The Basis of the Study of the Age of the Holocene Diluvium on Loess Areas of Polish Highlands

Large part of slope sediments (pediment) which are the effect of water induced soil erosion in the loess areas of Polish Uplands, has a close relationship with pre-historical, historical and "present" agricultural activity. The sediments accumulated in different periods are often separated by fossil soils. These soils are correlated with the periods of relinquishment of agricultural land use in a given area. A precise dating of the cycles of fossil soil formation is practically impossible. Therefore it is important to gain a possibility to establish the age of sediments between old fossil soils corresponding with the phases of soil erosion. The organic material in the floor or roof of deposits permitting a ¹⁴C dating is very seldom. This is why attempts were made to use the OSL method to date mineral parts of slope sediments. In connection with pedological and sedimentological methods, the OSL method makes it possible to give some information about the age of pre-historical and historical phases of intensive soil erosion. In order to date sediments accumulated during the last 50 years, the method based on measurement of ¹³⁷Cs isotope in products of soil erosion is used. This paper shows some examples of the application of ¹⁴C, OSL and ¹³⁷Cs methods in some selected research sites. In each case there is a discussion of limitations of the methods used.