Naslov
Early and mid-Holocene environmental conditions in the eastern Adriatic recorded in speleothems from Mala špilja Cave and Velika špilja cave (Mljet island, Croatia)

Autori
Lončar, Nina ; Bar-Matthews, Miryam ; Ayalon, Avner ; Surić, Maša ; Faivre, Sanja

Izvornik
Acta carsologica (0583-6050) 46 (2017), 2/3; 229-249

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Holocene, speleothem ; stable isotopes ; Eastern Adriatic, Croatia

Sažetak
This study presents high resolution oxygen and carbon isotopic record of two U-Th dated stalagmites from the Eastern Adriatic caves. The stalagmites were collected from Mala špilja and Velika špilja caves situated on Mljet Island in the southern part of the Croatian Adriatic. Dripwater samples were collected from Medvjeđa špilja, Strašna peć, Špilja u Vrdolje, Kraljicina spilja, Velika špilja and Mala špilja caves. All caves formed in well- stratified Cretaceous limestones. The average value of deuterium excess of the dripwater is 9.3‰, indicating that the atmospheric conditions over the Atlantic Ocean have greater influence on the isotopic composition precipitation in the Adriatic region than the Eastern Mediterranean Sea. The longest isotopic record of the speleothems is of stalagmite MSM- 1 from Mala špilja Cave dated from 119.2 ±3.3 ka to 5.6±0.6 ka, although deposition was not continuous. During the Holocene the speleothem grew between 7 ka and 4 ka. That interval is characterized by several δ18Oc and δ13Cc fluctuations reflecting changes in the environment. Superimposed on these fluctuations, there is an increasing trend in the 7.0-6.5 ka interval, evident in elevated δ18O values, which primarily refers the trend to drier conditions in the eastern Adriatic, which were occasionally interrupted by wet intervals. Humid conditions are particularly pronounced by low δ18Oc and δ13Cc values of speleothem MSM-1 between 7.3 and 6 ka, as a reflection of increased precipitation and lower temperatures. The transition to today's Mediterranean climate (Cs) occurred between 6 ka and 5 ka, while the driest conditions are recorded at ~4.7 - 4.2 ka. Comparisons between the eastern Adriatic δ18Oc and δ13Cc records of the speleothem from Mala špilja Cave (MSM-1) and Velika špilja Cave (Mljet Island) with Soreq Cave (Israel) and Corchia Cave (Italy) together with other proxies such as lake sediments demonstrate that the speleothems from the Eastern Adriatic caves record the local and the regional climatic changes.

Izvorni jezik
Engleski

Znanstvena područja
Interdisciplinarne prirodne znanosti, Geografija

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