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  • 51. Buraglio, N
    et al.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    I-129 in fresh water lakes of Chernobyl fallout1999Conference paper (Refereed)
  • 52. Buraglio, N
    et al.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    I-129 in preciptation and runoff in central Sweden and north Italy1999In: The 2nd International Congress of Limnogeology, Brest, France, 1999Conference paper (Refereed)
  • 53.
    Chen, P.
    et al.
    Hohai Univ, State Key Lab Hydrol Water Resources & Hydraul, Nanjing 210098, Peoples R China.;Hohai Univ, Coll Hydrol & Water Resources, Nanjing 210098, Peoples R China..
    Yu, Z. B.
    Hohai Univ, State Key Lab Hydrol Water Resources & Hydraul, Nanjing 210098, Peoples R China.;Hohai Univ, Coll Hydrol & Water Resources, Nanjing 210098, Peoples R China..
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. United Arab Emirates Univ, Dept Geol, Al Ain, U Arab Emirates..
    Yi, P.
    Hohai Univ, State Key Lab Hydrol Water Resources & Hydraul, Nanjing 210098, Peoples R China.;Hohai Univ, Coll Hydrol & Water Resources, Nanjing 210098, Peoples R China..
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Mugwaneza, Vincent de Paul
    Hohai Univ, State Key Lab Hydrol Water Resources & Hydraul, Nanjing 210098, Peoples R China.;Hohai Univ, Coll Hydrol & Water Resources, Nanjing 210098, Peoples R China..
    Comparison of measurement and modeling results of the global Be-10 flux in topsoil2017In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 311, no 3, p. 2039-2045Article in journal (Refereed)
    Abstract [en]

    Soils are among the major terrestrial reservoirs of atmospheric Be-10 isotope and provide information of landscape evolution history. Despite this importance, there is no overview of the global soil Be-10 fluxes in topsoil that is linked with atmospheric flux models. A comparison between measured (in topsoil) and atmospherically modeled Be-10 fluxes is presented here. The data show relatively good agreement in the latitudinal trends. This feature demonstrates the potential to use the modeling data in estimating soil development/erosion rates in large scale basins where extensive Be-10 measurements can be limited.

  • 54.
    Czymzik, Markus
    et al.
    Lund Univ, Dept Geol, Quaternary Sci, S-22362 Lund, Sweden..
    Adolphi, Florian
    Lund Univ, Dept Geol, Quaternary Sci, S-22362 Lund, Sweden..
    Muscheler, Raimund
    Lund Univ, Dept Geol, Quaternary Sci, S-22362 Lund, Sweden..
    Mekhaldi, Florian
    Lund Univ, Dept Geol, Quaternary Sci, S-22362 Lund, Sweden..
    Martin-Puertas, Celia
    GEZ German Res Ctr Geosci, Sect Climate Dynam & Landscape Evolut 5 2, D-14473 Potsdam, Germany..
    Aldahan, Ala
    United Arab Emirates Univ, Dept Geol, Al Ain 15551, U Arab Emirates..
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Brauer, Achim
    GEZ German Res Ctr Geosci, Sect Climate Dynam & Landscape Evolut 5 2, D-14473 Potsdam, Germany..
    A varved lake sediment record of the Be-10 solar activity proxy for the Lateglacial-Holocene transition2016In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 153, p. 31-39Article in journal (Refereed)
    Abstract [en]

    Solar modulated variations in cosmogenic radionuclide production provide both information on past changes in the activity of the Sun and a global synchronization tool. However, to date the use of cosmogenic radionuclides for these applications is almost exclusively based on Be-10 records from ice cores and C-14 time-series from tree rings, all including archive-specific limitations. We present the first Be-10 record from annually laminated (varved) lake sediments for the Lateglacial-Holocene transition from Meerfelder Maar. We quantify environmental influences on the catchment and, consequently, Be-10 deposition using a new approach based on regression analyses between our Be-10 record and environmental proxy time-series from the same archive. Our analyses suggest that environmental influences contribute to up to 37% of the variability in our Be-10 record, but cannot be the main explanation for major Be-10 excursions. Corrected for these environmental influences, our Be-10 record is interpreted to dominantly reflect changes in solar modulated cosmogenic radionuclide production. The preservation of a solar production signal in Be-10 from varved lake sediments highlights the largely unexplored potential of these archives for solar activity reconstruction, as global synchronization tool and, thus, for more robust paleoclimate studies.

