JpGU-AGU Joint Meeting 2020

Presentation information

[J] Oral

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG69] Rheology, fracture and friction in Earth and planetary sciences

convener:Miki Tasaka(Shizuoka University), Osamu Kuwano(Japan Agency for Marine-Earth Science and Technology), Ichiko Shimizu(Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University), Shintaro Azuma(Department of Earth and Planetary Sciences, School of Science, Tokyo Institute of Technology)

[SCG69-01] Torsional deformation experiments at Mbar pressures toward understanding deep Earth rheology

★Invited Papers

*Ryuichi Nomura1, Shintaro Azuma2, Kentaro Uesugi3, Yu Nishihara4, Tetsuo Irifune4 (1.Kyoto University, 2.Tokyo Institute of Technology, 3.SPring-8/ JASRI, 4.Ehime University)

Keywords:high-pressure and high-temperature, rotational diamond anvil cell, Earth's deep interior

The rheological properties of deep Earth materials are key to understanding the dynamics and evolution of the Earth’s interior. Recent technological developments in deformation experiments under high pressures and temperatures combined with the use of synchrotron X-rays have facilitated a qualitative understanding of the rheological properties. For instance, through the use of the D-DIA and the rotational Drickamer apparatuses, it is possible to determine stress-strain relationships at high pressures (P) and temperatures (T) to those in the uppermost part of the lower mantle[Girard et al., 2016; Tsujino et al., 2016].

In this study, we introduced a rotational diamond anvil cell [Blank et al., 1984] to extend the pressure range of large-strain steady-state deformation experiments. High experimental pressures covering those in the whole of the lower mantle were achieved using nano-polycrystalline diamond as the anvil material with a high experimental success rate [Nomura et al., 2017]. Additionally, pressures up to multi-Mbar were observed using single crystal diamond anvils, although the success rate was not high. A simple detachable external heating system with a vacuum chamber was introduced to generate temperatures greater than 1000 K. The high-pressure in-situ X-ray laminography technique [Nomura and Uesugi, 2016] was introduced to determine the strain state within a sample under high-pressure conditions. The X-ray diffraction measurement system was introduced to determine the stress state of the sample under high-pressure and high-temperature deformation conditions. A combined X-ray diffraction and X-ray imaging measurement system was set up in an identical beamline (BL47XU of SPring-8, Japan). Through this combined measurement technique with the rotational diamond anvil cell, we succeeded in extending the P-T range of the quantitative experimental studies to understand the rheological properties of the deep Earth materials. We present recent technical developments and their relevant applications.