Characterization of tufa from the Dinaric Karst of Croatia: mineralogy, geochemistry and discussion of climate conditions

Abstract

Tufa deposits from four separate occurrences in the Dinaric Karst of Croatia were characterized with respect to mineralogy, geochemistry and activity of radionuclides. Three of the specimens are of Holocene age, formed during Atlantic, Subboreal and present climate. Two locations (Plitvice Lakes and Krka River) have previously been studied. Two locations (Mrenica and Slunjčica rivers) have not attracted scientific research yet. The major mineral in tufa is calcite. Minor minerals are quartz and dolomite, depending on location. Geochemistry of selected stream sediments (f <63 mm) from the Dinaric Karst was presented for comparison with tufa. Provided statistically significant number of samples studied, the ratios 238 U/ 226 Ra, 238 U/ 232 Th and 137 Cs may provide tighter constraints on the paleoenvironment. It is suggested to be used in comparison of different world tufas. In general terms it is discussed a hypothesis that relates the occurrence of tufas to atmospheric pCO 2 and climate conditions. In addition, the needs for future multidisciplinary research on tufa formation are discussed, because there are several other important parameters dependent on climate, which still have to be studied.

New insights into biological influence on the geochemistry of freshwater carbonate deposits

“…The four systems remained supersaturated by a similar magnitude with respect to calcite at the end of the experiment (SI = 2.97, 2.37, 2.85 and 2.35 for Flumes 1-4, respectively). These values are comparable with those reported from analogous natural systems (Franciskovic-Bilinski et al, 2004).…”

“…tufas and travertines) is considered to be primarily driven by degassing of dissolved CO 2 (Andrews et al, 2000;Franciskovic-Bilinski et al, 2004), and our results give this concept partial support. During the first 2 weeks of the experiment detailed in Fig.…”

First systematic investigation of adults and second checklist of caddisflies of the Plitvice Lakes National Park with notes on research history, biodiversity, distribution and ecology

“…The Plitvice Lakes are a karstic hydrosystem with well defined hydrobiological (Golubić, 1969), hydrological (Petrik, 1958), mineralogical (Stoffers, 1975) and chemical (Srdoč et al, 1985;Frančišković-Bilinski et al, 2004) properties. They are located in a mountainous part of Croatia (Bertić et al, 2001) and have typical mountain climate features with cold winters and relatively hot summers.…”

Freshwater calcite precipitates from in vitro mesocosm flume experiments: a case for biomediation of tufas

“…A predominantly inorganic precipitation mechanism is still favoured by a few (Kano et al. , 2003; Franciskovic‐Bilinski et al. , 2004).…”