  • 55. Dahl-Jensen, D.
    et al.
    Albert, M. R.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Azuma, N.
    Balslev-Clausen, D.
    Baumgartner, M.
    Berggren, Ann-Marie
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bigler, M.
    Binder, T.
    Blunier, T.
    Bourgeois, J. C.
    Brook, E. J.
    Buchardt, S. L.
    Buizert, C.
    Capron, E.
    Chappellaz, J.
    Chung, J.
    Clausen, H. B.
    Cvijanovic, I.
    Davies, S. M.
    Ditlevsen, P.
    Eicher, O.
    Fischer, H.
    Fisher, D. A.
    Fleet, L. G.
    Gfeller, G.
    Gkinis, V.
    Gogineni, S.
    Goto-Azuma, K.
    Grinsted, A.
    Gudlaugsdottir, H.
    Guillevic, M.
    Hansen, S. B.
    Hansson, M.
    Hirabayashi, M.
    Hong, S.
    Hur, S. D.
    Huybrechts, P.
    Hvidberg, C. S.
    Iizuka, Y.
    Jenk, T.
    Johnsen, S. J.
    Jones, T. R.
    Jouzel, J.
    Karlsson, N. B.
    Kawamura, K.
    Keegan, K.
    Kettner, E.
    Kipfstuhl, S.
    Kjaer, H. A.
    Koutnik, M.
    Kuramoto, T.
    Koehler, P.
    Laepple, T.
    Landais, A.
    Langen, P. L.
    Larsen, L. B.
    Leuenberger, D.
    Leuenberger, M.
    Leuschen, C.
    Li, J.
    Lipenkov, V.
    Martinerie, P.
    Maselli, O. J.
    Masson-Delmotte, V.
    McConnell, J. R.
    Miller, H.
    Mini, O.
    Miyamoto, A.
    Montagnat-Rentier, M.
    Mulvaney, R.
    Muscheler, R.
    Orsi, A. J.
    Paden, J.
    Panton, C.
    Pattyn, F.
    Petit, J. -R
    Pol, K.
    Popp, T.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Prie, F.
    Prokopiou, M.
    Quiquet, A.
    Rasmussen, S. O.
    Raynaud, D.
    Ren, J.
    Reutenauer, C.
    Ritz, C.
    Rockmann, T.
    Rosen, J. L.
    Rubino, M.
    Rybak, O.
    Samyn, D.
    Sapart, C. J.
    Schilt, A.
    Schmidt, A. M. Z.
    Schwander, J.
    Schuepbach, S.
    Seierstad, I.
    Severinghaus, J. P.
    Sheldon, S.
    Simonsen, S. B.
    Sjolte, J.
    Solgaard, A. M.
    Sowers, T.
    Sperlich, P.
    Steen-Larsen, H. C.
    Steffen, K.
    Steffensen, J. P.
    Steinhage, D.
    Stocker, T. F.
    Stowasser, C.
    Sturevik, A. S.
    Sturges, W. T.
    Sveinbjornsdottir, A.
    Svensson, A.
    Tison, J. -L
    Uetake, J.
    Vallelonga, P.
    van de Wal, R. S. W.
    van der Wel, G.
    Vaughn, B. H.
    Vinther, B.
    Waddington, E.
    Wegner, A.
    Weikusat, I.
    White, J. W. C.
    Wilhelms, F.
    Winstrup, M.
    Witrant, E.
    Wolff, E. W.
    Xiao, C.
    Zheng, J.
    Eemian interglacial reconstructed from a Greenland folded ice core2013In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 493, no 7433, p. 489-494Article in journal (Refereed)
    Abstract [en]

    Efforts to extract a Greenland ice core with a complete record of the Eemian interglacial (130,000 to 115,000 years ago) have until now been unsuccessful. The response of the Greenland ice sheet to the warmer-than-present climate of the Eemian has thus remained unclear. Here we present the new North Greenland Eemian Ice Drilling ('NEEM') ice core and show only a modest ice-sheet response to the strong warming in the early Eemian. We reconstructed the Eemian record from folded ice using globally homogeneous parameters known from dated Greenland and Antarctic ice-core records. On the basis of water stable isotopes, NEEM surface temperatures after the onset of the Eemian (126,000 years ago) peaked at 8 +/- 4 degrees Celsius above the mean of the past millennium, followed by a gradual cooling that was probably driven by the decreasing summer insolation. Between 128,000 and 122,000 years ago, the thickness of the northwest Greenland ice sheet decreased by 400 +/- 250 metres, reaching surface elevations 122,000 years ago of 130 +/- 300 metres lower than the present. Extensive surface melt occurred at the NEEM site during the Eemian, a phenomenon witnessed when melt layers formed again at NEEM during the exceptional heat of July 2012. With additional warming, surface melt might become more common in the future.

  • 56.
    Englund, Edvard
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Alfimov, V.
    A routine preparation method for AMS measurement of 129I in solid material2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, p. 365-369Article in journal (Refereed)
    Abstract [en]

    Here we present results of an 129I extraction procedure applied to solid matrices (soils and organic matters), which is based on combustion of samples in an oxygen atmosphere. Stepwise heating and continuous warming of the whole system were critical points in order to achieve relatively satisfactory yields of iodine from samples ranging up to 1.5 g. Repeated combustions of blanks show both stable background levels and no significant memory effects. We have processed a series of different types of sample materials including standard soil, maple leaves and surface soil from Uppsala in Central Sweden. The results show analytical reproducibility and agreement with reported values.

