Szakáll Sándor - Weiszburg Tamás szerk.: A telkibányai érces terület ásványai (Topographia Mineralogica Hungariae 2. Miskolc, 1994)

A telkibányai ércesedés vulkanotektonikus jellemzői (Zelenka Tibor)

Topographia Mineralogica Hungáriáé Vol. II. 81-86 Miskolc, 1994 A TELKIBÁNYAI ÉRCESEDÉS VULKANOTEKTONIKUS JELLEMZŐI Volcano-tectonical characteristics of the mineralized region at Telkibánya, Tokaj-Mts., NE-Hungary Zelenka Tibor Abstract By the time of the closure of the Parathetys, the subduction of the oceanic plate was going on in the Eastern Carpathians. In the inner zones of the Carpathians, along the border of the microcontinental plates, molasse basins formed accompanied by a calc-alkaline volcanism of island-arc type. The PreSov-Tokaj volcanic range formed in a 1500-3000 m deep tectonic graben of about 100 km length (in strike) and 15-20 km width. The graben is bordered by faults in a running NNE - SSW and a NNW - SSE direction (Pantó, 1968; Gyarmati, 1977). The basement and margin of the graben are made up of Precambrian gneiss and micaschist, Paleozoic schist, sandstone and porphyritic rocks and Mezozoic carbonate rocks. These formations are folded and overthrust. On the eastern border of the graben, at Vilyvitány, these rocks erop out, while along the margins of the graben they have been encountered by boreholes at a depth of 960 m (Füzérkajata borehole No-2 Ilkey-Perlaki & Pentelényi, 1978). In the middle of the graben, to a depth 1240 m (Telkibánya borehole No-2) and at the western side of the graben (Hidasnémeti borehole No-1) to a depth 1500 m no basement rocks were encountered by the drillings. The Telkibánya area is part of the Miocene Volcanic Zone of the Tokaj Mts, where deep structural zones intersect, running about from NNW to SSE and from E to W in directions. The sinking of the graben has probably been continuous since the Middle Miocene (Fig. 1). The continuous sinking is proven by the shallow marine clayey, sandy tuffitic layers interbedded in the thick pyroclastic suite (Ilkey-Perlaki, 1978). The Middle Miocene formations are known only from boreholes (Hidasnémeti-1, Telkibánya-2, Nyíri-1, Füzérkajata-2). The graben volcanism which produced rhyolite pyroclasts of great thickness was followed by submarine dacitic-andesitic eruptions accompanied at places, by peperitic rocks (Fig. 2). The forming of an early caldera-like structure in the Middle Miocene is assumed (Fig. 3). No pyroclastics can be found in this area (Telkibánya-2), but subvolcanic andésites of great thickness with differenciated products of microdioritic composition have been formed (Széky-Fux, 1970). The andesitic rock bodies are covered by marine clay layers containing Badenien fossils, which are in contact with the potassium metasomatic volcanites (Széky- Fux). Along the border of the andésite bodies contact magmatic breccia is found (Fig. 4). In the potassium metasomatized