engleski

Response of karst sediments to the atmospheric 14C bomb peak

The global atmospheric 14C bomb peak from 1963 is reflected in 14C activity of natural archives like tree rings, speleothems, corrals, sediments, etc. The attenuation and time delay of the peak in the archives compared to the atmospheric one can be used as a tool to study the carbon cycle of interest. The sediment cores from lakes Kozjak, Prošće, Gradinsko and Kaluđerovac from the Plitvice Lakes, karst area in Croatia, were retrieved in two sampling campaigns in 2003 and in 2011 on different locations and different lake depths. Some results of 14C activity in the sediment cores dated by 210Pb and 137Cs have already been reported. Here we present new results for the Lake Kaluđerovac and Lake Kozjak cores collected at the deepest points of the lakes, dated by 210Pb. In addition, 14C activity of laminated tufa that grew from 1979 to 2005 on a wooden pillar immersed in the Korana River is also presented. The 14C bomb-peak reflection is observed in carbonate and organic fractions of the sediment cores from the middle of lakes, and also in carbonate fraction of the laminated tufa, with attenuation and delay ranging from 28 to 36 years. The intensity of attenuation and delay compared to the atmospheric bomb peak in the laminated tufa and sediments will be discussed in relation with the lakes size and the sampling location.

karst sediments ; atmospheric 14C bomb peak

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