HOLIVAR2006 Abstracts
Ice in caves: a valuable tool for Holocene palaeoclimatic reconstructions.
A. Perşoiu1, B.P. Onac1,2, Z. Kern3 and I. Forizs4
1"Emil Racoviţă" Institute of Speleology, Clinicilor 5, Cluj Napoca, Romania
2Karst Research Group, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, USA
3Faculty of Geography, "Eotvos Lorand" University, Pázmány Péter sétány 1/C, Budapest, Hungary
4Institute for Geochemical Research, Hungarian Academy of Sciences, Budaörsi út 45, Budapest, Hungary
Contact: A. Perşoiu (persoiu@hasdeu.ubbcluj.ro)
Several caves (i.e., Scărişoara, Focul Viu and Borţig) in the Apuseni Mountains, Romania host large ice accumulations (up to 100,000 m3), dated by means of AMS 14C and pollen assemblages to about 3,500 years old (Pop and Ciobanu 1950, Holmlund et al. 2005, Citterio et al. 2005). The ice bodies have been accumulated through complex freezing and melting processes of waters that seeped into the cave. This process enabled the development of a series of ice and sediment layers, recording both past evolution of the ice block and the outside climatic conditions, which led to the ice accumulation.
Preliminary studies show the layered ice and sediment deposits in caves are potential archives that record high resolution palaeoclimate signals (Şerban and Racoviţă 1987). Recently, we have started a complex investigation of these caves in order to reconstruct past Holocene changes in climate parameters in this part of Europe. A first step in this approach is to decipher the potential perturbation of the climatic signal in the underground environment; mainly the one recorded by oxygen and hydrogen stable isotopes in water. Thus, a combination of stable isotopes measurements on rainfall, cave drip water, and ice was initiated. Along with these, detailed measurements of ice and sediment layers, long term monitoring of ice dynamics and temperature variations were used in order to establish a link between physical and chemical properties of ice and external climatic controllers of its variations. Historical data and tritium values were used in order to infer the age of the uppermost layers of ice used in this preliminary study.
The results obtained and presented here, suggest that 1) ice accumulations in caves respond in a more complex way to external climatic forcing than outside glaciers, 2) ice accumulations in caves record well-structured climatic signals, and, if correctly interpreted, they can be valuable tool in reconstructing past climates, and 3) a decreasing trend of precipitation values and a slow increase of air temperature can be inferred for the past 150 years.
Holmlund, P., Onac, B.P., Hansson, M., Holmgrem K., Morth, A., Nyman, M., Persoiu, A., 2005. Assesing the palaeoclimate potential of cave glaciers: the example of the Scarisoara Ice Cave (Romania). Geografiska Annaler, 87A (1), 193–201.
Pop, E., Ciobanu, I., 1950. Analize de polen în ghiaţa de la Scărişoara. Analele Academiei R.P.R., Seria Geologie, Geografie, Biologie. Tom 3, mem. 2, 23–46.
Şerban, M., Racoviţă, G., 1987. Sur l'information paleoclimatique comprise dans le depot souterrain de glace de la Grotte de Scarisoara (Monts de Bihor) et sa valorisation pour une prognose de long terme. Theoretical and Applied Karstology, 3, 133–142.
Citterio, M., Turri, S., Perşoiu, A., Bini, A., Maggi, V., 2005. Radiocarbon ages from two ice caves in the Italian Alps and the Romanian Carpathians and their significance. In Mavlyudov, B.R. (Ed.), Glacier Caves and Glacial Karst in High Mountains and Polar Regions, pp. 87–92.
Aurel Persoiu is PhD student at University of Cluj, Faculty of Geology, and research assistant at "Emil Racoviţă" Institute of Speleology, Cluj Napoca. His research interests include glaciology, climatology, and speleology.