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Preliminary results of 57Fe Mössbauer spectroscopy of metamict samarskite after one-hour high temperature annealing in argon

Malczewski D., Grabias A.

Nukleonika

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2017

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Vol. 62, No. 2

141--144

EN

The preliminary results of 57Fe Mössbauer spectroscopy and X-ray diffraction (XRD) of fully metamict samarskite dated at ~1500 Ma, which absorbed -dose of 6.5 × 1017 α-decay mg–1, are reported after one-hour annealing at 673, 873, 1173 and 1373 K in argon atmosphere. Metamict minerals contain radioactive elements that degrade their crystal structures over geological time. All the Mössbauer spectra obtained can be fitted to two quadrupole doublets assigned to Fe2+ and Fe3+ in octahedral positions. The relative contribution of Fe2+ (Fe2+/Fe) reaches a minimum of 0.10 at 1173 K.

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Identification of iron-bearing minerals in basalts and pillow lavas of the Kaczawa Mountains using 57Fe Mössbauer spectroscopy

Malczewski D., Jeleń M., Żaba J., Błachowski A., Ruebenbauer K., Dziurowicz M.

Nukleonika

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2017

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Vol. 62, No. 2

145--148

EN

The Kaczawa Mountains along with the Kaczawa foothill comprise a complicated geological unit that is called the Kaczawa metamorphic (Sudetes, SW Poland). The aim of our work was to identify the iron-bearing minerals in samples of basalts and pillow lavas from the Kaczawa metamorphic using 57Fe Mössbauer spectroscopy. Based on the preliminary results, the Fe3+/Fe2+ ratio in the samples was determined.

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Erratum to “Preliminary results of 57Fe Mössbauer spectroscopy of metamict samarskite after one-hour high temperature annealing in argon” [Nukleonika 2017;62(2):141-144]

Malczewski D., Grabias A.

Nukleonika

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2017

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Vol. 62, No. 4

311

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222Rn and 220Rn concentrations in soil gas of the Izera Massif (Sudetes, Poland) as a function of sampling depth

Malczewski D., Żaba J.

Geological Quarterly

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2017

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Vol. 61, No. 4

877--886

EN

This research presents soil gas 222Rn and 220Rn concentrations measured at 17 locations in the Izera Massif of southwest Poland. The average 222Rn concentrations at sampling depths of 10, 40 and 80 cm were 8, 78 and 224 kBq m–3, respectively. The average 220Rn concentrations for the same depths (10, 40 and 80 cm) were 6, 10 and 13 kBq m–3, respectively. Profiles of the concentrations versus depth can be fitted by exponential, linear and polynomial functions for soils developed on fault zones, above uranium mineral deposits, and above faulted uranium deposits, respectively. Soils developed on bedrock without fault zones or uranium mineralisation exhibit concentrations that follow a power function with an exponent of p<1.

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Laboratory measurements of natural radioactivity in selected igneous rocks of the Opava Mountains region

Dżaluk A., Malczewski D., Żaba J., Dziurowicz M.

Geology, Geophysics and Environment

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2015

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Vol. 41, no. 1

73--74

EN

The paper presents the results of the laboratory gamma-ray measurements of six igneous rocks from the Opava Mountains. The Opava Mountains are located in the Eastern Sudetes and represent their furthest eastern range. They run almost latitudinally along the Polish border with the Czech Republic. The Opava Mountains are mostly situated in the Czech Republic. Only a small fragment between Głuchołazy in the west and Prudnik in the east is situated in Poland (Janeczek et al. 1991). The study area is built of rocks of different ages and lithologies. The Opava Mountains belong to the western part of the Upper Silesia Block, which together with the Brno Block form a structure that is called the Brunovistulicum. The mountains consist of five structural stages: the Žulova Massif, the Desna Series, the Vrbno Series, the Andělská-Hora Formation and the Horn-Benešov Formation, which run longitudinally (Żaba et al. 2005). The activities of naturally occurring radionuclides were measured using a portable GX3020 gamma-ray workstation. The system is based on a high-purity germanium (HPGe) detector with a 32% relative efficiency and energy resolutions of 0.8 keV at 122 keV and 1.7 keV at 1330 keV. The activity concentrations of 40K varied from 519 Bq∙kg−1(paragneiss, Głuchołazy/Mikulice) to 1559 Bq∙kg−1(weathered granite, Sławniowice), while those of 228Ac (232Th series) from 7.2 Bq∙kg−1(weat hered granite, Sławniowice) to 70.6 Bq∙kg−1 (migmatitic gneiss, Nadziejów). The activities that were associated with 226Ra (238U series) ranged from 5.5 Bq∙kg−1(weathered granite, Sławniowice) to 52.2 Bq∙kg−1 (gneiss, Kamienna Góra). The measured activity concentrations were compared with the average activity concentration of 40K, 228Ac (232Th) and 226Ra (238U) for similar types of rocks reported in the world specialist literature. The average value of the activity concentrations of 40K for granites and gneisses equals 1000 Bq∙kg−1 (Van Schmus 1995, Eisenbud & Gesell 1997), which means that the measured value of granite in the Sławniowice quarry is significantly higher than the average one, whereas the activity concentration of paragneiss is almost two times lower than the average value of similar types of rocks. The activity concentrations of 228Ac (232Th) and 226Ra (238U) in measured rocks are comparable to the average values (70 Bq∙kg−1 and 40 Bq∙kg−1 respectively (Van Schmus 1995, Eisenbud & Gesell 1997). Only the activity concentrations of granite in the Sławniowice quarry are considerably lower than the average values for the typical ones because it is strongly weathered. The aim of this paper is to show the first experimental data concerning the activity concentrations of primordial radionuclides in the igneous rocks in the Opava Mountains.

