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深熔作用(Anatexis)引起了地壳内部固体物质的重溶与熔融和进一步的初始花岗质岩浆的形成。本文主要从岩相学角度对河北平山阜平岩群3种主要变质岩类中一部分岩石在薄片中所显示的初期深熔特征进行了报道,提出识别深熔作用发生发展初期的一些岩相学标志,为相应的理论探讨提供岩相学方面的依据。区域变质岩石初始深熔的共同特征之一是不同矿物粒度都较相应的同类变质岩石为粗。由于经历粒间流体作用的重溶、溶蚀乃至再度晶出的过程,长英质岩石中长石、石英等矿物改变为具有弯曲、波纹状外形的缝合线结构,而“铰链状结构”的形成则是两微斜长石颗粒之间出现钠交代的结果。深熔作用过程中微斜长石显示出不均匀的光性特征,形成具交代成因的条纹长石细脉和条痕;斜长石出现不规则长方形和补丁状的微斜长石反条纹长石,显示“糟化”或绢云母化,或存在不同程度的“暗化”区域,也可转变成为纤维状至细柱状夕线石,沿斜长石中的一些细小裂纹和遭受应变的解理还出现几乎不透明的物质,它们可能原由深熔作用所形成,可称之为“网格状结构”;黑云母可部分地发生分解,在适当的温压条件下则完全分解,形成原可能为熔体的物质,也可转变成为纤维状至细柱状夕线石;角闪石存在一定程度的“暗化”,并形成与斜长石中所见类似的“网
Anatexis caused the re-dissolution and melting of solid matter inside the crust and the formation of further initial granitic magmas. In this paper, some of the three main metamorphic rocks of the Fuping Group in Pingshan, Hebei Province are reported from the perspective of lithofacies. The characteristics of some early lithofacies in the thin sections are presented. Some petrographic marks , To provide the basis for the corresponding theoretical discussion on petrography. One of the common features of the initial deep-melt of the metamorphic rocks is that the coarse-grained rocks with different mineralogical sizes are more similar than the corresponding metamorphic rocks. Due to the process of re-dissolution, dissolution and even recrystallization of intergranular fluid, the minerals such as feldspar and quartz in the feldspathic rocks are changed into suture structures with curved and wavy shapes, whereas the formation of “hinge-like structures” It is the result of sodium metasomatism between two slightly plagioclase particles. Micro-plagioclase shows non-uniform phototropism during the process of deep melting, forming striated feldspathic veins and streaks with the genesis of metasoma; plagioclase appears irregular plagioclase and patch-like anti-stripe length Stones, which show “spoilage” or sericitization, or the presence of varying degrees of “darkening” of the area, can also be transformed into fine-grained sillimanite, some small cracks along the plagioclase, and solutions to strain It also appears almost opaque material, they may have been formed by the role of the deep melt, which can be called “grid-like structure”; biotite can be partially decomposed under the appropriate conditions of temperature and pressure are completely decomposed to form the original may As a melt material, can also be transformed into a fibrillar to fine columnar sillimanite; there is some degree of “darkening” of amphibole and forms a “net” similar to that seen in plagioclase