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An Environmental Impact of Pyritic Bauxite from the Dajti Mine, Albania
Novák, Jiří Karel ; Minařík, Luděk ; Peza, Luftulla Hasan ; Melka, Karel
The accelerated chemical weathering of bauxite due to acid atmospheric deposition and breakdown of pyrite was simulated using short-termed laboratory acid leaching at 20 o C. Pyrite-bearing gibbsite-boehmitic bauxite giving rise to a number of questions concerning ecology was tested along with oxic boehmitic bauxite from the Dajti mine and that from Mali Korites (Mali Thate Mts., SE Albania). The leachte of pyrite-bearing and sulphate-producing bauxite is enriched in the following risk elements: Cd, Be, Zn, Ni, Co, and much less Cr, Cu, As, and Pb. Toxic soluble hydroxy-alumina ions may be also released into the aquatic environment, because of high concentration in output leachate (563 mg/l). In contrast, the leachates of oxic boehmitic bauxites commonly contain much lower concentrations of toxic elements with exception of Cu (Dajti mine) and Be (new occurence of Mali Korites).
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Cenozoické vulkanické série v západní části Českého masívu
Ulrych, Jaromír ; Novák, Jiří Karel ; Lloyd, F. E. ; Balogh, K. ; Hegner, E. ; Viereck-Götte, L. G.
The western part of the Ohře/Eger Rift is a geodynamically active area in the Alpine foreland. Associated Cenozoic alkaline volcanism, particularly that of Quaternary age, plays an important role in the seismic active region of the W Bohemia and Saxony and is accompanied by intensive manifestations of mantle degassing (CO2, He, N). Three Tertiary to Quaternary alkaline volcanic rock series were recognised there: 1. Early Oligocene to Early Miocene (31-20 Ma) in the Doupovské hory Mts. and western Ohře Riftu. 2. Middle to Late Miocene (16-8 Ma) associated with the Cheb-Domažlice Graben. 3. Pleistocene (0.43-0.26/0.11 Ma) associated with the Ohře Rift and Cheb-Domažlice Graben junction. On the basis of isotopic and geochemical data of the primitive mafic volcanics of all series the source of magmas is a sublithospheric HIMU mantle source.
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