Sample preparation laboratory for in situ produced cosmogenic nuclides

Head of laboratory

The setup of a sample preparation laboratory for in situ produced cosmogenic nuclides in our Institute begun in 2013. Since 2016, the laboratory has been prepared for processing quartz-containing sediment- and rock-samples for the Accelerator Mass Spectrometry (AMS) measurement of their in situ cosmogenic 10Be and 26Al concentrations.

Terrestrial in situ produced cosmogenic nuclides – a geochronological tool for Quaternary geology and geomorphology

Terrestrial in situ produced Cosmogenic Nuclides (TCN) are suitable for the determination of the exposure age, burial age and denudation rate of rock surfaces, sediments and landforms. The method is applicable in the time range of 102 to 106 years and at variable lithologies. This time range covers the entire Quaternary and Pliocene hence it has occupied a significant role among the tools of Quaternary geochronology.

Most important radioactive TCN in geological and geomorphological research are 10Be (t1/2: 1.387 Ma), 26Al (t1/2: 705 ka), 36Cl (t1/2: 301 ka) and 14C (t1/2: 5700 a). Two stable noble gas nuclides are also important, the 3He and the 21Ne. Radioactive nuclides reach their secular equilibrium after 3-4 half-lives, which defines the applicability range of the method.

See more about the method in: Gosse and Phillips (2001); Dunai (2010); Granger et al. (2013) and references therein.

Exposure age determination

Exposure age of a rock is the time elapsed since it has been exposed to cosmic irradiation. The measured TCN concentration is representative of the exposure age of the studied landform (1) if the formation of the landform was instantaneous and (2) if no surface denudation or (3) sediment accumulation has occurred since its formation. Glacial landforms, fluvial terraces and lava flows are among the most frequent targets of exposure age determination.

Determination of denudation rates

In case of steady erosion TCN concentration within the rock is approaching a secular equilibrium. The faster is the denudation the lower is the equilibrium level. Accordingly, on a surface of long term steady erosion TCN concentrations are suitable for the determination of the surface denudation rate. The method is suitable for the quantification of surface denudation rates (on uncovered or soil mantled surfaces) and for the determination of average erosion rates of entire drainage basins.

Burial age determination

In contrast with exposure age and denudation rate determinations, burial age dating is based on the radioactive decay of cosmogenic nuclides. Those rocks and sediments are suitable for burial dating which once were exposed to cosmic irradiation, but have been buried since then. The time of burial (shielding from cosmic rays) can be determined using cosmogenic nuclide-pairs with different half-lives. Typical example is the burial dating of sediment trapped in caves using the 26Al/10Be nuclide-pair.

References

  • Dunai, T.J. 2010. Cosmogenic Nuclides. Principles, Concepts and Applications in the Earth Surface Sciences. Cambridge Univ Press, New York, p. 187.
  • Gosse, J.C. and Phillips F.M. 2001. Terrestrial in situ cosmogenic nuclides: theory and application. Quaternary Science Reviews, 20. pp. 1475-1560.
  • Granger, D.E., Lifton, N.A., Willenbring, J. 2013. A cosmic trip: 25 years of cosmogenic nuclides in geology. GSA Bulletin, 125, 1379-1402.
  • Ruszkiczay-Rüdiger, Zs. 2004. Kitettségi kor és eróziós ráta meghatározásának módszere helyben keletkező kozmogén izotópokkal. Földt. Közl. 134/2. pp. 257-279.

Presentation of the sample preparation laboratory

The laboratory is ready to process quartz-containing samples for the AMS measurement of their in situ cosmogenic 10Be and 26Al concentrations.

10Be is the by far the most commonly measured cosmogenic nuclide. Main reasons for its popularity in geological applications: (1) the abundance of the target mineral, quartz, (2) low natural 9Be concentrations, (3) standardized chemistry, (4) good AMS precision, (5) relatively simple production depth profile.

Cosmogenic 26Al is usually used in pair with 10Be. These nuclides can be measured on the same aliquot after a standardized chemistry process, and their different half-lives, and relatively well studied 26Al/10Be production ratio makes them well suited to solve a variety of complex exposure and burial histories and to determine surface denudation rates. The sample preparation follows the procedures described by Ruszkiczay-Rüdiger et al. (2021).

Sample preparation for the measurement of cosmogenic in situ produced 10Be and 26Al concentrations of quartz-containing rock samples

Physical treatment of the samples

From July 2017 crushing of rock samples occurs with a new Fritsch jaw crusher (Pulverisette 1, Model 2, Premium Line). (Earlier crushing occurred by a Retsch BB200 jaw crusher at the Central research and Instrument Centre of the Eötvös University, Budapest).

