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Zastosowanie ziemskich izotopów kosmogenicznych 10Be i 26Al w badaniach geologicznych – zarys metody oraz stan badań w Polsce

Sobczyk A.

Biuletyn Państwowego Instytutu Geologicznego

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2016

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nr 466

279--290

PL

Celem niniejszego tekstu jest przybliżenie i wstępne zaznajomienie z podstawami metody datowania opartego na izotopach kosmogenicznych, przegląd głównych kierunków badawczych realizowanych przy jej użyciu oraz omówienie aktualnego stanu badań w Polsce. Do najczęściej wykorzystywanych izotopów kosmogenicznych należą 3He, 10Be, 14C, 21Ne, 26Al oraz 36Cl, które znajdują szerokie zastosowanie w badaniach form rzeźby oraz rekonstrukcji procesów geologicznych. Dzięki temu umożliwiają systematyzację geochronologiczną dla późnego kenozoiku, co jest szczególnie ważne tam, gdzie tradycyjne metody badawcze okazują się niewystarczające. Metoda ta cechuje się szerokim potencjałem analitycznym umożliwiając m.in. datowanie wieku ekspozycji różnych form powierzchni terenu, określanie współczynników denudacji i erozji, czy też szczegółową rekonstrukcję chronologii zlodowaceń.

EN

The aim of this paper is to present a methodological introduction into cosmogenic radionuclides dating, summarizing the main research objectives, and an overview of the state of studies in Poland. Cosmogenic nuclides 3He, 10Be, 14C, 21Ne, 26Al and 36Cl are among the most common ones, being widely applied to analyses of geomorphological features and reconstructions of geological processes. Thereby they allow geochronological systematization of the Late Cenozoic, being of primary importance if traditional research methods fail. This approach has broad analytical potential for, i.e., dating of exposure history of different morphological features, estimation of denudation and erosion rates, as well as detailed reconstruction of glacial chronology.

2

The meteorite fall near Boumdeid, Mauritania, from September 14, 2011

Buhl S., Toueirjenne C., Hofmann B., Laubenstein M., Wimmer K.

Meteorites

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2014

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Vol. 3, No. 1-2

5--18

EN

On the evening of September 14, 2011 at 21:00 GMT a bright bolide was observed by hundreds of eyewitnesses in the area north and west of the town of Kiffa, in the department of Assaba, in south Mauritania. A terminal fragmentation and sound phenomena were observed near the end point of the trajectory. At least one mass of 3.5 kg was observed to impact and recovered the morning after the fall near Boumdeid (or Bou Mdeid), around 60 km north of Kiffa. Subsequently a large number of eyewitness accounts were recorded and mapped by GPS. The present paper provides a scenario for the trajectory of the Boumdeid (2011) meteorite based on the available parameters and wind data at the relevant altitudes. In addition the paper presents the results of the mineralogical and chemical analysis of the recovered meteorite which is consistent with a classification as ordinary chondrite of type L6, shock stage S2, and a weathering grade of W0. Following its analysis and classification, the meteorite was published under the official name Boumdeid (2011) in Meteoritical Bulletin, no. 100, MAPS 49(8), (2014). Gamma ray spectroscopy was conducted 84 days after the fall and the detection of short-lived radionuclides such as 56Co and 46Sc confirmed the recency of the event. Derived from the data of 60Co, 54Mn and 22Na the approximate preatmospheric radius of the meteorite body was 10–20cm. The report is also intended to serve as a case example for post-event data recovery and trajectory reconstruction in areas not covered by sky-camera networks and with limited scientific infrastructure.

3

Cosmogenic radionuclides in the Sołtmany (L6) meteorite

Laubenstein M., Giampaoli A., Janowski P., Mietelski J. W.

Meteorites

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2012

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Vol. 2, No. 1-2

45--51

EN

Cosmogenic radionuclides were measured in two specimens of the Sołtmany chondrite (L6) that fell on April 30, 2011. The first fragment (154.9 g) was measured 12 days after the fall and the second piece (120 g), 53 days after the fall. Both fragments were measured by means of non-destructive gamma ray spectroscopy. The first specimen was examined with an ultra-low background high purity germanium (HPGe) detector in a deep underground laboratory. A standard low-background HPGe detector was used to examine the second fragment in a ground level laboratory. Twelve cosmogenic nuclides were detected in the activity range of 0.030 m・Bq g–1 until 1.5 m・Bq g–1 Their activities place constraints on the exposure history of the meteorite and reflect the effect of solar modulation of galactic cosmic rays during the solar maximum. On the activities of expected radionuclides 60 Co (< 0.0075 m・Bq g–1) and 44 Ti (< 0.023 m・Bq g–1) only upper limits could be given. Sołtmany is part of a group of only 14 meteorites where 52 Mn (5.591 d half life) could be determined.

4

Cosmogenic 22Na and 7Be in ground level air

Grabowska S., Mietelski J.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

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2004

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nr 1

81-82