The effect of geochemical evolution of AMD on mineral composition of stream sediments: preliminary study on Hadůvka stream, West-ern Moravia, Czech Republic.
| Authors | |
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| Year of publication | 2003 |
| Type | Article in Proceedings |
| Conference | Applied Environmental Geology in Central and Eastern Europe |
| MU Faculty or unit | |
| Citation | |
| Web | http://www.ubavie.gv.at/publikationen/Berichte/BE228.pdf |
| Field | Geochemistry |
| Keywords | acid mine drainage; secondary minerals; bottom sediment |
| Description | Results from X-ray diffraction have showed that all recently formed minerals are amorphous, nearly amorphous (without regular crystal lattice) or cryptocrystalline and occur in mixture of several phases. Thus this method seems to be unsuitable for characterization of such fresh sediments. Modelling made with the aid of The Geochemists Workbench suggested hypo-thetical presence of goethite, pyrolusite, calcite and kaoline. Coupled with sequential and silicate analyses, this hypothetical minerals have been taken as normative for further evalua-tion of bottom sediments. Natural Hadůvka stream sediments are characterized by low con-tent of Fe- and Mn-oxyhydroxides (3 to 4 %) and carbonates (0.X %). Inflow of AMD into the stream causes rapid rising of insoluble HFO (20 to 30 %), carbonates (20 to 30 %) and clay minerals (5 to 10 %) content, but maximum of carbonates is slightly later than that of HFO. Presence of Mn-oxydroxides is also higher in polluted water, but maximum of precipitation take place subsequently after maximum of HFO (few hundreds of meters downstream). Thus water lost about 90 % of total dissolved solids in first hundreds of meters. Long-term monitor-ing reveal seasonal variation of mineralogical composition of bottom sediments, when high-est contents of recently formed mineral phases are in first half of years. Multiyear trend is pointed at lowering of influence of AMD onto bottom sediment composition. |
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