Ugrás a tartalomhoz

Mineralogy Petrology

Prof. Árpád Dávid (2011)

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Kisnána, andesite quarry

Kisnána, andesite quarry

The locality can be approached on the Eger, Verpelét, Kisnána, Domoszló, Gyöngyös route by bus (Fig. 5.4.1.). The bus have to be left in the station before László Móré’s castle which is Kisnána’s notable historical building.The road which leads to the quarry is directly in the opposite of the castle.The mine’s area can be found 1 km away from kisnána to the North, about 220 m height above sea level. The quarry’s southern part lies directly to the Hátsó-Tarnóca-creek. Its North-South extension is 200 meters, and its East-West extension is:400 metres. The locality’ geographical coordinates are: 47°52’00.61”N, 20°09’13.89”E (Fig. 5.4.2.).

Fig. 5.4.1. Geographical position of the Kisnána, andesite quarry

Fig. 5.4.2. Topographical map of Kisnána and its environs

Fig. 5.4.3. Geological map of Kisnána and its environs

 

The quarry exposes Miocene, fine-grained, dark grey pyroxene-andesite. This rock formed during the main volcanic activity of the region, some 15-16 million years before. In the black, fresh andesite, which can be found at the lower part of the quarry, there are cm, furthermore dm measured bladder cavities occur. There are two mineral formation processes took place in the pyroxene-andesite of Kisnána. An exhalitive mineral formation and a hydrothermal one (Fig. 5.4.3.).

The most frequent minerals of the locality:

Aragonite: colourless, elongated columnar, acicular, crystal groups, respectively pink, soemtimes completely filling up the cavities. Their length can reach 10 cm.

Barite: colourless, 1-3 mm tabs.

Biotite: 1-2 mm fulvous, black, hexagonal lamellar crystals.

Goethite: tan crusts, coatings, botryoidal, romboeders. It often appears as pseudomorph after siderite.

Hornblende: black, mm planked, acicular crystals.

Calcite: white, yellow or greenish romboeders, spherical aggregates and encrustments.

Clinoptilolite: colourless, mm tabular crystals. It often occures with saponine.

Quartz: colourless, 1-2 mm columnar crystals, respectively more cm stout inclusions.

Mn-oxides: purplish brown lamellar sets, respectively black spheres and encrustments.

Montmorillonite: white or slightly coloured, fat touching, predominantly very fine grains.

Opal: tan stout masses.

Saponine: light green, greyish, earthy nests, clay-like masses

Siderite: light brown, greyish brown, dark brown, sometimes vigorously colour playing surfaced romboeders, spheres and encrustments.

Tridimite: yellowish, 1-2 mm tabular, fan-like or star shaped groups.

Detail of the andesite quarry at Kisnána

The mineral-rich part of the quarry at Kisnána

Fragmented, bedded andesite at the quarry of Kisnána

Thin bedded, dark coloured andesite at the Kisnána quarry

Porphyritic textured, dark coloured andesite at Kisnána

Cavities in andesite contain minerals in great variety

Barite crystals in an andesite cavity

Large quartz crystals in an andesite cavity

Brown coloured opal from Kisnána

Botryoidal chalcedony from Kisnána

Small barite crystals in the cavity of the andesite

Vitreous aragonite crystals in andesite

Fibrous aragonite in andesite

Spheroidal calcite in andesite

Siderite crystals in the cavity of the andesite

Spherosiderite in the cavity of the andesite

Manganese-oxide encrustation on the surface calcite crystals

Selected literatures

Bognár L. 1987: Ásványhatározó. – Gondolat Kiadó, Budapest, p. 478.

Gasztonyi É. 2010: A Mátra hegység ércesedése. – In: Baráz Cs. (szerk.) 2010: A mátrai Tájvédelmi Körzet. Heves és Nógrád határán. – Eger, 53-63.

Kern Z. 2007: Nemesopál, opál, faopál: a kisnánai lelet. – A Földgömb: a Magyar Földrajzi Társaság folyóirata, 9(1). 12-13.

Szakáll S. (szerk.) 1996: 100 magyarországi ásványlelőhely. – Minerofil Kiskönyvtár II., p. 139.

Szakáll S. 2008: Barangolás az ásványok világában. – Debrecen, p. 120.

Szakáll S. 2010: A Mátra ásványtani jellemzése. – In: Baráz Cs. (szerk.) 2010: A mátrai Tájvédelmi Körzet. Heves és Nógrád határán. – Eger, 65-77.

Szakáll S. – Jánosi M. 1995: Magyarország ásványai. Kiállításvezető. – Miskolc, 44-56.