Electron backscatter diffraction analysis to determine the mechanisms that operated during dynamic recrystallisation of quartz-rich rocks
Electron backscatter diffraction analysis to determine the mechanisms that operated during dynamic recrystallisation of quartz-rich rocks
复制标题
电子背散射衍射分析以确定富含石英岩石动态重结晶过程中的运行机制
DOI：
10.1016/j.jsg.2012.01.001
复制
发表时间：
2012
影响因子：
3.1
通讯作者：
J. Wheeler
中科院分区：
文献类型：
--
作者：
A. Halfpenny;D. Prior;J. Wheeler
从样品微观结构中确定控制成核和再结晶的机制是了解微观结构如何随时间形成和演变的关键。我们的研究目的是应用定量分析方法来确定控制成核、再结晶和微观结构改性的机制。利用电子背散射衍射技术，对不同温度和压力条件下自然变形的富石英岩石的微观结构进行了定量分析。我们的研究结果表明，再结晶晶粒尺寸与亚晶粒尺寸的比值小于1（这里的数据中为0.5-0.7）表明凸起形核，而比值为1表明亚晶粒旋转形核。其他支持亚粒旋转成核的证据是，从原始原岩“母粒”的中心到边缘的取向偏差增加。所有样品都显示出晶界滑动导致微观结构改变的证据，包括晶粒之间的取向角增加和再结晶晶粒在母晶之间的运动。通过系统地分析样品的微观结构，可以分离出证据来确定控制成核和再结晶的机制，以及能够识别微观结构的改性机制。通过EBSD使用微观结构定量，可以从客观的角度系统地分析来自任何位置的样品。
Determination of the controlling nucleation and recrystallisation mechanisms from a samples microstructure are essential for understanding how the microstructure formed and evolved through time. The aim of our research was to apply a quantified analytical approach to the identification of the controlling nucleation, recrystallisation and microstructural modification mechanisms. We used electron backscatter diffraction to quantify the microstructures of naturally deformed quartz-rich rocks which were deformed at various temperature and pressure conditions. Our results show that ratios of the recrystallised grain size to the subgrain size with values less than 1 (0.5–0.7 in the data presented here) suggest bulge nucleation, whereas ratios of ∼1 suggest subgrain rotation nucleation. Other supporting evidence for subgrain rotation nucleation is an increase in misorientation from the centre of an original protolith ‘parent’ grain to the edge. All samples show evidence for modification of the microstructure due to grain boundary sliding including increased misorientation angles between grains and movement of recrystallised grains between parent grains. By systematically analysing sample microstructures it is possible to separate out evidence to determine the controlling nucleation and recrystallisation mechanisms, as well as being able to identify microstructure modification mechanisms. Using microstructural quantification via EBSD allows a systematic methodology to analyse samples from any location from an objective viewpoint.