SOIL ORGANIC CARBON DATING OF PALEOSOILS OF ALLUVIAL FANS IN A BLOWN SAND AREA (NYÍRSÉG, HUNGARY)
Botond Búró, Gábor Négyesi, Tamás Varga, György Sípos, Dávid Filyó, A. J. T. Jull, Mihály Molnár
Abstract
ABSTRACT The most widely used dating techniques in quaternary research are the radiocarbon ( 14 C) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for 14 C dating. In these cases, 14 C dating of bulk sediment may be used as a last resort. The major aim of the present study was to determine the reliability and limitations of the different fractions of the soil organic carbon (SOC) 14 C ages in the Nyírség blown-sand study area, in Hungary. Therefore, the low- and high-temperature combustions of SOC (LT-SOC and HT-SOC) 14 C age of fossil soils were compared with the charcoal ages from the same fossil soil layer, and their (LT-SOC, HT-SOC, and charcoal) age reliability was verified independently by applying OSL to the quartz fraction of the sediment samples. The 14 C data show variable agreement with OSL ages. Charcoal fragments were collected from some of the best material for 14 C dating and their ages are in agreement with the LT and HT-SOC 14 C ages and OSL data. The 14 C age LT-SOC gives a reliable, credible ages, which were confirmed by independent OSL measurements. If buried soils do not contain any other macroscopic remnants for 14 C dating, the LT-SOC 14 C ages can be used, in the case of the Nyírség study area. The LT-SOC, which is the younger fraction of the soil organic carbon, may be considered to represent the burial time of the fossil soil layer. The HT-SOC 14 C ages are sometimes unrealistically older than expected and cannot be considered to be reliable.