Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 50. (Budapest 1958)

Kaszanitzky, F.: Genetic relations of the Pátka-Kőrakáshegy ore occurrence, Velence area, North Central Hungary

crystals is covered by a yellow powdery substance, being a secondary product of alteration. It is most probably valentinite or cervantite. Attempts at an exact determination have had no success. Antimonite is not the product of a separate phase of ore mineralization as it has been suggested by J. Kiss but rather the latest product of the primary ore deposition, forming an integral part of the same. On the upper level (more exactly, in the working at the bottom of the inclined shaft), there is an occurrence of a smaller amount of secondary minerals such as cerussite, covellite, hypergene chalcocite, azurite, malachite and ochre of antimony. These have been formed by descendent solutions oxidizing the primary ores. Their amount is insignificant as related to that of the primary ore. A zone of oxidation, however, has failed to develop. Only a process of disperse oxidation may be spoken of. Secondary minerals also occur on the deeper levels, although they are much more scarce there. Of the gangue minerals gypsum is found even at the bottom level (—70 metres) in the form of minute clear transparent phenocrysts elongated along the c-axis, of the size 1 to 2 millimetres. Gypsum is likewise hypergene. Of the non-metallic minerals the occurrence contains fluorite in greater quantity. By microscopic investigation it was possible to distinguish several generations. The most ancient one is independent of the sulphidic ore formation. In dike sections containing no ore minerals it occurs in the form of smaller grains or greater aggregates of 3 to 4 centimetres size, interwoven, as it were, with the gangue of the dike, syngenetically with the quartz material of the same. This fluorite generation has a more or less massive appearance and is mostly of a light green colour. The second generation of fluorite occurs in a much dispersed distribution, in small quantities in mineralized parts of the dike. Its minute idiomorphic cubes are found invariably in the younger quartz gangue filling the fissures of ore minerals. The size of individual crystals but seldom exceeds 50 microns. They are partly digested by quartz. This generation is syngenetic with ore formation, but within the same it is subsequent to the ore minerals. The third generation of fluorite forms thin-veins, crossing silicic and mineralized parts of the dike alike. These fluorite veinlets of mostly pink to violet colour also occur in the fissures of the country rock. This generation of fluorite was formed subsequently to ore mineralization. Considering the great mobility of fluorite it is assumed that the three generations of fluorite are not independent of each other but rather that the first generation of fluorite was partially resorbed and redeposited by metalliferous solutions. According to older data (A. Földvári), in common occurrences of fluorite and ore minerals on the top level the quantity of ore minerals was exceeded by that of fluorite. Because of the collapse of Mr. Földvári'

s Shaft no material was available from this locality. The ore material is rather homogeneous between the individual levels. In the development of the ore material in the different horizons we have found no essential differences. There is a complete lack of signs indicating a downward transition towards a facies of higher temperature. Because of the absence of vertical zonality the character of ore mineralization may be supposed to hold on towards lower levels.