Creep of Pyroxene Single Crystals

一套高温蠕变实验将研究单斜辉石(透辉石和钙辉石)和斜方辉石(铜辉石和顽辉石)在1大气压下严格控制的热力学条件下的流变性。总压力，以确定适合于这些矿物的晶内流动规律和变形机制，以推断到上地幔条件。特别是，将测量蠕变速率与氧分压和二氧化硅活性的关系。橄榄石通常被认为是上地幔中最丰富和最弱的矿物，因此上地幔的流变性通常是利用橄榄石单晶和多晶的高温变形实验结果来模拟的。然而，在化学不均匀的地幔中，辉石含量局部较高的地区，如俯冲带，变形将受到辉石变形的控制。

A suite of high-temperature creep experiments will investigate the rheology of single crystals of clinopyroxene (diopside and hedenbergite) and orthopyroxene (bronzite and enstatite) under carefully-controlled thermodynamic conditions at 1 atm. total pressure, to determine intracrystalline flow laws and mechanisms of deformation appropriate to these minerals for extrapolation to upper mantle conditions. In particular, the dependence of creep rate on oxygen partial pressure and on the activity of silica will be measured. Olivine is generally regarded as both the most abundant and weakest mineral in the upper mantle, so that the rheology of the upper mantle is usually modelled using the results of high-temperature deformation experiments on olivine single crystals and polycrystals. However, in a chemically heterogeneous mantle, deformation in regions with a locally high pyroxene content, such as subduction zones, will be controlled by the deformation of pyroxenes.