The Kasuga mine is located about 6 km east of Makurazaki City, Kagoshima Prefecture, Japan.
The gold ore of the Kasuga mine occurs in a net work of veins which are fissure fillings in. hydrothermally silicified propylitic tuff, tuff-breccia, and propylite of Tertiary age. The hydrothermal solutions that caused the silicification produced many other alteration effects in wall rocks resulting in an interesting zonal arrangement of the mineral assemblages.
It was discovered by the writer that vertical and horizontal zoning of mineral assemblages exist in such a scheme as follows;
1) Vertical zoning in the central part from upper to lower: silicified zone→alunite zone.
2) Horizontal zoning from inner to outer: silicified zone→dickite zone→limonite·kaolinite zone→kaolinite zone→aoriginal rock.
Determination of the constituent minerals of each altered zone was done optically and by differential thermal analyses in combination with X-ray analyses. The variation of chemical components in each altered zone was investigated by chemical analyses.
Among the component of the original rock, SiO₂ and Ti seem to have remained in place, but some SiO₂ has been added. Small amounts of Al and a large proportion of the other chemical components have been removed. Some of the chemical components have been concentrated in the several zones of the aureole of the hydrothermal alteration.

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The writers determined electronically the formation temperatures of several mineral deposits in Japan using F. G. Smith′s decrepitation method.
The Akenobe deposit is classified as xenothermal which, according to Buddington, is characterized by an abnormally steep geothermal gradient. Experiments on about 70 samples, which were collected through 500ft. of vertical range show that the deposition temperature increases with increase in depth. The higher temperature mineralizations at the 500ft. level, the upper level from which the authors collected samples, average about 300°C; those at the 1000ft. level, lowest level from which samples were collected, average about 335°C. It, therefore, appears that the deposition was related to a steep geothermal gradient. The formation temperatures of this deposit range from 350°to 160°C.
The ore deposit of the Chichibu mine is a pyrometasomatic type of magnetite, zincblende and other ore minerals accompanied by skarn minerals. The formation temperatures of the minerals from this deposit are 400°to 220°C. These figures coincide with those of the Kamioka mine which is in a typical pyrometa-somatic deposit of zinc and lead.
Samples from the Hosokura mine, an epithermal deposit of zinc and lead, were also studied. Their formation temperatures are somewhat lower than those of the above two deposits. However, the decrepitation of quartz from an epithermal deposit is generally weak, so it is sometimes difficult to determine the deposition temperature from the decrepigraph obtained from the authors′ equipment.

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The Komaki mine is one of several mines which is located in the Tertiary mineralized zone of the inner part of north-eastern Japan. It is located immediately to the north of the Osarizawa mine in the north-eastern corner of Akita Prefecture. In this district, a thick formation of Miocene green tuff is widely distributed as the basement complex of the area. It is covered or intruded by various kinds of volcanic rocks such as dacite, augite andesite, lithoiditic plagioclase liparite, basalt, nevaditic plagioclase liparite, two-pyroxene andesite, etc. (listed in order of eruption). The deposition of the ore took place after the intrusion of the basalt and along the anticlinal core of the green tuff formation.
The ore deposits of the Komaki mine is epithermal and is composed of typical chlorite-copper-quartz veins(Shirane deposit) and of so-called "black ore" (Kuroko, Tateishi deposit). Surrounding these deposits are extensive masses of hydrothermally altered dacite and green tuff. The Shirane deposit is among mushroom-shaped intrusive dacite bodies. Its vein system consists of parallel veins having an NNW trend and southward inclination and having radial branches at both marginal ends. The ore minerals are pyrite, chalcopyrite, bismuthinite, sphalerite, galena, native gold and silver mineral; and gangue minerals are quartz, barite, and chlorite.
The most characteristic feature of the deposit is the wide spread supergene enrichment of the ores. Supergene chalcocite, bornite, and zinc sulphides are present down to the deepest horizon of the deposit.
The successsion of the mineralization is as follows;
(1) Formation of pyrite associated with remarkable chloritization of country rocks;
(2) Deposition of sulphide minerals and of barite. During the sulphide mineralization, the bismuthinite-massive chalcopyrite association was followed by the granular chalcopyrite-sphalerite-galena-native gold-silver minerals association.
Based on their zonal distribution and the paragenesis of ore minerals, it can be interpreted that the eastern half of the vein was mineralized at higher temperatures than the western half.

