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Depositional conditions on an alluvial fan at the turn of the Weichselian to the Holocene – a case study in the Żmigród Basin, southwest Poland

Zieliński P., Sokołowski R. J., Fedorowicz S., Woronko B., Hołub B., Jankowski M., Kuc M., Tracz M.

Geologos

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2016

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Vol. 22, No. 2

105--120

EN

Presented are the results of research into the fluvio-aeolian sedimentary succession at the site of Postolin in the Żmigród Basin, southwest Poland. Based on lithofacies analysis, textural analysis, Thermoluminescence and Infrared-Optical Stimulated Luminescence dating and GIS analysis, three lithofacies units were recognised and their stratigraphic succession identified: 1) the lower unit was deposited during the Pleni-Weichselian within a sand-bed braided river functioning under permafrost conditions within the central part of the alluvial fan; 2) the middle unit is the result of aeolian deposition and fluvial redeposition on the surface of the fan during long-term permafrost and progressive decrease of humidity of the climate at the turn of the Pleni to the Late Weichselian; 3) the upper unit accumulated following the development of longitudinal dunes at the turn of the Late Weichselian to the Holocene; the development of dunes was interrupted twice by the form being stabilised by vegetation and soil development.

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Uncertainties on the luminescence ages and anomalous fading

Zink A.

Geochronometria

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2008

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Vol. 32

47-50

EN

It is well known that some minerals give underestimated luminescence ages due to anomalous fading. The anomalous fading follows a logarithmic decay law characterized by its slope, the socalled fading rate or g-value. Using the fading rate, Huntley and Lamothe (2001) suggested some correction for the fading underestimation of young samples (<40-50 ka). For polymineral fine grains, we observe a fading rate of 0-4%/decade for TL and BL-OSL and 4-6%/decade for IR-OSL. Extending the laboratory observation to archaeological age, the underestimation on the age for 10 ka is estimated to a mean of 5% for TL, 10% for BL-OSL and 45% for IR-OSL. Due to the non-linearity of the Huntley and Lamothe's fading correction, the contribution of the fading to the total uncertainty is estimated by a Monte-Carlo simulation. The inference on dating shows that the uncertainty on the anomalous fading can be a significant term of the combined uncertainty on the age, even for low fading rates.

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Datowanie luminescencyjne osadów czwartorzędowych - teoria, ograniczenia, problemy interpretacyjne

Bluszcz A.

Zeszyty Naukowe. Matematyka - Fizyka / Politechnika Śląska

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2000

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z. 86

3-104

PL

Datowanie luminescencyjne jest wykorzystywane w geologii od połowy lat 1960 i, zwłaszcza w ostatnim okresie, dzięki rozwojowi nowych metod i wprowadzeniu automatycznej aparatury można mówić o prawdziwym zalewie wyników datowania różnych osadów. Również w Polsce, gdzie działają cztery laboratoria wykonujące datowania metodami TL i OSL, liczbę datowań szacuje się na tysiące. Wydaje się jednak, że wśród większości użytkowników brak jest wiedzy na temat podstaw samej metody, a zwłaszcza jej ograniczeń, które rzutują na możliwości interpretowania uzyskanych rezultatów. Prezentowana praca stara się wypełnić te braki i adresowana jest przede wszystkim do szerokiego grona przyrodników już wykorzystujących lub zamierzających korzystać z możliwości luminescencyjnych metod datowania. Praca przedstawia fizyczne podstawy metody i zasadnicze zagadnienia związane z pomiarami luminescencji, dawek pochłoniętych i mocy dawek - to jest wielkości, których wartości są niezbędne do określenia wieku luminescencyjnego. Jednak większy nacisk położono na ograniczenia i niepewności wyników wynikające z samych pomiarów, jak i możliwych odstępstw od założeń, z których korzysta metoda, w rzeczywistych przypadkach. Duża część pracy została poświęcona analizie uzyskanych rezultatów i możliwości ich interpretacji. Tezy stawiane przez autora zostały zilustrowane za pomocą 160 wyników datowania prób 7 stanowisk, w większości (132 daty) wykonanych przez autora. Niezależnie od tych przykładów przedstawiono w pracy analizę i interpretację dużego zestawu dat TL otrzymywanych dla próbek lessu, obejmującego 457 wyników otrzymanych w wielu laboratoriach na świecie. W załączonych na końcu dodatkach przedstawiono zasady pobierania prób osadów przeznaczonych do datowania metodami luminescencyjnymi, oraz podstawowe informacje o procedurach laboratoryjnych stosowanych w Laboratorium Datowania Luminescencyjnego Zakładu Zastosowań Radioizotopów Instytutu Fizyki Politechniki Śląskiej w Gliwicach.

EN

Luminescence dating has been applied in geology for about 35 years and, especially in a recent period, due to development of new methods and with an advent of automatic measurement equipment we may see a real flood of new dating results obtained for different sediments. Also in Poland, where four laboratories date geological samples by TL and OSL methods, the total number of dates to several thousands. It seems however, that there is a gap between the knowledge of most users of dating results about the method and its actual deficiencies that limit possibilities of interpretation of obtained results. The present work is aimed at filling this gap and has been addressed first of all to a wide range of natural scientists, who already apply or plan to apply luminescence dating in their work. The work presents a physical basis of the method and fundamental problems related to measurements of luminescence, absorbed dose and dose-rate - that is those quantities, which values are necessary to determine a luminescence age. Still more stress has been applied to limitations and uncertainties of results resulting from measurement procedures as well as from possible departures from assumptions the method bases on, which occur in real cases. A substantial part of the work has been devoted to an analysis of obtained results and to possible interpretations. The theses put forward by the author have been illustrated by means of 160 dating results obtained for samples from 7 sites, in most cases produced by him (132 dates). Intependently from these examples, the work presents an analysis and interpretation of a large set of 457 TL dates obtained for loess samples in different laboratories. Two Appendices contain additional information concerning collecting sediment samples for dating by luminescence methods, and laboratory procedures that are applied in the Luminescence Dating Laboratory of the Department of Radioisotopes of the Institute of Physics, Silesian University of Technology in Gliwice.

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New methods of the luminescence dating in Gliwice laboratory

Stypa Katarzyna, Bluszcz Andrzej

Geologos

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2000

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Vol. 5

107--112

EN

After many years of experience with multiple aliquots method using both thermoluminescence and, more recently, optically stimulated luminescence it become possible to introduce a new, single aliquots method. The method enables determining the absorbed dose using one single portion of the sample. This eliminates many problems such as properties variation among individual aliquots of the same sample. It also makes possible to date even very small samples. The paper describes the method and procedures recently introduced in Luminescence Dating Laboratory in Gliwice in comparison to those being successfully used for a routine dating.

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Combined OSL and TL dating of young sediments - possibilities for new interpretations

Bluszcz Andrzej

Geologos

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2000

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Vol. 5

113--121

EN

This paper presents examples of application of combined OSL and TL dating to samples from two different sedimentary environments that usually give rise to a number of interpretation problems. The presented method provides means of controlling the effectiveness of bleaching of grains during depositional processes and consequently enables deducing conditions and duration of weathering and transport processes.