Radiocarbon dating of calcareous tufa; how reliable data can we expect?.

Abstract

Systematic dating of tufa samples has been undertaken to establish a
chronology of tufa deposits in Plitvice National Park, Yugoslavia. We conclude that
tufa samples give reproducible data within the time span of ≈ 40,000 years up to
recent. The 14C/12C ratio of carbon in the ambient biosphere and hydrosphere gives a
detailed 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. A
vertical profile which was cut in tufa during pathway construction showed that the
tufa isochrones run vertically in the investigated area. The vertical isochrones and the
14C gradient were horizontal due to tufa build-up in Plitvice National Park which
occurs on vertical escarpments that have been flooded. The relatively uniform radiocarbon
content of most tufa deposits indicates redistribution of radiocarbon during
the formation period. While detailed stratigraphy is often obscured, a general chronology
of tufa deposits in the investigated area has been established.