALMERA"

Universitat de Barcelona (UB)
Consell Superior d'Investigacions Científiques (CSIC)

Dia: Dimarts, 13 de maig
Hora: 12:00 h.
Lloc: Sala d'actes de l'Institut "Jaume Almera"

Resum: It is widely recognized that metamorphic reactions in nature facilitate deformation. Unfortunately, during prograde metamorphism, textural and mineralogical equilibration under conditions of rising temperature and relaxation of stress tends to remove microstructural evidence of the nature of the mechanics of the interaction. However, we can study certain interactions through laboratory experiments. Lizardite serpentinite is particularly well suited because it dehydrates rapidly at ca 500 C to olivine + talc + water. This affects the mechanical properties in 3 ways: (i) under undrained conditions causing embrittlement and weakening through the generation of high pore pressure, (ii) under drained conditions (controlled pore pressure) through the formation of transiently fine grained reaction products that favour flow by grain-size sensitive processes, (iii) through the formation of collapsible porosity owing to the smaller specific volumes of the solid product phases, favour
The experimental data can be used to infer creep and seismogenic behaviour of dehydrating serpentinite in subduction zones, and in transform fault zones, and also has implications for general relationships between deformation and metamorphism.