Gyulai Iván - Szakáll Sándor szerk.: Natura Borsodiensis I. (Miskolc, 1986)

SZAKÁLL SÁNDOR-TAKÁCS JÓZSKP-WEISZBURG TAMÁS: A legyesbényei régi zsidó-temető melletti kőbánya ásványai

MINERAL OP THE STONE-PIT BEING BY THE OLD JEWISH CEMENTERY IN LEGYESBÉNYE Abstract The village of Legyesbénye is situated near Szerencs, NE-Hungary /Pig.l./. Its surroundings are built up of andesitic and rhyolitic tuffs and lava sheets of the Miocene volcanic complex of the EperjesTokaj Mts. The area belongs to what is called the Inner Carpathian Volcanic Chain. During the final stage of the volcanic activity, simultaneously with liranic sedimentation, intensive hydrothermal processes took place, as a result of which kaolinitic and montmorillonitic clays as well as limnoquartzitic sediments were formed. The unique mineral association found in the quarry of Legyesbénye /Pig.

2./ was formed also by the above mentioned hydrothermal processes. Both the syngenetic cavities and the postgenetic /tectonic/ cracks and fissures of the limnoquartzite are filled predominantly by alunite. Alunite appears in the form of euhedral crystals, the size of which reaches sometimes 5 mm /Table I.

2./. Several generations of alunite could be distinguished. As to their chemical composition, no traces of K-Na replacement could be indicated by the applied analytical techniques /microanalysis, TEM, X-ray diffraction/. The cavityfilling alunite is essentially homogeneous with only minor amounts of Pb and Zn substituting K. At places this phase appears alternating and in close association with a water containing K-free aluminium sulphate. /Table VI. 1-4»/ When filling postgenetic /tectonic/ cracks, alunite always has its K-positions partly occupied by Pb and Zn The discontinuity of the uptake of Pb and Zn during the growth of the crystals resulted in a well-defined zonality /Table II.

1-3./ At the same time alunite exhibits also a characteristic sector zoning /Table II.

4»/ - a feature not yet described in connection with this mineral /according to our present knowledge/. When filling syngenetic cavities, alunite is accompanied by a series of various other minerals. The occurrence of otavite /CdCO^/ grains of 1 to 20 micrometer size /Pig.

6., Table III. 2-3«/ is quite unique, since this mineral /free of impurities as such/ has been described so far only from its type locality in South Africa. Beside otavite also malachite, baryte and an Ag- and Zn-containing mineral /aurichalcite/ were identified in the same quarry /Table V.1-4.» VIII.

1-4., VII.

1-4./. At places the growth of alunite seems to have been oriented by apatite /Table V.l-2./ - an accessory component of 2- 3the altered volcanic host rock. In such cases an /SO./ - /P0,/ 4 4 substitution is found in the core of the alunitized apatite grains.