  • 57.
    Englund, Edvard
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Alfimov, Vasily
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. ELD.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. jonfysik.
    A routine preparation method for AMS measurement of I-129 in solid materials2005In: 10th International conference on accelerator mass spectrometry, Berkeley, 2005, p. 75-Conference paper (Other (popular scientific, debate etc.))
  • 58. Gallagher, Donal
    et al.
    McGee, Eddi
    Mitchell, Peter
    Alfimov, Vasely
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. ELD.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences, Ion Physics. Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Retrospective Serach for evidence of the 1957 Windscale fire in NE Ireland using 129I and other long-lived nuclides2005In: Environmental Science and Technology, Vol. 39, p. 2927-2935Article in journal (Refereed)
  • 59. Grönvold, K
    et al.
    Oskarsson, O
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    Cosmogenic 10Be and the origin of Icelandic acid rocks2000In: EOS Transactions American Geophysical Union, 81, AGU Fall Meeting abstracts, 2000, p. F1357-Conference paper (Refereed)
  • 60. Hakansson, Lena
    et al.
    Briner, Jason P.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    (10)Be data from meltwater channels suggest that Jameson Land, east Greenland, was ice-covered during the last glacial maximum2011In: Quaternary Research, ISSN 0033-5894, E-ISSN 1096-0287, Vol. 76, no 3, p. 452-459Article in journal (Refereed)
    Abstract [en]

    Along the northeast Greenland continental margin, bedrock on interfjord plateaus is highly weathered, whereas rock surfaces in fjord troughs are characterized by glacial scour. Based on the intense bedrock weathering and lack of glacial deposits from the last glaciation, interfjord plateaus have long been thought to be ice-free throughout the last glacial maximum (LGM). In recent years there is growing evidence from shelf and fjord settings that the northeast Greenland continental margin was more extensively glaciated during the LGM than previously thought. However, little is still known from interfjord settings. We present cosmogenic (10)Be data from meltwater channels and weathered sandstone outcrops on Jameson Land, an interfjord highland north of Scoresby Sund. The mean exposure age of samples from channel beds (n = 3) constrains on the onset of deglaciation on interior Jameson Land to 18.5 +/- 1.3-21.4 +/- 1.9 ka (for erosion conditions of 0-10 mm/ka, respectively). This finding adds to growing evidence that the northeast Greenland continental margin was more heavily glaciated during the LGM than previously thought.

  • 61. Hansen, Violeta
    et al.
    Roos, Per
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, Xiaolin
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Partition of iodine ((129)I and (127)I) isotopes in soils and marine sediments2011In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 102, no 12, p. 1096-1104Article in journal (Refereed)
    Abstract [en]

    Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope (129)I is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter. Due to its long half-life (15.7 million years), (129)I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of (129)I and (127)I chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify (129)I in humic and fulvic acid and humin. The results show that 30-56% of the total (127)I and 42-60% of the total (129)I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, (127)I and (129)I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 (129)I was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions.

  • 62. Hansen, Violeta
    et al.
    Yi, Peng
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, Xiaolin
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Roos, Per
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Iodide and iodate ((129)I and (127)I) in surface water of the Baltic Sea, Kattegat and Skagerrak2011In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 412, p. 296-303Article in journal (Refereed)
    Abstract [en]

    Despite the common incorporation of iodine in the biological cycle and occurrence of huge contamination of the radioactive isotope (129)I in the Baltic Proper, Skagerrak and Kattegat, there is no data on chemical speciation of iodine in these waters. We here present first time data on iodine isotopes (129)I and (127)I species as iodide and iodate in surface seawater samples collected from 16 locations in August 2006 and 19 locations in April 2007 in the Baltic Proper, Skagerrak and Kattegat. After extensive separation methods, the isotopes concentrations were determined using accelerator mass spectrometry (AMS) technique for the (129)I and inductively coupled plasma mass spectroscopy (ICP-MS) for (127)I. High concentrations of both isotopes species were found in the Skagerrak-Kattegat basins, whereas the values in the Baltic Proper are low for both species. The ratios of (129)I(-)/(129)IO(3)(-) and (127)I-/(127)IO(3)(-) significantly increase from south to central Baltic Sea, and iodide (both isotopes) appears as the predominant inorganic iodine species along the Baltic Sea. The results show insignificant change in (129)I and (127)I speciation and suggest that reduction of iodate and oxidation of iodide in Skagerrak and Kattegat may be a slow process. Additionally, the positive correlation between salinity and iodide and iodate (both isotopes) may reflect effective control of Skagerrak water mass on iodine distribution in surface water of the Baltic Sea.

  • 63.
    Haussmann, Natalie
    et al.
    Department of Conservation Ecology and Entomology, Stellenbosch University, South Africa.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Boelhouwers, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    10Be application to soil development on Marion Island, southern Indian Ocean2010In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 268, no 7-8, p. 1058-1061Article in journal (Refereed)
    Abstract [en]

    Marion Island, located in the southern Indian Ocean, constitutes the summit of an active shield volcano. It is a small terrestrial environment where glacially abraded bedrock became exposed c × 10 kyr ago. These conditions provide an interesting possibility for the assessment of 10Be accumulation rates and their application to soil erosion studies on the island. 10Be concentrations were measured in precipitation, soil profiles and an Azorella selago cushion plant. The data reveal a 10Be precipitation flux several times higher than model prediction. Estimation of the 10Be accumulation based on the soil inventory suggests a span between 2000 and 7000 yr. This time span is not in accordance with the accepted notion that the island was covered with ice about 10,000 yr ago and suggests either removal of 10Be from the soil profile, an overestimated Holocene 10Be-flux or a delayed soil development history. Our results provide new data on 10Be concentrations from the sub-Antarctic islands and contribute towards enlarging the southern-hemisphere 10Be database.

