Potassic

Potassium" Dynamites (Dynamite a La Potasse). A series of expls proposed in 1873 by the British Dynamite Co, Ltd (which later became the Nobel Explosives Co, Ltd), which consisted of NG 15, saltpeter 70—75, plus paraffin and powdered charcoal 7-17%. Another mixt contained NG 18, saltpeter 71, charcoal 10, and paraffin 1%... 

Among the epithermal vein-type deposits in Japan, four major types of hydrothermal alteration ean be diseriminated. They are (1) propylitie alteration, (2) potassic alteration, (3) intermediate argillic alteration, and (4) advaneed argillic alteration. The definitions of these types of alteration are mainly based on Meyer and Hemley (1967) and Rose and Burt (1979) who elassified the hydrothermal alteration in terms of alteration mineral assemblages. 

The area of the potassic alteration is not wide, compared with the propylitically altered area. The width of potassic alteration zone away from the vein is generally within several tens of meters (ca. 50 m) (Shikazono and Aoki, 1981 Imai, 1986). The potassic alteration is usually found in the intermediate vicinity of the vein in the epithermal deposits in Japan. Thus it is evident that this type of alteration occurs genetically related to the ore deposition. 

In contrast to the hardly investigated lateral zonation around Japanese epithermal vein-type deposits, a few examples of vertical zonation are known. Potassic alteration grades upwards into intermediate argillic alteration in the wall rocks for the Toyoha (Okabe and Bamba, 1976), Ohe (Tsukada and Uno, 1980), Chitose (Hasegawa et al., 1981) and Kushikino (Imai, 1986). 

Advanced arigillic alteration is found at the upper horizon than the sites of potassic and intermediate argillic alterations where the Au-Ag mineralization occurs (e.g., Seigoshi, Yatani, Kushikino, Hishikari). This type of alteration takes blanket-form in upper part and vein-form in lower part (Iwao, 1962 Shikazono, 1985a). The conspicuous zonation from upper to lower horizon is known at the Ugusu silica deposit, namely, silica zone, alunite zone, kaolinite zone and montmorillonite zone (Iwao, 1949, 1958, 1962). 

It is rather difficult to determine the sequence of each type of alteration in a mine area. However, it is widely accepted that the hydrothermal alteration proceeds as follows propylitic alteration —> potassic alteration and intermediate argillic alteration advanced argillic alteration. The actual sequence alteration might be more complicated and superimposition of each type of alteration could be common. 

Usually propylitic alteration precedes the base metal and Au-Ag mineralizations. Potassic and intermediate argillic alterations are nearly contemporaneous with ore deposition. 

Formation of albite which is characteristic mineral of propylitic alteration occurs by heating of rocks and descending fluids at recharge zone in the hydrothermal system (Giggenbach, 1984 Takeno, 1989). Thus, it is considered that the propylitic alteration takes place at recharge zone in the hydrothermal system, while potassic alteration at discharge zone. 

The dependence of concentration of K+, Na+, Ca + and H4Si04 in equilibrium with common alteration minerals (K-feldspar, Na-feldspar, quartz) on temperature is shown in Fig. 1.140 (Shikazono, 1988b). This figure demonstrates that (1) chemical compositions of hydrothermal solution depend on alteration minerals, temperature and chloride concentration, and K" " and HaSiOa concentrations increase and Ca + concentration decrease with increasing of temperature. In this case, it is considered that potassic alteration adjacent to the gold-quartz veins occurs when hydrothermal solution initially in... 

Therefore, it is thought that the mixing of acidic solution with hydrothermal solution occurred and andesite near the gold-quartz veins suffered superimposed potassic and advanced argillic alterations. 

Wendlandt RF, Eggler DH (1980) The origins of potassic magmas 2. Stability of phlogopite in natural spinel Iherzolite and in the system KalSi04-Mg0-H20-C02 at high pressures and high temperatures. Am J Sci 280 421-458... 

A -black blasting powder poudre noire au nitrate de potasse... 

Cortini, M. Hermes, O. D. (1981). Sr isotopic evidence for a multi-source origin of the potassic magmas in the Neapolitan area (S. Italy). Contrib. Mineral. Petrol., 77, 47-55. 

Harris, P. G. (1957). Zone-refining and the origin of potassic basalts. Geochim. Cosmochim. Acta, 12, 195-208. 

The influence of cosurfactant structure is best illustrated by using various isomeric alcohols with the same chain length. This is shown in Figure 4 for the system water, benzene, potassium oleate and amylic alcohols (25). The mass ratio of potassion oleate to COH is 3 5 and the temperature was 22°C. 

The extrinsic stability relations of the sodic term paragonite [NaAl2(Si3Al) Ojo(OH)2] have been investigated as have those of the potassic end-member muscovite ... 

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