脈について
スポンサーリンク
概要
- 論文の詳細を見る
There are many veins in rocks, especially in the metamorphics including secondary altered rocks due to chloritisation and sericitisation., Quartz-vein, calcite-vein, aplitic vein, pegmatitic vein, epidote-vein, biotite-vein, sericite-vein and the so-called "ore-vein" are common., This paper deals with the general modes of occurrence of the various veins, from which the theory of the origin and genesis of them are concluded as follows : Up to this time, veins are generally treated as the foreign materials intruded into the country rocks from the outside sources, for example from the igneous rocks exposed near and around the country rocks, in the form of "solutions" like "silica or siliceous solution" in the case of quartzvein., It seems, however, to be difficult to explain the modes of occurrence of the veins by this theory., It is not neccessary, at least, to follow the theory with regards to the origin and genesis of the veins., Based on the facts described in this paper, there seems to be no doubt that almost all of them are seggregation veins., Quartz, calcite and the other minerals gather from the country rocks themselves through metamorphic differentiation under the physico-chemical condition represented by certain "emanation" and appear as seggregation veins., The writer will discuss briefly the problem, taking "ore-veins" as an example., In the "ore-veins" such as quartz-copper-vein and calcite-copper-vein, the quartz and calcite are called as "gang minerals," which are introduced into the country rocks from certain outside sources and carry the useful metalic ores or rather metallic elements., But it is not neccessary to consider the quartz and calcite as the foreign materials introduced into the country rocks in the form of "ore solutions.," According to the writer's opinion, they are squeezed out from the country rocks themselves, which are always altered to the chloritised and sericitised rocks in certain degree., Silica and lime are isolated from the rocks through the process of chloritisation and sericitisation, both of which are probably caused by the emanation of water, sulphur, carbon dioxide (or rather carbon monoxide), etc., called as "mineralised gas.," This free silica and lime appear as seggregation veins of quartz and calcite with or without the usefull metalic ores., It is, of course, very difficult to make clear the reason and mechanism of the seggregation of these minerals or rather elements., But on the other hand, there are many geological facts suggesting that the common rock-forming elements are roughly divided into two groups ; the one having a remarkable geochemical character with a strong tendency to make gathering as the pure mass and the other having geochemical character to disperse widely in the rocks., In this paper, the former group is geochemically called as "seggregation elements" and the latter as "dispersion elements"., Silica, lime, iron, carbon and probably alumina are the good examples of the "seggregation elements" and they strongly tend to seggregate under almost all of the geochemical conditions, even in the geochemical and geophysical environment of the surface of earth of present day., It seems to be very important that the elements which often appear as veins are almost always consisted of the "seggregation elements.,"
- 日本地質学会の論文
- 1950-10-05