  • 64.
    He, Peng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Hou, Xiaolin
    Temporal variation of iodine isotopes in the North Sea2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 3, p. 1419-1425Article in journal (Refereed)
  • 65.
    He, Peng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, Xiaolin
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Goran
    Radioactive I-129 in surface water of the Celtic Sea2014In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 299, no 1, p. 249-253Article in journal (Refereed)
    Abstract [en]

    Relatively large amounts of radioactive iodine 129I (T 1/2  = 15.7 Ma) have been documented in seawater such as the English Channel, the Irish Sea and the North Sea. Data on the concentration of the iodine isotopes in waters of the Celtic Sea are missing. Aiming to provide first 129I data in the Celtic Sea and compare them with levels in the other close-by seawater bodies, surface seawater samples were analyzed for the determination of 127I and 129I concentrations. The results revealed a high level of 129I in these waters and suggest strong influence by liquid discharges from La Hague and Sellafield reprocessing facilities. 127I concentrations are rather constant while the 129I/127I ratio reaches up to 2.8 × 10−8 (ranging from 10−10 to 10−8), which is 2–4 orders of magnitude higher than pre-nuclear era natural level. Transport of 129I to the Celtic Sea is difficult to depict accurately since available data are sparse. Most likely, however, that discharges originated from La Hague may have more influence on the Celtic Sea 129I concentrations than the Sellafield. Comprehensive surface water and depth profiles 129I data will be needed in the future for assessment of environmental impact in the region.

  • 66.
    He, Peng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, Xiaolin
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Yi, Peng
    Iodine isotopes species fingerprinting environmental conditions in surface water along the northeastern Atlantic Ocean2013In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 3, p. 2685-Article in journal (Refereed)
    Abstract [en]

    Concentrations and species of iodine isotopes (I-127 and I-129) provide vital information about iodine geochemistry, environmental conditions and water masses exchange in oceans. Despite extensive investigations of anthropogenic I-129 in the Arctic Ocean and the Nordic Seas, concentrations of the isotope in the Atlantic Ocean are, however, still unknown. We here present first data on I-129 and I-127, and their species (iodide and iodate) in surface water transect along the northeastern Atlantic between 30 degrees and 50 degrees N. The results show iodate as the predominant species in the analyzed marine waters for both I-127 and I-129. Despite the rather constant ratios of I-127(-)/(IO3-)-I-127, the I-129(-)/(IO3-)-I-129 values reveal variations that apparently response to sources, environmental conditions and residence time. These findings provide a new tracer approach that will strongly enhance the application of anthropogenic I-129 in ocean environments and impact on climate at the ocean boundary layer.

  • 67. Hedfors, J
    et al.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. miljö-och landskapsdynamik.
    Kulan, A
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Clouds and 7Be:perusing connections between cosmic rays and climat2006In: Geophysical Research Letters, Vol. 111, p. D02208, doi:10.1029/2005JD005903-Article in journal (Refereed)
  • 68.
    Hou, Xiaolin
    et al.
    Rise National Laboratory, NUK-202, Technical University of Denmark.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Neilsen, Sven
    Rise National Laboratory, NUK-202, Technical University of Denmark.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Nies, Hartmut
    Bundesamt fuer Seeschiffahrt und Hydrographie.
    Hedfors, Jim
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Speciation of I-129 and I-127 in seawater and implications for sources and transport pathways in the North Sea2007In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 41, no 17, p. 5993-5999Article in journal (Refereed)
    Abstract [en]

    Surface seawater samples collected from the North Sea and English Channel were analyzed for total 129I and 127I, as well as for iodide and iodate. Relatively high 129I concentrations (2−3 × 1011 atoms/L) were observed in the northern part of the English Channel and in the southeastern North Sea. The atomic ratio of 129I/127I decreases from the eastern (1.0−1.9 × 10-6) to the western (4−6 × 10-8) parts of the North Sea and from the northeastern (1.5 × 10-6) to southwestern (1−5 × 10-8) parts of the English Channel. The ratios of iodide to iodate are 0.1−0.5 and 0.5−1.6 for 127I and 129I, respectively, in open seawaters, whereas these ratios range from 0.6 to 1.3 and 0.8 to 2.2, respectively, in coastal waters. The results suggest that (1) imprints of the La Hague facility dominates the 129I distribution in the surface water of the North Sea, (2) reduction of iodate to iodide is relatively fast during the transport to the European continental coast, (3) oxidation of newly produced 129I- to 129IO3- is insignificant during water exchange between the coastal area and open sea, (4) reduction of iodate and oxidation of iodide in the open sea seems to be a slow process.

  • 69. Håkansson, Lena
    et al.
    Alexanderson, H
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. miljö-och landskapsdynamik.
    Briner, J
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Using cosmogenic isotopes to reconcile two contrasting hypotheses for ice extent in East Greenland during the last glaciation2006Conference paper (Refereed)
  • 70. Håkansson, Lena
    et al.
    Briner, Jason
    Alexanderson, Helena
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    10Be ages from central east Greenland constrain the extent of the Greenland ice sheet during the Last Glacial Maximum2007In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 26, no 19-21, p. 2316-2321Article in journal (Refereed)
    Abstract [en]

    Traditional ice sheet reconstructions have suggested two distinctly different ice sheet regimes along the East Greenland continental margin during the Last Glacial Maximum (LGM): ice to the shelf break south of Scoresby Sund and ice extending no further than to the inner shelf at and north of Scoresby Sund. We report new 10Be ages from erratic boulders perched at 250 m a.s.l. on the Kap Brewster peninsula at the mouth of Scoresby Sund. The average 10Be ages, calculated with an assumed maximum erosion rate of 1 cm/ka and no erosion (respectively, 17.3±2.3 ka and 15.1±1.7 ka) overlap with a period of increased sediment input to the Scoresby Sund fan (19–15 ka). The results presented here suggest that ice reached at least 250 m a.s.l. at the mouth of Scoresby Sund during the LGM and add to a growing body of evidence indicating that LGM ice extended onto the outer shelf in northeast Greenland.

