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Spektrometryczne profilowanie gamma w odsłonięciach geologicznych : metody i przykłady zastosowania

Moskalewicz Damian

Przegląd Geologiczny

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2022

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Vol. 70, nr 11

806-- 815

EN

Handheld gamma-ray spectrometry (hGRS) is a valuable method for geological studies. It may be applied in correlations between well-logging and outcrop strata, enhance interpretations of sedimentological data, prospect radiogenic ores and geothermal resources, and identify radiogenic hazards for society. This paper aims to review and popularize one of the research methods based on a mobile device (hGRS) equipped with a BGO (bismuth germanium oxide) scintillator. The general concept of the research method is presented in this paper. The method's perspectives and limits based on reviewed literature. Advantages of hGRS include, e.g., low cost, short data acquisition time, the possibility of studying natural exposures, and a broad set of research applications. The main disadvantages comprise relatively modest resolution of acquired data and their difficult interpretation in complex geological formations. The review is backed by sample measurements performed in various geological exposures at Bornholm Island (Baltic Sea). Measurements comprised igneous rocks exposed in several quarries and sedimentary profiles near Liesti Valley and Muleby.

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Zastosowanie ziemskich izotopów kosmogenicznych w datowaniu glin lodowcowych : potencjał, ograniczenia i perspektywy badawcze

Tylmann Karol, Moskalewicz Damian

Przegląd Geologiczny

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2020

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Vol. 68, nr 10

764--773

EN

Determination of numerical age for glacial till is one of the most intriguing issues in glacial geology and geomorphology. Till layers are unequivocal evidence of ice sheets advances and retreats, and therefore they are very important for Quaternary palaeoclimatic reconstructions. Herein, we present a review dedicated to the methodology of glacial till dating with in situ cosmogenic nuclides. This relatively novel approach enables direct dating of deposition of till and its exposure after deglaciation. Getting reliable numerical age (in years) of till opens a new prospect for reconstructions of past glaciations and palaeogeographic studies. Despite some limitations of applying in situ cosmogenic exposure and burial dating, we argue that this technique may be successfully employed in studies of glacial deposits in Poland.

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Fluvial response to environmental conditions during MIS 4-3 : a sedimentary record at the Brześnica site, central-western Poland

Moskalewicz Damian, Tylmann Karol, Woźniak Piotr Paweł, Kopyść Natalia, Moska Piotr

Geological Quarterly

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2020

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Vol. 64, No. 4

915--930

EN

Fluvial deposits subjected to this study are exposed at the Brześnica site, in the south-western part of the Wielkopolska region in Poland, which was close to the ice-sheet limit during the Last Glacial Maximum (LGM). Sedimentological analyses, including lithofacies descriptions, palaeocurrent measurements, grain size and rounding analyses and heavy mineral compositions indicate that the fluvial deposits at Brześnica were deposited in braided river environment. The following fluvial sedimentary processes were inferred: (1) shallow, rapid flow alternating with waning flow, (2) infilling of erosional channels with fluvial sediments during flood events, (3) changes from supercritical to subcritical flows, and (4) shallow sheet floods. The results of OSL dating indicated sediment deposition ~65.2 ±1.5 ka, i.e. in MIS 4, that was here characterized by cold environmental conditions and a general shift from meandering to braided fluvial sedimentation style. This finding contrasts with accumulation/erosion phases interpreted previously in this region for that time interval; however, it is consistent with recent studies of fluvial systems functioning during MIS 5-2 and of factors responsible for sedimentation style.