DI13B-4273:
Viscosity Measurements of Eclogite Melt up to 5.6 GPa and 2000 K
Monday, 15 December 2014
Hong Liu1,2, Yingwei Fei1, Lei Han1,3, Yoshio Kono4, Mingqiang Hou1, Zhisheng Zhao1 and Jianguo Du2, (1)Carnegie Inst of Washington, Washington, DC, United States, (2)CEA Key Laboratory of Earthquake Prediction (Institute of Earthquake Science), China Earthquake Administration, Beijing, China, (3)Peking University, Beijing, China, (4)Carnegie Instituion of Washing, Argonne, IL, United States
Abstract:
The melting and rheology of eclogite is critical for understanding the dynamics of the subduction zone and plate tectonic. Viscosity of eclogite melt as a function of depth is a key parameter to model the long-term chemical evolution of the subduction zone and volcanic magma. It also plays an important role in earthquakes and continent formation. However, the viscosity and rheology of eclogite melt remain poorly understood at high pressure and temperature. In this study, we have carried out in-situ falling-sphere viscometry measurements to determine the viscosity of eclogite melt from 1.3 to 5.6 GPa at temperatures between 1500 and 2000 K, using the Paris-Edinburgh cell at the 16-BM-B beamline of the High Pressure Collaborative Access Team (HPCAT) at the Advanced Photon Source. We used a natural eclogite sample with 47.7wt% SiO2. The viscosity (η) was calculated with the Stokes’ equation. The viscosity of eclogite melt decreases between 1.3 and 5.6 GPa at 2000K. At 1.4 GPa and 2000K the viscosity is 0.43 Pa·s, whereas at 5.6 GPa and 2000 K it is 0.13Pa·s. No minimum in the viscosity of eclogite was found in the measured pressure range up to 5.6 GPa.