  • 71.
    Kekli, A
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics.
    Aldahan, A A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. ELD.
    Meili, M
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Buraglio, N
    Stepanauskas, R
    129I in Swedish rivers distrbution and sources2003In: The Science of Total Environment, no 309Article in journal (Refereed)
  • 72.
    Keogh, Sinead
    et al.
    School of Physics, University College Dublin.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Finegan, P.
    School of Physics, University College Dublin.
    Vintro, L
    School of Physics, University College Dublin.
    Mitchel, P
    School of Physics, University College Dublin.
    Trends in the spatial and temporal distribution of 129I and 99Tc in coastal waters surrounding Ireland using Fucus vesiculosus as a bio-indicator2007In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 95, no 1, p. 23-38Article in journal (Refereed)
    Abstract [en]

    Spatial and temporal trends in 129I and 99Tc concentrations around the Irish coastline have been evaluated using Fucus vesiculosus as a bio-indicator. 129I concentrations in a recent set of seawater samples have also been recorded and reveal an identical spatial pattern. Concentrations of 129I in Fucus from the northeast coast of Ireland proved to be at least two orders of magnitude higher than concentrations in Fucus from the west coast. The 129I content of Fucus increased significantly between 1985 and 2003, in line with increases in discharges of 129I from the Sellafield nuclear reprocessing plant. Similar trends were observed in the case of 99Tc. 129I/99Tc ratios in Irish seawater were deduced from the Fucus data, and compared to ratios in discharges from Sellafield and from the French reprocessing plant at Cap de la Hague. Levels of 129I and 99Tc in Fucus from the west coast were found to be enhanced with respect to levels in seaweeds from other regions in the Northern Hemisphere unaffected by discharges from nuclear installations such as those referred to.

  • 73. Kulan, A
    et al.
    Aldahan, Ala
    Uppsala University.
    Possnert, Göran
    Uppsala University.
    Vintersved, I
    Solar cycle activity recorded in cosmogenic isotope Be-72002In: IGBP-PAGES Swedish National Meeting, March 14-16, Stockholm, 2002Conference paper (Refereed)
  • 74.
    Kulan A., Vintersved I
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. ELD.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. Jonfysik.
    Solar cycle activity and atmospheric dynamics revealed by Be-72003In: Geophysical Research Abstr., 2003, p. 11267-Conference paper (Refereed)
  • 75. Lehto, Jukka
    et al.
    Raty, Tero
    Hou, Xiaolin
    Paatero, Jussi
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Flinkman, Juha
    Kankaanpaa, Harri
    Speciation of I-129 in sea, lake and rain waters2012In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 419, p. 60-67Article in journal (Refereed)
    Abstract [en]

    Concentrations of the very long-lived fission product I-129 and stable iodine (I-127) in the Baltic Sea and lake and rain waters from Finland, were measured as well as their occurrence as iodide (I-) and iodate (IO3-). The highest concentrations of both I-127 and I-129 occurred in sea water, on average 11.1 +/- 4.3 mu g/l and 3.9 +/- 4.1 x 10(-9) at/l. In rain and lake waters the concentration of I-129 was more or less identical and almost one order of magnitude lower than in sea water. Based on these observations, and data from the literature, it is assumed that the source of I-129 in lakes is precipitation and the major source in the Baltic Sea is the inflow of sea water from the North Sea through the Danish Straits. The concentration of I-129 in the Baltic Sea has increased by a factor of six during ten years from 1999. In all studied water types the main chemical form of both iodine isotopes was iodide; in sea and lake waters by 92-96% and in rain water by 75-88%. Compared to I-127 the fraction of iodide was slightly higher in case of I-129 in all waters.

  • 76. Martin-Puertas, Celia
    et al.
    Matthes, Katja
    Brauer, Achim
    Muscheler, Raimund
    Hansen, Felicitas
    Petrick, Christof
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    van Geel, Bas
    Regional atmospheric circulation shifts induced by a grand solar minimum2012In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 5, no 6, p. 397-401Article in journal (Refereed)
    Abstract [en]

    Large changes in solar ultraviolet radiation can indirectly affect climate(1) by inducing atmospheric changes. Specifically, it has been suggested that centennial-scale climate variability during the Holocene epoch was controlled by the Sun(2,3). However, the amplitude of solar forcing is small when compared with the climatic effects and, without reliable data sets, it is unclear which feedback mechanisms could have amplified the forcing. Here we analyse annually laminated sediments of Lake Meerfelder Maar, Germany, to derive variations in wind strength and the rate of Be-10 accumulation, a proxy for solar activity, from 3,300 to 2,000 years before present. We find a sharp increase in windiness and cosmogenic Be-10 deposition 2,759 +/- 39 varve years before present and a reduction in both entities 199 +/- 9 annual layers later. We infer that the atmospheric circulation reacted abruptly and in phase with the solar minimum. A shift in atmospheric circulation in response to changes in solar activity is broadly consistent with atmospheric circulation patterns in long-term climate model simulations, and in reanalysis data that assimilate observations from recent solar minima into a climate model. We conclude that changes in atmospheric circulation amplified the solar signal and caused abrupt climate change about 2,800 years ago, coincident with a grand solar minimum.

