Naslov
Trace metals and C and O stable isotope composition in the recent tufa from four karstic rivers in Croatia

Autori
Cukrov, Neven ; Kwokal, Željko ; Lojen, Sonja ; Vázquez Navarro, Juan ; Grabar, Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
33rd International Geological Congress, Abstract CD-ROM / - Oslo, 2008

Skup
33rd International Geological Congress

Mjesto i datum
Oslo, Norveška, 06.08.2008. - 14.08.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
trace metals; stable isotope; tufa; karst

Sažetak
The four carstic rivers are located in the Outer Dinarides carbonate platform. Two of them, Zrmanja and Krka, are major karstic river at the middle Croatian Adriatic coast, whereas other two, Krčić and Krupa, are their tributaries. The hydrological situation of the entire catchment is very complex and not yet fully explained. Tufa is precipitated on the entire course of those rivers, forming several up to 50 m high barriers and cascades in the river Krka, stretching over several 100 m in length. The uniqueness of these tufa barriers and waterfalls is base natural phenomenon of the "Krka" National Park, proclaimed in 1985. Anthropogenic influence in those rivers were observed only in the Krka river by monitoring concentrations of (Hg, Cd, Pb, Cu & Zn) in the river water during last 6 years, and is reflected also geochemical and isotopic anomalies in laminar precipitates found in the lower part of the Krka stream. Comparison of C and O stable isotope composition of water and sediments collected at and behind the barriers showed that tufa precipitation occurs in isotopic equilibrium only at the uppermost sampling station at the Krka river, where the temperature is relatively low (below 13°C) and stable throughout the year. The aim of the study was to compare environmental records obtained from the recent tufa. Tufas were sampled during July, 2007 and were analysed for concentrations of trace metals (Hg, Cd, Pb, Cu and Zn), as well as δ 18O and δ 13C. Stable isotope composition in carbonates from recent tufa varied over a range of values of several permil (δ 13C -10.7‰ to -7.86‰ VPDB ; δ 18O -8.21‰ to -7.03‰ VPDB). Concentrations of trace metals in the tufa (Hg 12.8-56.4 ng/g, Cd 223-779 ng/g, Pb 2.14-18.6 ng/g, Cu 2.06-37.3 ng/g and Zn 9.40-96.4 ng/g) show that anthropogenic activities, especially industrial, agriculture and war operations in this area (1990-1995) has small influence at the tufa precipitation.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

POVEZANOST RADA