Hazai pleisztocén–holocén üledékek és talajok radioaktívelem-tartalmának jellemzői

Abstract

This paper considers the radioelement content of Pleistocene and Holocene sediments in Hungary. The evaluated data are from laboratory high-resolution gamma spectrometry measurements of sediments collected for luminescence
dating, and recent soils for the National Radiometric Base Network. Natural gamma ray logs of boreholes drilled on a loess area were also taken into account. U, Th and K content data indicate that the fine-grained sediments have a higher
radioelement content than the coarse sediments have. This could be caused primarily by the higher clay content of the fine-grained sediments. The radioelement content of palaeosols in loess sections is higher than that of loess layers. This
is probably due to the soil-forming processes: mainly the formation of clay minerals and iron-oxide-hydroxides, and the increase of the amount of organic matter. These adsorb the studied radioactive elements. Radioelement content of loesses
and recent soils from different areas reflects the local lithology or the petrology of the soil-forming rocks. The different soil-forming processes and the post-depositional changes are also important in the development of characteristic U, Th
and K content of the soil types and palaeosols. Sporadic radiometric data measured for luminescence dating are not suitable for the correlation of the loess sections. However, they can be well-correlated with the help of the natural gamma ray logs because the coeval loess and palaeosol layers show very similar shapes on the GR logs in the nearby boreholes.