  • 77. Meili, M
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences.
    129I in Arctic freshwaters: local or global sources?2002Conference paper (Refereed)
  • 78.
    Meili, M
    et al.
    ION PHYSICS.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences.
    Iodine-129 in Swedish rivers and coastal waters: Impact and fate of recent European emissions? Step 1: a regional surve2002Report (Other scientific)
  • 79. Meili, M
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences.
    Possnert, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences.
    Origin and fate of 129I in the European hydrosphere2002Conference paper (Refereed)
  • 80. Meili, M
    et al.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Hou, X.L
    Oughton, D
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    I-129 in the Arctic: regional and global atmosphere-land-sea interaction2001In: First NARP Symposium, The Arctic and Thinner Icem May-10-11, Oulu, Finland, 2001Conference paper (Other (popular scientific, debate etc.))
  • 81. Meili, M
    et al.
    Buraglio, N
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Possnert, Göran
    Technology, Department of Materials Science. jonfysik.
    Kekli, A
    Origin and fate of 129I in Swedish lakes and soils2001In: Proceedings of the 8th Nordic Seminar on Raioecology., 25-28 Feb. 2001 Rovaniemi, Finland, 2001, p. 90-Conference paper (Refereed)
  • 82. Morad, S
    et al.
    Alaasm, I
    Ramseyer, K
    Marfil, R
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Diagenesis of carbonate cement in Permo-Triassic sandstones from the Iberian Range, Spain: evidence from chemical composition and stable isotopes1990In: Sedimentary Geology, Vol. 67, p. 281-295Article in journal (Refereed)
  • 83. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    A SEM study of diagenetic kaolinization and illitization of detrital feldspars in sandstones1987In: Clay Minerals, Vol. 22, p. 237-243Article in journal (Refereed)
  • 84. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Alteration of authigenic K-feldspar in sandstones1988In: Bull. Geol. Inst. Uppsala, Vol. 12, p. 103-108Article in journal (Refereed)
  • 85. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Alteration of detrital Fe-Ti oxides in sedimentary rocks1986In: Geological. Society of America Bull., Vol. 97, p. 567-578Article in journal (Refereed)
  • 86. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Diagenetic alteration of detrital biotite in Proterozoic rocks from Sweden1986In: Sedimentary Geology, Vol. 47, p. 96-107Article in journal (Refereed)
  • 87. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Diagenetic chloritization of feldspars in sandstones1987In: Sedimentary Geology, Vol. 51, p. 155-164Article in journal (Refereed)
  • 88. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Diagenetic replacement of feldspars by quartz in sandstones1987In: Jour. Sedimentary Petrology, Vol. 57, p. 488-493Article in journal (Refereed)
  • 89. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Diagenetic replacement of feldspars by titanium oxides in sandstones1987In: Sedimentary Geology, Vol. 51, p. 147-153Article in journal (Refereed)
  • 90. Morad, S
    et al.
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Discussion and comments on the paper: electron-optical studies of phyllosilicates intergrowths in sedimentary and metamorphic rocks1986In: Mineralogical Magazine, Vol. 50, p. 340-343Article in journal (Refereed)
  • 91. Morad, S
    et al.
    Fillipides, A
    Aldahan, A
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. ELD.
    Ounchanum, P
    Stellerite and Sr-containing stilbite in granitic rocks from the Siljan Ring structure central Sweden1989In: Bull. Geol. Inst. Uppsala, Vol. 12, p. 143-149Article in journal (Refereed)
  • 92. Murad, A.
    et al.
    Alshamsi, D.
    Hou, X. L.
    Al Shidi, F.
    Al Kendi, R.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Radioactivity in groundwater along the borders of Oman and UAE2014In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 299, no 3, p. 1653-1660Article in journal (Refereed)
    Abstract [en]

    Characterizing the quality and radioactivity of groundwater is vital as it represents valuable resource in arid regions. Here we present radioactivity level in groundwater collected from wells in a region along the border between Sultanate of Oman and United Arab Emirates (UAE). The aquifers are alluvium deposits (silt, sand and gravel) and the measured groundwater radioactivity (including Th-232, U-238, U-235, Ra-226, Rn-222, gross-alpha and gross-beta) indicates values below the WHO permissible limits for drinking water. The results also show large difference in radioactivity fingerprints, in particular for Ra-226 and Rn-222 within the investigated aquifers. The data further indicate lower radioactivity in groundwater of the alluviums compared to the carbonate aquifers in the region. This feature makes the alluvium aquifers valuable reservoirs that should be carefully exploited as a source of groundwater. As this is the first investigation on the radioactivity of groundwater in alluvial aquifers in the region, it suggests that other alluvial deposits, particularly those inland and far from the marine water intrusion or seepage from carbonate rocks would have low radioactivity fingerprints.

