Deformation of olivine-spinel aggregates in the system (Mg,Ni)_2GeO_4 deformed to high strain in torsion: Implications for upper mantle anisotropy

摘要

Deformation of mantle phases to high strain is fundamental for understanding mantle dynamics. However, it is technically challenging to perform deformation experiments yielding accurate mechanical results at the high pressures required for certain mantle phases, such as wadsleyite and ringwoodite. Deformation experiments on analog materials of such high-pressure phases can provide insight into the deformation properties of the mantle. The (Mg,Ni)_2GeO_4 system undergoes the olivine-spinel transformation at much lower pressures than the silicate counterpart. Hence the high strain deformation properties of an olivine-spinel rock can be studied at experimentally tractable pressures and temperatures.