Sieving occurs using a Retsch AS200 Vibratory Sieve Shaker in the Laboratory for Sediment and Soil Analysis of the Research Centre for Astronomy and Earth Sciences, Geographical Institute.

After getting rid of the carbonate and organic matter content of the crushed and sieved samples, a shape separator is used to separate platy minerals, like mica, from minerals of more isotropic shape. Then density separation is applied using heavy liquid (LST fastfloat) to separate quartz from heavier and lighter minerals.

Chemical treatment of the samples

Chemical sample processing follows the procedures described by Brown et al. (1991) és Merchel and Herpers (1999). The quartz separates are chemically etched in (HCl-H2SiF6) and pure quartz is dissolved in in the presence of 9Be carrier and evaporated. After substitution of HF by hydrochloric acid (HCl). 27Al carrier is added to the samples if necessary and ion exchange columns (Dowex 1x8 and 50Wx8) and pH selective precipitation are used to extract 10Be and 26Al. Hydroxides are ignited at 900°C to reach the purified BeO and Al2O3. The oxides are mixed with Nb and Ag powders, and pressed into cathodes, which will be the targets of the AMS measurements.

Measurements

27Al concentrations (in case of samples for 26Al determination) are measured at external laboratories:

  1. at the Institute of Nuclear Research, Hertelendy Laboratory of Environmental Studies (Debrecen, Hungary) using an Agilent MP-AE S 4100 facility;
  2. at the CEREGE (Aix en Provence, France) by ICP-OES; ICAP 6500 from Thermofisher;
  3. at BOKU (Vienna, Austria) using a Perkin Elmer Optima 8300 ICP-OES instrument.

AMS measurements of isotope ratios of BeO and Al2O3 samples are performed at ASTER, the French National Facility, CEREGE, (Aix en Provence, France; Arnold et al., 2010) or at VERA, the Vienna Environmental Research Accelerator, Faculty of Physics, University of Vienna, (Vienna, Austria; Steier et al., 2019) in the framework of scientific cooperation. The measurements at ASTER were supported by the INSU/CNRS, the French Ministry of Research and Higher Education, IRD and CEA. Measurements performed at VERA were supported by the RADIATE Transnational Access (19001687-ST, 19001688-ST, 20002322-ST, 22002703-ST).

References

  • Arnold, M., Merchel, S., Bourlès, D.L., Braucher, R., Benedetti, L., Finkel, R.C., Aumaître, G., Gottdang, A., Klein, M., 2010. The French accelerator mass spectrometry facility ASTER: improved performance and developments. Nuclear Instruments and Methods in Physics Research B 268, 1954–1959.
  • Brown, E.T., Edmond, J.M., Raisbeck, G.M., Yiou, F., Kurz, M.D., Brook, E.J. 1991. Examination of surface exposure ages of Antarctic moraines using in situ produced 10Be and 26Al, Geochim. Cosmochim. Acta 55:2269-2283
  • Merchel, S., Herpers, U., 1999. An Update on Radiochemical Separation Techniques for the Determination of Long-Lived Radionuclides via Accelerator Mass Spectrometry, Radiochimica Acta 84, 215-219.3,
  • Ruszkiczay-Rüdiger, Zs., Neuhuber, S., Braucher, R., Lachner, J., Steier, P., Wieser, A., Braun, M., ASTER Team 2021. Comparison and performance of two cosmogenic nuclide sample preparation procedures of in situ produced 10Be and 26Al. Journal of Radioanalytical and Nuclear Chemistry, 329(3), 1523-1536.
  • Steier, P., Martschini, M., Buchriegler, J., Feige, J., Lachner, J., Merchel, S., Milchmayr, L., Priller, A., Rugel, G., Schmidt, E., Wallner, A., Wild, E.M., Golser, R., 2019. Comparison of methods for the detection of 10Be with AMS and a new approach based on a silicon nitride foil stack. International Journal of Mass Spectrometry, 444, 116175

