Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 51. (Budapest 1959)

Kaszanitzky, F.: Genetic relation of ore occurrence in the Western Mátra Mountains, North Eastern Hungary

A third tectonic phase gave rise to fissures striking 315 to 150 degrees, bearing small amounts of scattered ore. There are gradual transitions between this phase and the phase having resulted in ore formation. On the basis of some disclosures a further, fourth tectonic phase may also be distinguished. The fissures formed by this one run along the strikes of the previously formed veins, bearing small amounts of amethyst, sphalerite and chalcopyrite. The greater veins are traversed by a relatively small number of faults. The displacements generally do not exceed 10 metres. An exception is made by the fault of 305° strike and 80° south-south-westerly dip, observed in the main gallery in front of the ancient machine room, displacing the southern flank of Károly vein 16 metres towards the NW. The fault is observed through a greater distance and in several horizons. It even manifests itself in a fault scarp on the surface above Károly vein. It also displaces the Péter-Pál vein. The comparison of the structure of the displaced parts of the vein and the morphology of the fault scarp both indicate that the throw of the fault has been considerably larger than the amount of horizontal displacement mentioned above. This is the reason why the veins south of the fault are ore-poor on the level of the main gallery, showing exploitable ore quantities only on the —100 metre level. General description of the veins By their direction of strike, the veins of the area, cropping out on the surface or known from the mining, may be divided into three groups. The vein system richest in ore and disclosed most thoroughly by the mining operations carried out up to now strikes approximately north (more exactly, northnorthwest ; Károly, Aranybányabérc veins, Northern part of Péter-Pál vein, Hidegkút I and II veins, Szákacsurgó veins and the Vereskő vein swarm known from surface outcrops). The second group of veins is almost perpendicular to the above one, striking ESE-WNW. Of the veins disclosed by mining, the Malombérc, Arany Péter, Bányabérc veins, the Southern Pelyhes vein, traversed by a haulage gallery, and some veins disclosed by prospecting trenches, namely the Northern Pelyhes, Mátraszentimre, Nagytölgyesbérc, Mátrakeresztes and Katalin veins belong to this group. The third group of veins, of NNE-SSW strike, is of lesser importance. The southern part of Péter-Pál vein (formerly named Bükkszéi I) and the "2150" vein belong here. With the exception of the Sou+hern Pelyhes and Bányabérc veins, the veins disclosed by mining are located in the area of "inclusion-rich" andésite, older than the Mátra andésite. This former type of rock is characterized by containing a large number of inclusions of a subvolcanic andésite type. The geologists interested in the area have, after G. Panto, considered ore mineralization to have been connected with this kind of andésite and have thought the veins situated without the area of inclusion-rich andésite to be sterile. However, since the disclosure of the Pelyhes and Bányabérc veins it has become clear that ore mineralization is not restricted to this area. The veins of the ore area are generally of short extension. The longest one, the Károly vein, measures 900 metres. The rest do not exceed 400 metres. The workable part of the ore-bearing veins is in general 60 per cent of their total length. The thickness of veins ranges from 60 to 250 centimetres. The