SOIL ORGANIC CARBON DATING OF PALEOSOILS OF ALLUVIAL FANS IN A BLOWN SAND AREA (NYiRSeG, HUNGARY)

The most widely used dating techniques in quaternary research are the radiocarbon (C-14) and optically stimulated luminescence (OSL) dating methods. In some environments, the investigated sediments do not contain enough material for C-14 dating. In these cases, C-14 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) C-14 ages in the Nyirseg blown-sand study area, in Hungary. Therefore, the low- and high-temperature combustions of SOC (LT-SOC and HT-SOC) C-14 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 C-14 data show variable agreement with OSL ages. Charcoal fragments were collected from some of the best material for C-14 dating and their ages are in agreement with the LT and HT-SOC C-14 ages and OSL data. The C-14 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 C-14 dating, the LT-SOC C-14 ages can be used, in the case of the Nyirseg 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 C-14 ages are sometimes unrealistically older than expected and cannot be considered to be reliable.