Naslov
Interglacial growth of tufa in Croatia

Autori
Horvatinčić, Nada ; Čalić, Romana ; Geyh, Mebus A.

Izvornik
Quaternary Research (0033-5894) 53 (2000); 185-195

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

Ključne riječi
karst; tufa; Plitvice Lakes; Krka; radiocarbon dating; U-Th dating

Sažetak
Tufa samples from the Krka River area in Croatia were dated by 14C and 230Th/234U methods. The study area is situated in the karst region of the southern Dinarides. 14C ages of 40 tufa samples collected at the waterfalls coincide with the early Holocene interglaciation, up to 6000 14C yr B.P. Comparison of conventional 14C dates of Holocene tufa and those of speleothems in the Dinaric Karst shows that speleothem formation started several thousand years earlier than tufa growth. Samples of old tufa deposits from the Krka River (17) and Plitvice Lakes (12) area and speleothem samples from caves in Dinaric Karst (5) yield 34 230Th/234U dates, most of which cluster around interglacial marine delta18O stage 5 (21). Eight of 13 older dates belong to interglacial stages 7 and 9; only five dates fall within the stage 6 and 8 glaciations. 230Th/234U dates of speleothems and tufa samples from central Europe have indicated that these were formed preferentially during warm and humid interglacial and interstadial periods, and it appears that this is true of southern Croatia as well. Stable isotope (delta13C, delta18O) analyses of 40 tufa samples from the Krka River area were compared with stable isotope analyses of tufa from the Plitvice Lakes area. The delta13C values for both locations are similar and range from -10 to -6 ‰, indicating similar conditions of tufa formation. A systematic difference between the delta18O values of tufa in these two areas reflects the regional distribution of the oxygen composition of the precipitation.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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