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In situ measurements of natural radioactivity in selected igneous rocks of the Opava Mountain region

Dżaluk A., Malczewski D., Żaba J., Dziurowicz M.

Contemporary Trends in Geoscience

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2014

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Vol. 3, iss. 1

5--13

EN

In situgamma-raymeasurements of fourigneousrocksweretaken in the Opava Mountains (EasternSudetes, Poland). The activity of naturallyoccurringradionuclides was measuredusing a portable GX3020 gamma-rayspectrometryworkstation. The activityconcentrations of 40K varied from 914 ± 17 Bqkg-1 (gneiss, Kamienna Góra) to 2019 ± 37 Bqkg-1 (weatheredgranite, Sławniowice), whilethose of 232Th from 7.5 ± 0.6 Bqkg-1 (weatheredgranite, Sławniowice) to 68 ± 0.9 Bqkg-1 (migmatiticgneiss, Nadziejów). The activitiesassociated with 238U decayseriesranged from 10 ± 0.4 Bqkg-1 (weatheredgranite, Sławniowice) to 62 ± 1.6 Bqkg-1 (gneiss, Kamienna Góra). The resultswill be used in compilingRadiological Atlas of the Sudetes.

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57Fe Mössbauer spectroscopy of annealed metamict davidite

Malczewski D., Frąckowiak J., Galuskin E.

Nukleonika

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2007

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Vol. 52, supl. 1

81-84

EN

This paper reports preliminary results of 57Fe Mössbauer spectroscopy and X-ray diffraction (XRD) studies of metamict davidite samples (La,Ce,Ca,Th)(Y,U,Fe)(Ti,Fe,Mn)20(O,OH)38 after high temperature annealing in an argon atmosphere. The Mössbauer spectra show a gradual decrease of quadrupole splitting and line width values of an Fe3+ doublet with increasing annealing temperature. Rather unexpected feature of these spectra for an Fe2+ doublet is a considerable increase of the line width with progressive crystallinity and a simultaneous decrease of both quadrupole splitting and isomer shift values. Changes of the hyperfine parameters as a function of the annealing temperature appeared as sensitive indicators of the thermal recrystallization process of metamict davidite similar to metamict silicates.

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Promieniotwórczość naturalna skał paleozoicznych z rejonu Krzeszowic

Malczewski D., Badera J., Lizurek G., Mirkowski Z., Dorda J.

Przegląd Geologiczny

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2006

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Vol. 54, nr 9

815-822

EN

In this paper results of natural radioactivity of 40K, 208Tl, 212Pb, 212Bi, 214Pb, 214Bi and 228Ac in common rocks raw materials mined in the Krakow vicinity measured in situ using a portable gamma-ray spectrometry are presented. The study area occupies the SE edge of regional geologic unit called Krakow–Lubliniec Zone. Most Upper Paleozoic rocks exposed in this area like tuff, porphyry, limestone, dolomite, diabase and melaphyre have great economic importance and are used in building and road construction industry. The activity concentrations of 40K for the measured Paleozoic rocks ranged from 53 Bq/kg (Carboniferous limestone) to 3150 Bq/kg (Permian tuff). The activity concentrations associated with 228Ac (232Th) varied from about 7 Bq/kg (Carboniferous limestone) to 56 Bq/kg (Permian tuff), whereas activity concentrations of 226Ra (238U) ranged from 19 Bq/kg (Devonian dolomite) to 43 Bq/kg (Devonian limestone). Besides, the natural radioactivity of the Jurassic limestones (widespread in this region) was measured for comparision with Devonian and Carboniferous limestones.

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Promieniotwórczość naturalna wybranych skał krystalicznych bloku izerskiego

Malczewski D., Sitarek A., Żaba J., Dorda J.

Przegląd Geologiczny

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2005

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Vol. 53, nr 3

237--244

EN

Results of natural radioactivity of 40K, 208Tl, 212Pb, 212Bi, 214Pb, 214Bi, 228Ac and the fallout of 137Cs measured in situ in typical crystalline (both igne-ous and metamorphic) rocks of the Izera Block (Sudetes Mountains, southwestern Poland) using a portable gamma-ray spectrometry workstation are presented. The highest activity concentrations of 40K and 226Ra (238U series) were noted in laminated gneisses whereas the highest activity concentration of 228Ac (232Th series) is characteristic for Sn-bearing mica schists. The lowest activity concentrations of 40K, 228Ac and 226Ra refer to the basalts, flaser gneisses and Izera granites, respectively. The measurements carried out in the study area have shown relatively low level of 137Cs fall-out.

