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糜棱岩中相对坚硬矿物的碎斑通常具有由重结晶物质的尾部所决定的内部单斜对称性。碎斑及其尾部称为‘碎斑体系’。它可以作为有价值的旋涡方向指示物。根据尾部的几何特征可把碎斑体系分为σ-型和δ-型。σ-型有楔形重结晶的尾部,其中线分布在平行于尾部包含体系对称轴的参照面的两侧对边上。σ-型进一步分为σa-型,这种碎斑在相对均匀的基质中是孤零的;和σb-型,其碎斑是与基质中的剪切带叶理相伴出现。典型的σ-型有细长的重结晶的尾部,它的中线横穿邻近碎斑的参照面。接近碎斑的基质物质经常出现湾形,尾部还呈现了明显弯曲。糜棱岩中碎斑体系是与碎斑相邻其质中非共轴流动使碎斑外壳中相对弱功力重结晶颗粒集合体改变其形状而发育起来的。这一习性已在剪切箱的实验中被模拟。利用嵌入硅质油灰的刚性圆柱体周围的波动标志线进行简单剪切实验。这个实验是在不同变形速率条件下逐渐减小刚柱直径去模拟重结晶速率(R)相对变形速率(γ)的变化。R/γ比值决定发育何种碎斑体系的最重要因素之一。高R/γ值时,从碎斑流开的重结晶物质不断地被新生颗粒听补充,同时发育了楔形的σa-型尾部。低R/γ值时,相对地没有多少新生颗粒补充到变细的尾部。由于碎斑的旋转运动产生的牵引作用使尾部偏转。此外,大多数碎斑系统在低剪切应变时是σa-型或不显单斜对称,而σ-型仅在剪切应变中发育。复杂的碎斑体系以两个世代的尾部为特征。可在很多所研究的天然剪切带中见到,在模拟剪切带中由于不稳定的R/γ,也可以形成。用单个的σa-型和σ-型碎斑体系做为旋涡方向的指示物的使用条件是:体系应有一个单斜对称;基质颗粒粒度应小于碎斑的粒度;基质组构是均匀的;变形史简单以及在垂直于糜棱岩中推测的总旋涡向量的切面上进行。
The crust of relatively hard minerals in mylonites usually has an internal monoclinic symmetry determined by the tail of the recrystallized material. The plaque and its tail are called ’plaque system’. It can serve as a valuable vortex direction indicator. According to the geometric characteristics of the tail can be divided into plaque system σ-type and δ-type. σ-shaped wedged recrystallized tails with lines distributed on opposite sides of the reference plane parallel to the reference plane containing the axis of symmetry of the tail. The σ-type is further classified as σa-type, which is solitary and zero in a relatively homogeneous matrix; and σb-type, with its associated with shear banding in the matrix. A typical sigma-type slender recrystallized tail whose midline crosses the reference surface of the adjacent crush. The matrix material close to the crust often appears bay-shaped, and the tail also shows a pronounced curvature. Mottled rock in the cricket system is adjacent to the crust and its mass in the non-coaxial flow in the crust shell relatively weak power of recrystallized particle assembly to change its shape and development. This behavior has been modeled in the shear box experiment. Simple shearing experiments were performed using fluctuating mark lines around a rigid cylinder embedded with siliceous putty. The experiment is to simulate the change of R (relative deformation rate) under the different deformation rate. The R / γ ratio determines one of the most important factors in the development of which spot system. At high R / γ values, the recrystallized material flowing from the shards is constantly replenished by nascent particles, and a wedge-shaped sigma-type tail is developed. At low R / γ values, relatively few newborn particles are added to the tapered tail. The tail is deflected due to the traction created by the rotational movement of the spot. In addition, most plaque systems are sigma-type or non-monoclinic at low shear strain, whereas σ-type develops only in shear strain. The complex crust system is characterized by two generations of tails. It can be seen in many of the natural shear zones studied, and can also be formed in the simulated shear zone due to unstable R / γ. The use of a single sigma-type and sigma-type crush system as an indicator of vortex direction is such that the system should have a monoclinic symmetry; the particle size of the matrix should be smaller than the size of the crush; the matrix configuration is uniform; The deformation history is simple and is carried out on the slice perpendicular to the total vorticity vector in the mylonite.