JOURNAL CLUB DO DEPARTAMENTO DE FÍSICA DOS MATERIAIS E MECÂNICA – FMT
Nesta semana o pós-graduando Michel Lacerda Marcondes dos Santos, do Grupo Teórico de Materiais, apresentará o artigo: “Shear Deformation Ofbridgmanite and Magnesiowüstiteaggregatesat Lower Mantle Conditions” – Jennifer Girard, George Amulele,* Robert Farla,† Anwar Mohiuddin, Shun-ichiro Karato‡
Dia: 24 de maio, terça-feira, às 12h10
Local: Sala de Seminários José Roberto Leite Ed. Alessandro Volta (bloco C) – Sala 110, IFUSP
Abstract:
Rheological properties of the lower mantle have strong influence on the dynamics and evolution of Earth. By using the improved methods of quantitative deformation experiments at high pressures and temperatures, we deformed a mixture of bridgmanite and magnesiowüstite under the shallow lower mantle conditions.We conducted experiments up to about 100% strain at a strain rate of about 3×10−5 second−1 . We found that bridgmanite is substantially stronger than magnesiowüstite and that magnesiowüstite largely accommodates the strain. Our results suggest that strain weakening and resultant shear localization likely occur in the lower mantle. This would explain the preservation of long-lived geochemical reservoirs and the lack of seismic anisotropy in the majority of the lower mantle except the boundary layers.