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Assessment of natural and anthropogenic radioactivity levels in rocks in the Krzeszowice area, Poland

Lizurek G., Malczewski D.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

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2004

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nr 1

111-112

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57Fe Mössbauer study of stilpnomelane and associated chlorite from Polish granite pegmatites

Malczewski D., Popiel E., Sitarek A.

Nukleonika

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2004

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Vol. 49,suppl.3

43-48

EN

This paper reports the results of 57Fe Mössbauer study of stilpnomelane K0.6Fe6(Si8Al)(O,OH)27 .2H2O from Żółkiewka (Lower Silesia, Poland). Stilpnomelane in paragenesis with chlorite, tourmaline, claevelandite and zeolites has been found in granite pegmatites in quarries at Żółkiewka. The samples of naturally weathered stilpnomelane and chlorite from the same fragment of rock were also studied. The Mössbauer spectrum of an untreated sample could be fitted to two Fe2+ doublets and two Fe3+ doublets. The Fe2+ doublets have similar isomer shifts, but they distinctly differ in values of quadrupole splittings. Ferric iron, octahedrally coordinated occurs in three different environments represented by two doublets. The first of them, assigned to combined M1 + M2 positions and the second one assigned to M3 site with parameters IS = 0.36 mm/s and QS = 2.07 mm/s is visible in the spectra up to 880°C. This doublet is characteristic of stilpnomelane and can be regarded as a "fingerprint" of this mineral. After heating at 200°C, the relative content of Fe2+, ÓFe2+/ÓFe, decreases to 0.22 what means a 50% decrease in comparison to the initial value observed in the untreated sample. At about 1000°C, complete breakdown of the stilpnomelane structure takes place and the Mössbauer spectrum consists of two sextets and two ferric doublets. Abnormally high content of Fe2+ in naturally weathered stilpnomelane (0.70) comparing to the untreated sample of stilpnomelane (0.45) indicates that the sample had to be subjected to hydrothermal processes operating locally. Almost the same contents of divalent iron and hyperfine parameters of Fe2+ and Fe3+ doublets in weathered stilpnomelane and associated chlorite suggest that the process of chlorite transformation into stilpnomelane seems to be very probable.

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Characterisation of amorphous state of REE2Fe2+Be2Si2O10 by spectroscopic methods.

Malczewski D., Skrzypek D., Molak A.

Archives of Materials Science

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2004

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Vol. 25, nr 4

561-571

EN

This paper presents 57Fe Moessbauer spectroscopy, electron paramagnetic resonance (EPR), transmission electron microscopy (TEM), X-ray diffraction (XRD), gamma-ray spectroscopy and dielectric permitivity spectroscopy studies of fully metamict gadolinite REE2Fe2+Be2Si2O10 from Ytterby (Sweden). X-ray and electron diffraction patterns of the sample show complete lack of long range order (LRO). 57Fe Moessbauer spectroscopy of the sample revealed only Fe3+ ions definitely located in octahedral coordinations, similar to thye crystalline structure of gadolinite. The EPR resonance spectrum is complete and its features corespond to Gd3+ and Mn2+ centers. The Gd3+ centers show low-symmetry of local crystal field and may be characterized by distribution of spin-Hamiltonian parameters such as: g-factor and fine-structure parameters. The temperature dependence of utensity proves that a fraction of gadolinium ions interact by superexchange type mechanism and reveals that these exchange interactions are of the antiferromagnetic type Mn2+ centers and the character of Mn2+ EPR spectra indicate that this spectra are atributed to isolated manganium ions. The AC conductivity exhibits thermally activated behavior above 420 K whereas the dielectric constant shows a step-like anomaly near 230 K.

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57Fe Mössbauer spectroscopy and X-ray diffraction study of gadolinites REE2Fe2+Be2Si2O10 from Lower Silesia (Poland) and Ytterby (Sweden)

Malczewski D.

Nukleonika

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2003

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Vol. 48,suppl.1

41-44

EN

This paper reports the results of 57Fe Mössbauer spectroscopy, X-ray diffraction (XRD) and gamma-ray spectroscopy studies of partially metamict gadolinites from Szklarska Poręba and Zimnik (Lower Silesia, Poland), a fully metamict gadolinite sample from Ytterby (Sweden) and a crystalline sample obtained after annealing of a fragment of the sample from Ytterby at 1373 K in an argon atmosphere. Both fully metamict and crystalline gadolinite show divalent iron exclusively in octahedral coordination. Changes of the amplitudes ratio of high energy to low energy absorption peaks from Fe2+ quadrupole doublets are strictly correlated with calculated absorbed alpha-dose and the metamictization stages of the gadolinite specimens. In this respect, one of the samples is in conflict with the estimated radiation dose based on age and radionuclide concentrations. In this case, Mössbauer spectroscopy shows that the sample had to be naturally annealed over geologic time.