藍晶石・珪線石・紅柱石の安定關係と變成岩の生成條件
藍晶石・珪線石・紅柱石の安定關係と變成岩の生成條件
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蓝晶石、硅线石、红柱石的稳定性关系与变质岩的形成条件
DOI：
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发表时间：
1950
期刊：
影响因子：
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通讯作者：
秋穗 都城
中科院分区：
文献类型：
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作者：
秋穗 都城
本文对蓝晶石、硅线石、红柱石和莫来石的稳定性关系进行了推断。稳定性关系如图所示，图中也大致显示了各种矿物相对应的条件范围。这张图表主要是根据下列事实构成的。在榴辉岩等高压岩石中，蓝晶石较为常见，硅线石较为少见。在图1中h、d或其附近的一般高压区域变质作用中，蓝晶石在较低温度下形成，硅线石在较高温度下形成。在某些区域变质作用的情况下，如图中所示，普遍的压力相对较低，也会出现红柱石。在热变质作用中，即使在低压s， r或图1中仍然很低的压力下，红柱石最常见，但在一些高度变质的岩石中也会出现硅线石。在极低的压力下，莫来石至少在高温下形成。就作者所知，说明这些事实的图表无一例外地与硅酸铝矿物的所有这些和其他发生模式相一致。从图中可以看出，这些矿物可以作为它们形成压力的指示物。如果将来能定量地确定其稳定性关系，就有可能对变质过程中的压力进行估计。红柱石常见于角石中，蓝晶石常见于结晶组团中。的解释没有蓝晶石的普通接触变质带可能是晕太强烈的内部区域加热蓝晶石是稳定的,这种矿物稳定只在低温下(见图)温和的压力,和外区再结晶不完整,从蓝晶石,或者其他低温矿物,e, g。,绢云母,粘土矿物等,形成的,而不是蓝晶石。然而，在非常特殊的情况下，蓝晶石是热变质作用的产物。在大多数情况下，当锆石-红柱石或蓝晶石-红柱石组合出现时，每对矿物中的一种都表现出比另一种更早形成的特征，然后这种组合可以被认为是一种非平衡组合。然而，在某些情况下，这种联系似乎代表着一种稳定的联系。蓝晶石和红柱石的稳定结合并不违反矿物学相规律，因为它们通常不是纯的Al2SiO5组成的化合物，而是含有一定量的其他化合物作为固溶体。
In this paper is given an inference as to the stability relation of kyanite, sillimanite, andalusite, and mullite., The Stability relation is represented in the figure, in which the ranges of conditions corresponding to varius mineral facies are also roughly shown., This diagram was constructed chiefly on the basis of the following facts., In such high-pressre rocks as eclogite, kyanite is commonly found but sillimanite is rare., In ordinary regional metamorphism under comparatively high pressures as shown by h, d or thereabouts in Fig., 1, kyanite is formed at lower temperatures, and sillimanite at higher., In some cases of regional metamorphism where the pressures prevailing are relatively low as shown by s or therebouts in the diagram, andalusite also occurs., In thermal metamorphism under even low pressures s, r or still low in Fig., 1, andalusite is most commonly found, but in some highly metamorphased rocks sillimanite also occures., Under very low pressures mullite is formed, at least at high temperatures., The figure illustrating these facts is consistent with all these and other modes of occurrence of the aluminium-silicate minerals without exception, insofar as the writer is aware., It may be seen from the figure that these minerals are useful as indicators of pressures of their formation., If we can determine quantitativery the stability relation in the future, the estimation of pressure in metamorphic processes may become possible., It is quite usual that andalusite occurs in hornfelses, and kyanite in crystalline shists., The explanation of the absence of kyanite in the ordinary contact metamorphic aureole may be that the inner zone of the aureole was too intensely heated for kyanite to be stable, this mineral being stable only at low temperatures (as is seen in the figure) under moderate pressures, and in the outer zone recrystallization was not so complete as to from kyanite, or other low-temperature minerals, e., g., sericite, clay-minerals, etc., were formed instead of kyanite., In very exceptional cases, however, kyanite occurs as a product of thermal metamorphism., In most cases where the association staurolite-andulusite or kyanite-andalusite occurs, one mineral of each of these pairs shows such features as to indicate earlier formation than the other, and then the association may be regarded as one of non-equilibrium., There seems to be some cases, however, where the association represents a stable one., The stable association of kyanite with andalusite does not conflict with the mineralogical phase rule, for they are not usually the pure compounds of the compositions Al2SiO5, but contain some quantities of other compounds as solid solutions.,