Rheology of two-phase systems: A microphysical and observational approach
Rheology of two-phase systems: A microphysical and observational approach
复制标题
两相系统的流变学：微观物理和观察方法
DOI：
10.1016/j.jsg.2015.05.003
复制
发表时间：
2015
影响因子：
3.1
通讯作者：
J. Platt
中科院分区：
文献类型：
--
作者：
J. Platt
韧性剪切带通常包含以紧密混合的细粒两相或多相材料为特征的高应变岩石的独特条带。这些超糜棱岩带比周围的物质弱，可能在应变局部化中起关键作用。这些区域是如何形成的，这些相是如何均匀分散的，整体流变学以及对粒度的控制都不清楚。以下一般情况可能会解决这些问题。1）位错蠕变和动态再结晶导致晶粒尺寸减小：通常，两相的再结晶晶粒尺寸不同。2）晶粒尺寸减小导致切换到晶界扩散蠕变，这需要晶界滑动。扩散允许一个相填充另一个相的晶粒之间的空隙：这在晶粒较细的相中发生得最快。因此，所得混合物的晶粒尺寸由更细晶粒相的晶粒尺寸控制。这导致了两相的混合和分散，产生了细粒的、均匀分散的两相聚集体。3）体积流变学将由两相的晶界扩散蠕变控制，晶粒尺寸由细粒相控制。基于这些概念，使用适当的混合定律，可以开发出石英-长石和橄榄石-斜方辉石超糜棱岩的体积流动定律。
Ductile shear zones commonly contain distinctive bands of high strain rock characterized by intimately mixed fine-grained two-phase or polyphase material. These ultramylonite bands are weaker than the surrounding material, and may play a critical role in strain localization. How such zones develop, how the phases become evenly dispersed, the bulk rheology, and the controls on grain size, are all unclear. The following generic scenario may resolve some of these questions.1) Dislocation creep and dynamic recrystallization cause grain-size reduction: commonly, the recrystallized grain sizes of the two phases differ.2) Grain size reduction causes a switch to grain-boundary diffusion creep, which requires grain-boundary sliding. Diffusion allows one phase to fill spaces that open between grains of the other: this will happen most rapidly in the finer-grained phase. The grain size of the resulting mixture is therefore controlled by that of the finer-grained phase. This leads to mixing and dispersion of the two phases, producing a fine-grained, evenly dispersed two-phase aggregate.3) The bulk rheology will be controlled by grain-boundary diffusion creep of the two phases, with the grain size controlled by the finer-grained phase.Bulk flow laws can be developed for quartz-feldspar and olivine-orthopyroxene ultramylonites based on these concepts, using appropriate mixing laws.
影响因子：
4.8
作者：
Hecht, M. H.;Marshall, J.;Woida, P. M.
通讯作者：
Woida, P. M.