Radiocarbon Dating of Calcareous Tufa: How Reliable Data Can We Expect?

Abstract

Systematic dating of tufa samples has been undertaken to establish achronology of tufa deposits in Plitvice National Park, Yugoslavia. We conclude thattufa samples give reproducible data within the time span of 40,000 years up torecent. The 14C/12C ratio of carbon in the ambient biosphere and hydrosphere gives adetailed picture of the distribution of carbon isotopes in the investigated system.Despite the susceptibility of calcareous material to ambient conditions in the hydrosphere,the original 14C composition of tufa has not been substantially changed. Avertical profile which was cut in tufa during pathway construction showed that thetufa isochrones run vertically in the investigated area. The vertical isochrones and the14C gradient were horizontal due to tufa build-up in Plitvice National Park whichoccurs on vertical escarpments that have been flooded. The relatively uniform radiocarboncontent of most tufa deposits indicates redistribution of radiocarbon duringthe formation period. While detailed stratigraphy is often obscured, a general chronologyof tufa deposits in the investigated area has been established.