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
Genetic Relations of the Pátka—Kőrakáshegy Ore Occurrence, Velence Area, North Central Hungary By F. Kaszanitzky, Budapest The ore occurrence mentioned in the title lies on the northwesterly margin of the Palaeozoic granite pluton of asymmetric structure, forming the so-called Velence Mountains in the axis of the Transdanubian part of the Central Hungarian Mountains. The Korakáshegy (Stone Heap Hill) is separated from the main mass of the mountains by a fault of northeasterly strike. It was along this same fault that the Palaeozoic formations west of our occurrence have sunk below. The intrusion of the granite magma having formed the Velence Mountains pluton was due (according to E. Vadász, L. L ó c z y sen., A. Földvári) to the Sudetic-Asturian or ogenetic phases. Intrusion was later followed by a broad arching of the area as well as by intense post-plutonic activity, having yielded several hundred dikes of granite porphyry, aplite, kersantite and quartz (in this order of succession). The strike of these dike formations is similar to that of the entire mountain (northeast-southwest). The biotite granite of hypidiomorphic granular texture, consisting of average-sized grains, is a rather uniform formation. It is but at the marginal parts of the pluton that a variety of Porphyrie texture is found to occur. As to chemical composition, the rock belongs to the group of acid calc-alkali granites. The granite porphyry is somewhat more alkaline than the granite itself (A. V e n d 1). On the other hand, the aplites are characterized by greater potassium content. Pegmatitic formations of the area treated are of subordinate importance. The formation of the quartz veins, representing the final phase of magmatic activity, took place within an interval reaching well into the Saalic phase of orogeny. The average width of the quartz veins is not exceeding 1 to 2 metres. However, they may be traced continuously to distances of 100 to 2500 metres along strike. The strike of the latest set of quartz veins is perpendicular to that of the mountain. The quartz filling of the ore occurence Pátka—Kőrakáshegy is, from the genetic point of view, the result of this last phase of dike formation. We have no definite knowledge as to the occurrence of Permian to upper Eocene deposits in our territory. Of these, only the former presence of Permian formations is proven. In the course of the late Eocene, an effusion of andésites has taken place in the Eastern part of the mountain. The possibility of genetic linkage between the andésite effusion and the Pátka ore formation certainly exists : however, to examine this possibility, further exploratory work will be necessary. Geologic structure of the occurrence. Constituting the geology of the immediate vicinity of the ore occurrence are somewhat metamorphosed slates of sedimentary origin, granite porphyry, aplite, vein quartz, accompanied by young sediments of Pannonian (upper Miocene — lower Pliocene) and Pleistocene age. The most ancient rock of the environment is the knotty slate occurring at the granite contact. Slate and granite are invariablv in tectonic contact, along structural lines of north-northwesterly strike.
