Experimental Investigation of Glaucophane Rheology through Shear and Axial Compression Griggs Apparatus Experiments on Hot-Pressed Aggregates

Abstract:

Constraining the rheological properties of glaucophane is critical to understanding subduction zone dynamics. Based on the rock record, glaucophane is a major constituent mineral associated with mafic oceanic crust at blueschist metamorphic facies. Previous experimental work on glaucophane focuses on the deformation of natural polyphase rocks with an emphasis on seismic anisotropy. Here we perform general shear and axial compression deformation experiments on synthetic glaucophane aggregates in a Griggs apparatus. The synthetic aggregates were produced through mineral separation of a natural blueschist from Syros, Greece. After mineral separation, the powders contain ~95% glaucophane with ~5% omphacite and epidote. We will present mechanical and microstructural data from constant displacement and strain-rate stepping experiments with the aim of developing a glaucophane flow law. Our results will also be compared to ongoing experiments focused on the viscous properties of experimentally deformed natural aggregates (see abstract in this conference by Tokle et al.).