engleski

Chemical and textural composition of the Krka river tufa deposits from the Dinaric karst region of Croatia

Tufa deposits, carbonates precipitated by freshwater organic and inorganic processes, occur abundantly in the Krka National Park situated inside the Dinaric Karst region of Croatia, at past and present sites of waterfalls. Chemical, petrographic and statistical analyses were carried out on six tufa samples to relate their textural constituents and trace element composition to the geochemical processes operating within this diverse environment. Trace metal concentrations in carbonate phase were analysed by ICP-AES method, after a single extraction with 1M Na-acetate. The insoluble residue (I.R.) could resulted from the karstic weathering processes, ranging from 2.20 to 21.10% (median 3.70%), influencing the chemical composition of tufa samples. Generally, increased Fe, Mn, and I.R. levels are accompanied by decreased Sr and Mg levels, and vice versa.

tufa ; sequential extraction ; mossy encrustation ; trace metal correlation ; re-crystallisation ; Krka river

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