Diffusion creep of fine‐grained polycrystalline anorthite at high temperature

Abstract

We performed creep experiments on synthetic fine‐grained polycrystalline anorthite ( d < 30 µm) at temperatures from T = 1000°C to 1300°C, oxygen fugacities of f O2 = 10 −19 –10 −4 MPa, and stresses of σ = 5–80 MPa at room pressure. Experimental results show creep with high strain‐rate sensitivity for stresses below σ < 30 MPa. We found the empirical flow law: Transmission electron microscopy shows that the material is free of melt. The dislocation density is less than 1×10 8 cm −2 . We suggest that the samples deformed in diffusion‐controlled grain size sensitive creep.