Investigation of Internal Stresses and Strains Induced by the Olivine-Spinel Transformation: Mechanical Models and Microstructural Observations

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9706289 Burnley The goal of this investigation is to develop improved mechanical models of the internal stresses and strains caused by nucleation and growth of dense transition zone phases, wadsleyite and ringwoodite, in olivine. There is much evidence to argue that the mechanical response of the host olivine influences kinetics and fabric development during transformation. These mechanical effects should be most profound in low temperature environments within subducting lithospheric slabs where olivine is relatively strong. Phase transformation and the resulting metamorphic fabrics it produces can have a strong influence on the behavior of a subducting slab because transformation in the slab determines its relative buoyancy as well as its strength. The PIs will develop numerical models of the mechanical interactions between parent and daughter phases during transformation, guided by observations of experimentally produced transformation microstructures collected over a wide range of pressure, temperature and stress conditions. ***