Applications

  1. Determination of the exposure age and denudation rate of wind abraded rock surfaces using 10Be depth profiles
    • Ruszkiczay-Rüdiger, Zs., Braucher, R., Csillag, G., Fodor, L., Dunai, T.J., Bada, G., Bourlés, D., Müller, P. 2011. Dating pleistocene aeolian landforms in Hungary, Central Europe, using in situ produced cosmogenic . Quaternary Geochronology, 6, pp. 515-529.
    • Sebe, K., Csillag, G., Ruszkiczay-Rüdiger, Zs. , Fodor, L., Thamó-Bozsó, E., Müller, P., Braucher, R. 2011. Wind erosion under cold climate: A Pleistocene periglacial mega-yardang system in Central Europe (Western Pannonian Basin, Hungary). Geomorphology, 134, pp. 470-482.
  2. Determination of the exposure age and denudation rate of terraces of the Danube river in the central Pannonian Basin using 10Be depth profiles and 26Al/10Be burial durations, in combination with luminescence dating. The chronological data are used for the determination of the uplift rate of the area.
    • Ruszkiczay-Rüdiger, Zs., Braucher, R., Novothny, Á., Csillag, G., Fodor, L., Molnár, G., Madarász, B., & ASTER Team 2016a. Tectonic and climatic forcing on terrace formation: coupling in situ produced depth profiles and luminescence approach, Danube River, Hungary, Central Europe. Quaternary Science Reviews 131, 127-147.
    • Ruszkiczay-Rüdiger, Zs., Csillag, G., Fodor, L., Braucher, R., Novothny, Á., Thamó-Bozsó, E., Virág, A., Pazonyi, P., Timár, G., ASTER Team 2018. Integration of new and revised chronological data to constrain the terrace evolution of the Danube River (Gerecse Hills, Pannonian Basin). Quaternary Geochronology 48, 148-170.
    • Ruszkiczay-Rüdiger, Z., Balázs, A., Csillag, G., Drijkoningen, G., & Fodor, L. 2020a. Uplift of the Transdanubian Range, Pannonian Basin: How fast and why? Global and Planetary Change, 103263. 1-17.
  3. Burial age determination of Danube terraces in the Vienna Basin and inter-laboratory comparison of different sample processing protocols.
    • Ruszkiczay-Rüdiger, Zs., Neuhuber, S., Decker, K., Braucher, R., Fiebig, M., Braun, M., Lachner, J., ASTER Team 2017. Isochron burial dating of the Haslau terrace of the Danube (Vienna Basin) and interlaboratory comparison of sample preparation in Vienna and Budapest. Geophysical Research Abstracts 18, EGU2017-6239
    • Ruszkiczay-Rüdiger, Zs., Neuhuber, S., Braucher, R., Lachner, J., Steier, P., Wieser, A., Braun, M., ASTER Team 2021. Comparison and performance of two cosmogenic nuclide sample preparation procedures of in situ produced 10Be and 26Al. Journal of Radioanalytical and Nuclear Chemistry, 329(3), 1523-1536.
  4. 10Be exposure age determination of glacial landforms in the Southern Carpathians and in the Central Balkan Peninsula
    • Ruszkiczay-Rüdiger, Zs., Kern, Z., Urdea, P., Braucher, R., Madarász, B., Schimmelpfennig, I., ASTER Team 2016b. Revised deglaciation history of the Pietrele- Stânişoara glacial complex, Retezat Mts, Southern Carpathians, Romania. Quaternary International, 415, 216-229. doi:10.1016/j.quaint.2015.10.085
    • Ruszkiczay-Rüdiger, Zs., Kern, Z., Temovski, M., Madarász, B., Milevski, I., Braucher, R., ASTER Team. 2020b. Last deglaciation in the central Balkan Peninsula: geochronological evidence from the Jablanica Mt. (North Macedonia). Geomorphology, 351. 106985. doi: 10.1016/j.geomorph.2019.106985. 1-13.
    • Ruszkiczay-Rüdiger, Zs., Kern, Z., Urdea, P., Madarász, B., Braucher, R., ASTER Team 2021. Limited glacial erosion during the last glaciation in mid-latitude cirques (Retezat Mts, Southern Carpathians, Romania). Geomorphology, 107719.
    • Ruszkiczay-Rüdiger, Zs., Temovski, M., Kern, Z., Madarász, B., Milevski, I., Lachner, J., & Steier, P. 2022. Late Pleistocene glacial advances, equilibrium-line altitude changes and paleoclimate in the Jakupica Mts (North Macedonia). CATENA, 216, 106383.

Ongoing project: Geochronology of glacial landforms and cave sediments in Macedonia and implications for Quaternary landscape evolution in the Central Balkan Peninsula (GeCosMa) with the support of the NKFIH FK 124807 (2017-2022) project.

Support

The setup and launching of the laboratory was enabled by the National Scientific Found of Hungary (OTKA 83610). Further developments were supported by the “Lendület” program of the Hungarian Academy of Sciences (LP2012-27/2012) and by the infrastructure acquired through the proposals of the Hungarian Academy of Sciences (MTA INFRA-2017/103 and -2018/065). The research carried out in the lab was/is supported by National Research, Development and Innovation Office, NKFIH 124807, and the OMAA 90öu17 and 98öu17 projects.

Contact

  • Zsófia Ruszkiczay-Rüdiger
  • Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, Eötvös Loránd Research Network
  • 1112, Budapest, Budaörsi út 45.
  • ruszkiczay-rudiger.zsofia at csfk.hun-ren.hu