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  • Author: Grzegorz Adamiec x
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Abstract

Absolute dating using luminescence methods is widely applicable in geology, geomorphology, palaeogeography and in archaeology in establishing ages of sediments and archaeological artefacts. By creating absolute time scales for different events in the history of Earth scientists are able to reconstruct changes in climate and environment in the past, and the history of colonization and development of culture.

Grain size is the most important loess lithologic property. Grain size composition depends mainly on factors connected with depositional processes (i.e. variety of source areas, distance from source areas, frequency and intensity of dust transporting winds). The influence of post depositional processes on changes in grain size composition seems to be of less importance with the exceptions for warm and long periods of intensive pedogenesis, which are favorable for formation of clay minerals. Therefore the grain size differentiation within thick loess sections may be used as a proxy record of climate changes during loess cover development.

Here we present results for 12 samples dated at the profile at Biały Kościół. Obtained OSL results in some cases are quite different as compared with the OSL and TL dates obtained during last 10 years by other authors and presented in previous publications relating to this loess profile.

Abstract

The identification of depositional conditions and stratigraphical position of glacigenic deposits in the Napęków area is important for the genetic and stratigraphical interpretation of Quaternary deposits in the central part of the Holy Cross Mountains, as well as for a revision of the course and extent of Middle Polish (Saalian) glaciations. These deposits comprise a series of diamictons which occur between sandy-gravelly deposits. Based on results of macro- and microscopic sedimentological investigations, analysis of heavy mineral composition, roundness and frosting of quartz grains, as well as OSL dating, this complex must have formed during the Odranian Glaciation (Drenthe, Saalian, MIS 6). Sandy-gravelly deposits are of fluvioglacial and melt-out origin. Diamictons represent subglacial traction till. Their facies diversity is a result of variations in time and space, complex processes of deposition and deformation, responsible for their formation at the base of the active ice sheet. This glacigenic depositional complex was transformed by erosion-denudation and aeolian processes in a periglacial environment during the Vistulian (Weichselian, MIS 5d-2).

Abstract

The presented work concerns a loess profile located in Tyszowce, in the eastern part of Poland on the Volyn Upland, close to the Ukrainian border. The investigated loess formation is well preserved and is characterised by clear stratigraphic units providing an opportunity to refine the loess chronostratigraphy in Poland. In the paper, we present luminescence ages of loess from the last glacial cycle in SE Poland (up to about 100 ka) together with seven radiocarbon ages. Twenty-one samples were collected and dated using infrared (post-IR IRSL) and blue light stimulated luminescence dating. Two fractions were used, namely polymineral fine grains (4–11 μm) and medium sized quartz grains (45–63 μm). The obtained luminescence ages show very good agreement of both methods in relation to loess deposits, however for the fossil soil units the post-IR IRSL method yields older ages. Radiocarbon dates also confirm luminescence chronostratigraphy for younger units. Moreover, the luminescence results are supported by detailed analyses of grain size distribution, carbonate content and magnetic susceptibility variations allowing to create a comprehensive picture of chronological evolution of this site.

Abstract

Loess formations in Poland display a close relationship with cooling and warming trends of the Northern Hemisphere during the Pleistocene. Loess sequences sensitively record regional palaeoclimatic and palaeoecological changes. The Złota loess profile (21°39’E, 50°39’N) provides a unique opportunity to reconstruct climate conditions in the past in this part of Poland. This continuous sequence of loess and palaeosol deposits allows to distinguish between warmer and more humid climate which is favourable for soil development and much colder and dry periods which are conducive to loess accumulation. The silty and sandy aeolian material originates mainly from weathered rock surfaces affected by frost shattering or from glaciofluvial/fluvial deposits of river flood plains. In Poland, loess and loess-like formations occur in the southern part of the country, mostly in the south polish uplands, i.e. in the Lublin, Sandomierz, and Cracow Uplands. We used different techniques to establish a chronological framework for this site. 21 samples for luminescence dating were collected from the investigated loess profile in Złota. Infrared post-IR IRSL dating method was applied to the polymineral fine grains (4–11µm). The dating results are accompanied by detailed analyses of the geochemical composition, organic carbon and carbonate. Also, analysis of magnetic susceptibility and grain-size distribution were investigated. Based on such a large stratigraphic dataset an age-depth model using OxCal has also been constructed for this site.

Abstract

Results of OSL dating and sedimentary studies from the profile of the low alluvial terrace of the middle Warta River are presented. The samples were dated using the single-aliquot regenera-tive method. Dating was used to establish a timing of the Weichselian Late Glacial events in the river valley environment. Stable conditions on the floodplain are expressed by the deposition of organic-rich series radiocarbon dated at 12 900-12 600 cal BP and 11 600-10 770 cal BP. Samples for OSL dating were collected from the mineral material deposited during the intensification of flood events during the Weichselian decline. The results obtained for the alluvia range from 12.78 ± 0.62 ka b2k to 14.33 ± 0.74 ka b2k. Sedimentological criteria allowed to distinguish between particular flood events. Overestimation of OSL ages is probably a result of rapidity of environmental changes in that time.

Abstract

A set of 121 radiocarbon and OSL dates has been compiled from the Upper Dnieper River and tributary valleys, Western European Russia. Each date was attributed according to geomorphic/sedimentological events and classes of fluvial activity. Summed probability density functions for each class were used to establish phases of increasing and reducing fluvial activity. The oldest detected reduction of fluvial activity was probably due to glacial damming at LGM. Within the Holocene three palaeohydrological epochs of millennial-scale were found: (1) high activity at 12,000–8,000 cal BP marked by large river palaeochannels; (2) low activity at 8,000–3,000 cal BP marked by formation of zonal-type soils on -floodplains; short episodes of high floods occurred between 6,500—4,400 cal BP; (3) contrasting hydrological oscillations since 3,000 cal BP with periods of high floods between 3,000–2,300 (2,000) and 900–100 cal BP separated by long interval of low floods 2,300 (2,000)-900 cal BP when floodplains were not inundated — zonal-type soils were developing and permanent settlements existed on floodplains. In the last millennium, four centennial-scale intervals were found: high flooding intervals are mid-11–mid-15th century and mid-17–mid-20th century. Intervals of flood activity similar to the present-day were: mid-15–mid-17th century and since mid-19th century till present. In the context of palaeohydrological changes, discussed are selected palaeogeographic issues such as: position of the glacial boundary at LGM, role of changing amounts of river runoff in the Black Sea level changes, floodplain occupation by Early Medieval population.