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The internal dose rate in quartz grains: experimental data and consequences for luminescence dating

Szymak Agnieszka, Moska Piotr, Poręba Grzegorz, Tudyka Konrad, Adamiec Grzegorz

Geochronometria

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2022

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Vol. 49, no. 1

9--17

EN

This work considers the impact of the internal alpha and beta dose rates in quartz grains obtained from sandy sediments on the results of luminescence dating. The internal dose rates reported here (ca. 0.01–0.21 Gy · ka−1) play a particularly important role, because of low (ca. 0.8–0.9 Gy · ka−1) or very low (ca. 0.4–0.6 Gy · ka−1) external dose rates. In these cases, the internal dose rates form a significant fraction of the total dose rates, often exceeding 10%. Ignoring this contribution would have made the considered luminescence ages artificially older. In our study, we measure both the internal alpha and beta contributions as the latter is usually neglected in the case of quartz. The dose rate measurements were performed using the innovative μDose system.

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Evaluating the effect of hydrofluoric acid etching on quartz grains using microscope image analysis, laser diffraction and weight loss particle size estimate

Poręba Grzegorz, Tudyka Konrad, Szymak Agnieszka, Pluta Julia, Rocznik Joanna, Świątkowski Jakub, Osadnik Rafał, Moska Piotr

Geochronometria

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2022

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Vol. 49, no. 1

1--8

EN

In this work we investigate the quartz etching process using hydrofluoric acid for trapped charge dating (TCD) applications. It is done using material collected from an active sand mine in Bełchatów Nowy Świat, central Poland. Approximately 20 kg of material was collected and prepared using routine procedures that are applied in TCD laboratories. The material was sieved using 180–200 μm meshes, and the selected fraction was etched for various time intervals. Sieved samples were etched for durations from 0 min up to 180 min and measured with microscope image analysis (IA), laser diffraction (LD), and mass loss which were used to estimate the depths of etching. Our results show statistical data on how non-uniform the etching process is. We estimate this as a function of etching time from IA, LD and mass loss. In our investigation, mass loss measurements with the assumption of spherical grains correspond to the decrease of radius of ca. 0.151 ± 0.003 μm ˑ min–1. In case of LD, a rough etch depth estimation corresponds to a range 0.06–0.18 μm ˑ min–1 with median at 0.13 μm ˑ min–1. Microscope IA gives a 0.03–0.09 μm ˑ min–1 with a median at 0.05 μm ˑ min–1. Moreover, quartz grains are fractured into smaller pieces while etching. It means that assumptions that are used in etch depth estimation from mass loss are not correct. They incorrect not only because grains are not spheres but also because the number of grains is not constant. Therefore, the etch depth estimated from mass loss might be overestimated. Using microscope IA we report etch depth ranges that might be used to roughly estimate the etch depth uncertainty.

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Luminescence dating procedures at the Gliwice Luminescence Dating Laboratory

Moska Piotr, Bluszcz Andrzej, Poręba Grzegorz, Tudyka Konrad, Adamiec Grzegorz, Szymak Agnieszka, Przybyła Aleksandra

Geochronometria

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2021

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Vol. 48, no.1

1--15

EN

The Gliwice Luminescence Laboratory (GLL) is a part of the Institute of Physics – Centre for Science and Education at the Silesian University of Technology, which has gradually evolved since the 1980s. To date, nearly 3500 samples have been dated using luminescence from materials such as ceramics, bricks, and sediments from archaeological and geological sites. Currently, the laboratory is equipped with four luminescence readers and three gamma spectrometers, allowing luminescence dating of approximately 300 samples annually for the needs of research projects. This article focuses on the laboratory procedures used in GLL to obtain luminescence ages. Recent improvements of the GLL's facilities and new equipment, as well as the performance spanning the Laboratory's 30 years of activity, are discussed in terms of obtained results and the involvement in national and international projects.

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Chronostratigraphy of Late Glacial aeolian activity in SW Poland – A case study from the Niemodlin Plateau

Moska Piotr, Jary Zdzisław, Sokołowski Robert Jan, Poręba Grzegorz, Raczyk Jerzy, Krawczyk Marcin, Skurzyński Jacek, Zieliński Paweł, Michczyński Adam, Tudyka Konrad, Adamiec Grzegorz, Piotrowska Natalia, Pawełczyk Fatima, Łopuch Michał, Szymak Agnieszka, Ryzner Kamila

Geochronometria

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2020

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Vol. 47, no.1

124--137

EN

The stratigraphy of Late Pleniglacial and Late Glacial fluvio-to-aeolian succession was investigated in two sites located at the Niemodlin Plateau, SW Poland. Lithofacial analysis was used for the reconstruction of sedimentary environments. An absolute chronology for climatic change and the resulting environmental changes were determined based on optically stimulated luminescence (OSL – nine samples) and radiocarbon (three samples) dating methods. Four phases of changes in sedimentary environments were established. The first depositional phase correlates with the Last Permafrost Maximum (24−17 ka) based on the type and size of the periglacial structures, which aggraded under continuous permafrost conditions. During 17.5−15.5 ka (upper Late Pleniglacial), a stratigraphic gap was detected, owing to a break in the deposition on the interfluve area. The second depositional phase took place during 15.5−13.5 ka. During this phase, the first part of the dune formation (Przechód site) and fluvio-aeolian cover (Siedliska site) was deposited. The sedimentary processes continued throughout the entire Bølling interstadial and Older Dryas. In the third phase (Allerød interstadial), soil formation took place. At the Siedliska site, palaeosol represented Usselo soil type, whereas at the Przechód site, there was a colluvial type of soil. The last phase (Younger Dryas) is represented by the main phase of dune formation in both sites. After the Younger Dryas, no aeolian activity was detected. High compliance with both absolute dating methods was noticed.