Naslov
Correlation of stable isotope composition of carbonate precipitated in the water under different conditions

Autori
Horvatinčić, Nada ; Sironić, Andreja ; Barešić, Jadranka

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

Izvornik
Book of Abstracts - ESIR Isotope Workshop XIII / Krajcar Bronić, Ines ; Horvatinčić, Nada ; Obelić, Bogomil - Zagreb : Institut Ruđer Bošković, 2015, 18-18

ISBN
978-953-7941-08-6

Skup
ESIR Isotope Workshop XIII

Mjesto i datum
Zadar, Hrvatska, 20.09.2015. - 24.09.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
stable isotopes; carbonates; fresh water

Sažetak
Composition of stable isotopes δ13C and δ18O of fresh carbonate precipitated in the waters of the Plitvice Lakes, δ13C of dissolved inorganic carbon (DIC) and δ18O of waters were measured at different locations with different conditions of precipitation. For this study we collected 3 types of carbonates (CaCO3) precipitate in the water: 1) suspended carbonate precipitated in 4 sediment traps, 2 – 10 m below the surface in 3 lakes, 2) CaCO3 precipitated on porous plastic pads submerged in the water (surface water) at 7 locations with different water flow rates (0 to 0.7 m/s), and 3) surface lake sediments (top ~40 cm) at the bottom of 3 lakes. Carbonates were collected in different seasons in period 2011 – 2013. We also measured a14C of CaCO3 from plastic pads. δ13C values for all carbonates are generally in the range from -10 ‰ to -6 ‰ which is typical for fresh water carbonates, but the difference between 3 types of carbonates was obvious. δ13C values for CaCO3 in 4 sediment traps were very uniform, with mean values from -8.5 ‰ to -7.5 ‰, showing stable conditions of carbonate precipitation in deep water. Difference between δ13CDIC and δ13Ccarb of the CaCO3 was between 2.8 and 3.9 ‰, indicating partial equilibrium conditions of precipitation. Narrow range of δ13C values of CaCO3 of surface lake sediment in 3 lakes (mean values from -9.5 ‰ to -9.0 ‰) showed similar stable conditions of CaCO3 precipitation, also in deep water. δ13C values of CaCO3 precipitated in surface waters showed variations from -10 ‰ to -4 ‰ depending on locations. At 2 out of 7 locations the higher δ13C indicated the mixing of authigenic CaCO3 and detrital CaCO3 of mineral origin. This was also indicated by a14C values in the same locations that were much lower (10 – 30 pMC) comparing with other 5 locations (70 – 80 pMC). δ18O values of surface water showed seasonal fluctuation (-10.9 to -9.8 ‰), while the δ18O values of CaCO3 showed more significant fluctuation depending on micro-location. Good correlation of δ18O of CaCO3 from 4 sediment traps with mean water temperature in period of precipitation was obtained. δ18O values of water and CaCO3 were used for estimation of temperature of carbonate precipitation. The best agreement of estimated with the real/measured temperatures at all deep waters/traps was obtained by the approach of Leng and Marshall [1]. The work was performed within the project with Plitvice National Park: Influence of environmental and climate changes on the biologically induced calcite precipitation in form of tufa and lake sediment at the Plitvice Lakes. [1] Leng M. J., Marshall J. D. Quaternary Science Reviews 23 (2004) 811–831.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Kemija

POVEZANOST RADA