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Zró nicowanie stratygraficzne lessów Lubelszczyzny

DOI: 10.2478/v10066-008-0006-9

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Abstract:

Loesses in the Lublin Upland occur in the form of several extensive patches enclosed with clear morphological boundaries. The thickness of the loesses is spatially and stratigraphically diverse. Vistulian loesses, occurring on the surface of the area, usually have the thickness within the range of 12-13 m. In the discussed area, there have also been preserved loesses from the Middle-Polish and the South-Polish Glaciations. The total thickness of differently aged loess and loess-like deposits may amount to 40 m. The differently aged loesses are separated by interglacial soils. In loess covers, there have been found interglacial soils and pedocomplexes from the Eemian Interglacial and early Vistulian Glacial (GJ1), Zbójno Interglacial (GJ3a), and Mazovian Interglacial (GJ3b), as well as Ferdynandów Interglacial soils (GJ4a, GJ4b) and Ma opolan Interglacial soils (GJ5). Loesses from individual stratigraphic levels are divided by interstadial soils into units of lower stratigraphic rank. In loess patches located in the vicinity of the Vistula valley, i.e., on the Na czów Plateau, the Urz dów Hills and in smaller patches of the Dobre, and the Wilko az and Kluczowice region, only Vistulian loesses have been found. No loesses of the Odranian Glacial have been observed there since these must have been stripped off and washed away in their entirety during the transgression of the Odranian ice-sheet, which had lobbed its way into the Vistula valley, reaching as far as Sandomierz. A similar situation can be observed on the Gie czewska Interfluve: only Vistulian loess, strongly sandified in places, occurs there in the neighbourhood of the River Wieprz valley. In the loess patch of the Grabowieckie Watersheds, the Horod o Plateau (Grz da Horodelska) and the Sokal Plateau (Grz da Sokalska), the stratigraphic differentiation of loesses is greater since, in places, loesses and loess-like deposits have been preserved here that come from glacials as old as the Nidanian, Sanian 1, Sanian 2, Liwiecian as well as Odranian and Wartanian Glacials. Also fully-formed Vistulian loesses occur here. The oldest loesses, i.e., older than the Odranian Glacial, have usually survived within deep negative subquaternary forms, where they are interbedded with paleosols of different stratigraphic rank and Mesopleistocene tills. Tills and paleosols constitute superb stratigraphic benchmarks, which together with other criteria of physico-chemical, palinological, and micromorphological nature as well as thermoluminescent dating, help specify the stratigraphy of these sediments. An essential role in the preservation potential of the original Mesopleistocene loess covers has been played by the relief of the area which limited the intensity of the erosive-denudative and exarative activities of the ice-sheet. In highly reliefed areas, Old Pleistocene loess covers have not been preserved or have been preserved in a residual form. Cases in point are the loesses of the Zamo Valley (Kotlina

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