Kalcium-foszfátok eloszlása a Baradla-Domica-barlangrendszerben
Mineralogical investigation of calcium-phosphates from the Baradla-Domica Cave, Aggtelek Karst, Hungary
Keywords:Baradla-barlang, foszfátok, taranakit, brushit, röntgen-pordiffrakció
We elaborated the Baradla-Domica Cave system from mineralogical aspect. Samples were collected from the Hall of Indian Pagodas, Hall of Palm Woods, Bat Branch, Fox Branch, Mórea and Libanon Hills and Münnich Passage from walls, dripstones, bones, teeth, and three positions (upper, middle and lower section) within the guano deposits. 174 samples were analyzed by SEM/EDS in order to obtain their chemical compounds and select the phosphate-bearing samples to further investigate them by methods of X-ray diffraction (XRD), thermal analysis (DTA) and infrared spectroscopy (IR). 25 samples were studied by XRD, 1 sample was analysed by DTA and 2 other samples were examined by IR. The phosphate assemblage is composed of hydroxylapatite, taranakite, brushite, ardealite(?) accompanied by calcite, quartz and gypsum and some organic matter. Most phosphate minerals form complex intergrowths, separating them is very difficult. Intercresence of phosphate minerals in caves is very typical. Their morphology could not be described by stereomicroscopy, as the crystallites were under 50 µm.