  • 93. Murad, A.
    et al.
    Zhou, X. D.
    Yi, P.
    Alshamsi, D.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hou, X. L.
    Yu, Z. B.
    Natural radioactivity in groundwater from the south-eastern Arabian Peninsula and environmental implications2014In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 186, no 10, p. 6157-6167Article in journal (Refereed)
    Abstract [en]

    Groundwater is the most valuable resource in arid regions, and recognizing radiological criteria among other water quality parameters is essential for sustainable use. In the investigation presented here, gross-alpha and gross-beta were measured in groundwater samples collected in the south-eastern Arabian Peninsula, 67 wells in Unite Arab Emirates (UAE), as well as two wells and one spring in Oman. The results show a wide gross-alpha and gross-beta activities range in the groundwater samples that vary at 0.01 similar to 19.5 Bq/l and 0.13 similar to 6.6 Bq/l, respectively. The data show gross-beta and gross-alpha values below the WHO permissible limits for drinking water in the majority of the investigated samples except those in region 4 (Jabel Hafit and surroundings). No correlation between groundwater pH and the gross-alpha and gross-beta, while high temperatures probably enhance leaching of radionuclides from the aquifer body and thereby increase the radioactivity in the groundwater. This conclusion is also supported by the positive correlation between radioactivity and amount of total dissolved solid. Particular water purification technology and environmental impact assessments are essential for sustainable and secure use of the groundwater in regions that show radioactivity values far above the WHO permissible limit for drinking water.

  • 94.
    Muscheler, R
    et al.
    GeoBiosphere Science Centre, Quaternary Sciences, Lund University.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Berggren, Ann-Marie
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Svensson, A
    Niels Bohr Institute, Ice and Climate Research, University of Copenhagen, Denmark.
    Johnsen, S
    Niels Bohr Institute, Ice and Climate Research, University of Copenhagen.
    Björck, S
    GeoBiosphere Science Centre, Quaternary Sciences, Lund University.
    Beer, J
    Swiss Federal Institute of Aquatic Science and Technology, Switzerland.
    The cosmic ray clock during the Younger Dryas cold period clues about climate forcing and the timing of climate change: clues about climate forcing and the timing of climate change2009Conference paper (Refereed)
    Abstract [en]

    The last cold spell of the last deglaciation, the Younger Dryas period, serves as the prime example for rapid climate change induced by ocean circulation changes. However, the detailed processes behind this cold event are far from being satisfactorily understood. Although, the oceanic involvement in this climate deterioration is not disputed, there are various speculations about mechanisms that could have triggered and terminated it. Here we present 10Be data from the GRIP ice core around the transition from the Bölling/Alleröd warm period into the Younger Dryas cold period. The data provide a high-resolution cosmic ray signal that can be used to synchronize different radionuclide records and the connected climate reconstructions. This approach can lead to robust results about synchronous and non-synchronous climate changes at different locations, insights into the possible processes behind the changes and also the prospect of an improved 14C calibration beyond the Holocene period.

  • 95. Nath, Bejugam Nagender
    et al.
    Sijinkumar, Adukkam V.
    Borole, Dnyandev V.
    Gupta, Shyam M.
    Mergulhao, Lina P.
    Mascarenhas-Pereira, Maria B. L.
    Ramaswamy, Venkitasubramani
    Guptha, Medimi V. S.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Khadge, Nandkumar H.
    Sharma, Rahul
    Record of carbonate preservation and the Mid-Brunhes climatic shift from a seamount top with low sedimentation rates in the Central Indian Basin2013In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 42, no 3, p. 762-778Article in journal (Refereed)
    Abstract [en]

    In the present investigation, an age model of carbonate-rich cores from a seamount top in the Central Indian Basin (CIB) was constructed using both isotopic (230Thexcess, AMS 14C, oxygen isotopes) and biostratigraphic methods. The chronologies using the two methods are in good agreement, yielding a record of the late Middle Pleistocene to the Pleistocene-Holocene transition (550 to 11.5ka). The first appearance datum (FAD) of the radiolarian Buccinosphaera invaginata (180ka) and coccolith Emiliania huxleyi (268ka) and the last appearance datum (LAD) of the radiolarian Stylatractus universus (425ka) were used. A monsoon-induced productivity increase was inferred from carbonate, organic carbon and 13C records in response to the Mid-Brunhes Climatic Shift (MBCS), consistent with an increased global productivity. While the coccolith diversity increased, a decrease in coccolith productivity was found during the MBCS. At nearly the same time period, earlier records from the equatorial Indian Ocean, western Indian Ocean and eastern Africa have shown an increased productivity in response to the influence of westerlies and increased monsoon. The influence of easterlies from Australia and the intensification of aridity are evidenced by increased kaolinite content and clay-sized sediments in response to the MBCS. An increased abundance of Globorotalia menardii and other resistant species beginning from marine isotope stage (MIS) 11 and the proliferation of coccolith Gephyrocapsa spp. indicate increased dissolution, which is consistent with the widespread global carbonate dissolution during this period. The relatively high carbonate dissolution during the transition period of MIS 3/2 and glacial to interglacial periods (MIS 6, 7 and 8) may be due to the enhanced flow of corrosive Antarctic Bottom Water (AABW) into the CIB.