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Durch petrographische Untersuchung der Dünnschliffe der Sandsteine des Takashima Kohlenfeldes, Nagasaki Präfektur, ergibt sich Folgendes.
1) Die Beschaffenheit der Sandsteine ist erkennbar nicht nur durch deren Hauptbestandteilen, sondern auch an den Quantität und Qualität der darin enthaltenen akzessorischen Mineralien. Wenn der Erscheinungs, grad der in der Dünnschliffen aufgetrefenen einzigen akzessorischen Mineralien jeder Formation graphisch ausgedruckt wird (i.e., Verteilungskurve), so wird es klar, dass der Zustand und gleichzeitiges Auftreten. einiger Mineralien für die Sandsteine einer Formation auffallend charakteristisch sind.
An dieser graphischen Darstellung kann man gewissermassen die Sandsteine jeder Formation miteinander vergleichen, aber das gilt nur bei einer Sandsteingruppe, die zu irgend einer Formation gehört, und mit nur einem Probestück, kann man in diesem Falle, nur soeben seine Lage bestimmen. Überdies ist es nötig noch viele andere Probestücke aus darüber und darunter liegenden Schichten zu untersuchen.
2) Die Sandsteine bestehen hauptsächlich aus Quarz, Feldspath, Kieselschiefer, und vulkanischeri Bruchstü-cken und haben als akzessorischen Glaukonit, Kaliglimmer Apatit, Zirkon, Granat, Titanit, Allanit, Epidot, Turmalin, Biotit, Pyroxen, Hornblende und Opaksubstanz (meistens Eisenerze?). Die Menge von Allanit, Hornblende, Pyroxen, Biotit und Anatas sind im Vergleich mit den anderen Mineralien sehr geing.
Die Eigentümlichkeiten der Sandsteine jeder Formation sind Fdlgende: (vom Liegenden zum Hängenden gesehen)
a) Kôyaki Formation
Mittelteil……Quarzitartiger Sandstein-Arkose. Die Hauptbestandteile sind eckig oder kantig, und arm. an Kieselschiefer und vulkanischen Splittern. Keine gute Sortierung, reich an Matrix. Die meisten Probestücke enthalten Zirkon und Biotit (Frequenz=100 %), ausserdem Glimmer, Granat, Apatit, Titanit und Turmalin (Frequenz=40-50%). Die 2-3 dunnen glasisen Tuffen sind charakteristisch für den Mittelteil.
Oberteil………Die Verteilungskurve zeigt einen hohen Grad bei Kaliglimmer und Epidot: (gleich wie im Mittelteil), einen etwas geringeren Grad bei Granat, Titanit und Turmalin. Zirkon, Biotit und Apatit treten hier weniger auf als in Mittelteil. Pyroxen nur wenig und Glaukonit ist nicht vorhanden. Die roten, violetten Schiefer (Murasaki Shôdo), die im Oberteil charakteristisch sind, gehören zur Subgrauwacke.
b) Futagojima Formation
Arkosartig oder quarzitartig, enthält wenig Kieselschiefer, vulkanische Bruchstücke. Gute Sortierung und arm an Matrix. Arten und Mengen der akzessorischen Mineralien sind auffallend gering. Die Verteilungskurve zeigt einen ziemlich hohen Erscheinungsgrad bei Zirkon und Kaliglimmer, aber bei der anderen einen erstaunlich niederen Grad.

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