Naslov
Assessment of the hydrological behavior in Croatian cave environments

Autori
Lončar, Nina ; Surić, Maša ; Lončarić, Robert ; Buzjak, Nenad

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

Skup
14th International Congress of the Geological Society of Greece

Mjesto i datum
Solun, Grčka, 25.05.2016. - 27.05.2016

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
cave monitoring, cave microclimate, dripwater, stable isotopes, hydrological settings, Croatia

Sažetak
There are many systematic studies of stable isotopes in speleothems used to get proxy records of past climate changes in the Mediterranean region, as well as in Europe. This research emphasizes the importance of understanding cave atmosphere and hydrology in order to select suitable stalagmites for paleoclimate analysis. Since the isotope composition of the speleothem depends on the cave drip water content, which itself reflects soil and atmospheric settings we performed interannual monthly cave monitoring. Microclimate elements (air temperature and relative humidity) were measured and drip water and rain is collected in three Croatian caves during the 1-year period. The aim was to evaluate the influence of parameters such as temperature and rainfall amount on variability of oxygen isotope ratios and to determine potential sites for further paleoclimate studies. Moreover, we focused on caves on various altitudes (Strašna peć Cave on Dugi otok Island (70 m a.s.l.), Manita peć Cave in Velika Paklenica canyon (Velebit Mt, 570 m a.s.l.) and Spilja u Zubu Buljme Cave (Velebit Mt, 1305 m a.s.l.) to estimate contemporary regional and local influences of Atlantic and Mediterranean air masses and differences between coastal and continental, and between low- and high-altitude sites. Altitude effect was noted both in precipitation and in dripwater isotopic composition. Dripwater isotopic values cluster along the local meteoric water line (LMWL), whereas, in spite of the altitude difference, Manita Peć cave resembles the Strašna peć Cave record both by the slope and intercept. Both caves recorded low temperature variations and stable cave environments. Recorded dripwater intensities showed different hydrological regimes, while drip sites showed stable discharge mode with weak response to the rain events. The highest Spilja u Zubu Buljme Cave significantly differs from abovementioned caves by quite large temperature amplitude (5.3 °C), the lack of recent carbonate precipitation and expressed altitude effect on isotopic composition of rainwater. Such results indicate that Strašna peć and Manita peć caves are suitable paleoclimate study sites regarding cave climate and drip hydrological settings. We presume that speleothem calcite in these cave has been precipitated in isotopic equilibrium with dripwater which is crucial for accurately interpreting climate proxies contained within individual stalagmites.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Interdisciplinarne prirodne znanosti, Geografija

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