10:15 〜 10:30
[SCG50-06] Brittle behavior of Lawsonite under the conditions of cold subduction zone
★Invited Papers
One of the causes for intermediate-depth earthquakes (50-300 km) in subducting slabs has been proposed to be the dehydration embrittlement (e.g., Raleigh and Paterson, 1965) because there are many kinds of hydrous minerals in a subducting slab and hypocenter distribution coincides with the dehydration boundary determined by high pressure experiments (e.g., Hacker et al., 2003). Lawsonite is one of the candidates for dehydration embrittlement in cold subducting slabs, however, there are few previous experimental works.
So, we conducted deformation experiments on lawsonite at pressures of 2.5 to 6 GPa and temperatures of 300 °C to 800 °C, to clarify the deformation property of lawsonite and understand the relationship between dehydration and brittle failure. Experiments were carried out using Deformation-Cubic Anvil Press (D-CAP) installed at KEK PF AR-NE7A beamline. Pure lawsonite powder (~ 98%) was used as starting material.
Our results indicate that unstable fault slip did not occur during the dehydration of lawsonite. Instead, we find that deformation was localized and weakening occurred within the stability field of lawsonite. We can show that lawsonite can exhibit localized deformation in the absence of dehydration. We will discuss the deformation property of lawsonite (mechanical data and microstructures) and the possibility of the candidate for dehydration embrittlement in cold subducting slabs.
So, we conducted deformation experiments on lawsonite at pressures of 2.5 to 6 GPa and temperatures of 300 °C to 800 °C, to clarify the deformation property of lawsonite and understand the relationship between dehydration and brittle failure. Experiments were carried out using Deformation-Cubic Anvil Press (D-CAP) installed at KEK PF AR-NE7A beamline. Pure lawsonite powder (~ 98%) was used as starting material.
Our results indicate that unstable fault slip did not occur during the dehydration of lawsonite. Instead, we find that deformation was localized and weakening occurred within the stability field of lawsonite. We can show that lawsonite can exhibit localized deformation in the absence of dehydration. We will discuss the deformation property of lawsonite (mechanical data and microstructures) and the possibility of the candidate for dehydration embrittlement in cold subducting slabs.