  • 96. Nath, B.N
    et al.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Selvaraj, K.
    Pereira, M.B.L
    Chen, C.T.A
    Be-10 variation in surficial sediments of the Central Indian Basin2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, p. 610-615Article in journal (Refereed)
    Abstract [en]

    Distribution of 10Be in systematically collected (degree × degree interval at 10 to 16 °S; 73.5 to 76.5 °E) surficial siliceous ooze, siliceous clay and pelagic clay sediments (top 2 cm) from the abyssal Central Indian Basin and the Andaman Sea is used to evaluate sources and to decipher the transport pathways of sediment particles, demarcate sediment depocenters and erosional areas. While 10Be concentrations display a wide variation (0.12–5.56 × 109 atoms g−1) with an average of 3.58 × 109 atoms g−1 in the Central Indian Basin, the values in the Andaman Sea are uniform with an average of 1.49 × 109 atoms g−1. The 10Be/9Be values in the Central Indian Basin sediments range between 0.06 and 2.99 × 10−8 atoms atoms−1 and average to 1.56 × 10−8 atoms atoms−1. Correlation of 10Be data with some selected major (Al, Mn, Ti) and trace (Rb and Ba) elements suggest that large part of the isotope has been supplied through direct atmospheric fallout from the water column and minor part from lithogenic detrital flux. Significantly lower 10Be accumulation rates in the Central Indian Basin and an order of magnitude higher in the Andaman Sea sediments compared to the estimated global average production rates indicate removal of the isotopes at the continental margins. Bottom topography seems to exert control on local 10Be variation, where sediments deposited in valleys or topographic depressions contain higher 10Be concentrations in contrast to the probably erosion-dominated areas at the slopes and troughs.

  • 97. Nath, Nagender
    et al.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. miljö-och landskapsdynamik.
    Gupta, S
    Borole, V
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Jonfysik.
    Tectonic control and the orbital forcing on the 3 million year sedimentary record from the Central Indian Basi2006Conference paper (Other (popular science, discussion, etc.))
  • 98. Nath, Nagender
    et al.
    Aldahan, Ala
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. ELD.
    Possnert, Göran
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Earth Sciences, Department of Earth Sciences, Environment and Landscape Dynamics. jonfysik.
    10Be variation in surficial sediment of the Central Indian Ocean2005In: 10th International conference on accelerator mass spectrometry, Berkeley, 2005, p. 32-Conference paper (Refereed)
  • 99. Nilsson, Andreas
    et al.
    Muscheler, Raimund
    Snowball, Ian
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Augustinus, Paul
    Atkin, Daniel
    Stephens, Tom
    Multi-proxy identification of the Laschamp geomagnetic field excursion in Lake Pupuke, New Zealand2011In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 311, no 1-2, p. 155-164Article in journal (Refereed)
    Abstract [en]

    We present palaeomagnetic and cosmogenic radionuclide records of the Laschamp geomagnetic excursion in Lake Pupuke, a maar lake in Auckland, New Zealand. Laschamp was identified by a combination of relative palaeointensity, (10)Be and (14)C data from the lake sediments and represents the first such record from the Southern Hemisphere. Despite the high organic carbon content, which causes relatively weak natural remanent magnetisations, the geomagnetic intensity minimum associated with the Laschamp excursion is identifiable as a relative palaeointensity minimum that is synchronous with (i) a peak in (10)Be concentration and (ii) an anomaly in Delta(14)C. The Lake Pupuke time scale, provided by (14)C data calibrated with INTCAL09, places the (10)Be maximum at the same time as a (10)Be maximum in Greenland ice cores when secured to the GICC05 time scale. The central age of the Laschamp geomagnetic excursion in Lake Pupuke as defined by the (10)Be prediction peak is c. 41 kyr, which confirms its global application as a palaeomagnetic isochron. Anomalous palaeomagnetic directional data at c. 32 kyr in the Lake Pupuke sediments may represent the Mono Lake geomagnetic excursion, but tephra layers caused by frequent eruptions in the Auckland volcanic field during this excursion probably disrupted the palaeointensity signal. The study highlights the value of combining traditional palaeomagnetic methods with measurements of cosmogenic radionuclides in the quest for accurate and precise geochronologies during MIS3, a time of rapid global climate change.

  • 100.
    Persson, S.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Afimov, V.
    Hou, X.
    I-129 Variability in precipitation over Europe2007In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 259, no 1, p. 508-512Article in journal (Refereed)
    Abstract [en]

    We present results and an overview of studies on I-129 in precipitation over Europe during the last decade, covering latitudes 37-70 degrees N. The data show about three orders of magnitude variability in concentrations but without specific correlation to latitude when all Europe is considered. The total amount of I-129 provided annually by precipitation over Europe composes only a tiny portion of the annual marine discharge but a significant portion of the gaseous discharges from the nuclear reprocessing facilities. Contribution of gaseous releases seems to be significant, although difficult to estimate. As shown by this study, a unified sampling procedure and systematic measurements of I-129 in precipitation throughout Europe are needed to achieve a coherent picture about the loading and sources of I-129 in precipitation and the atmosphere.

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