均匀离散分布的平面应变过程和Fry法应变测量

本文运用 Apple Macitonsh 计算机对无应变的均匀离散点分布进行系列平面应变模拟,应变叠加模式分别采用具普遍意义的成岩压实+顺层缩短(LPS)+压溶作用和成岩压实+简单剪切+压溶作用。对各应变阶段的变形点分布进行相应的 Fry 法应变测量,并配合低变形砂岩样品的 Fry 法应变分析实例.证实 Fry 法应变测量方法为一非常有用的应变测量方法,其结果不仅能较好地揭示全岩总应变特征,而且能揭示出许多应变叠加的信息,Fry 法揭示的全岩有限应变椭球主面的方位也较为真实可靠。而 Fry 法运用于应变分布不均匀的劈理化岩石中时,能揭示不同变形域的应变特征,从而达到应变分解的目的。

PLANE STRAIN PROCESSES OF ISOTROPIC ANTICLUSTERING DISTRIBUTION AND FRY'S METHOD STRAIN DETERMINATION

Using Apple Macintosh Computer,the authors modelled the progressive plane strain processes of the unstrained isotropic anticlustering point distribution.The chosen strain superimposition processes include pre-tectonic compaction+layer-parallel shorting(LPS)+ pressure-solution and pre-tectonic compaction+simple shear+pressure so- lution,which commonly exist in the deformed rocks.Applying Fry's method to the strained point pattern of each deformation phase and comparing the results with the lowly deformed sandstone samples collected in the Baliarat-Bandigo structural Zone,Southeast Australia,the authors conclude that Fry's method is a useful tool,in finite strain ellipse determi- nation.Not only can it reveal the strain characteristics of whole rock but also it can eliminate the misleading effects of pre-tectonic fabrics.Moreover,the main plane orientation of finite strain ellipsoid obtained by the method is reliable.Ap- plied to cleaved deformed rocks in which the strain ditribution is not isotropic,the method can reveal the strain natures of different deformation domains and partition the strain.