Change search
Refine search result
1 - 11 of 11
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Amakawa, Hiroshi
    et al.
    University of Tokyo.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Masuda, Akimasa
    University of Tokyo.
    Shimizu, Hiroshi
    University of Tokyo.
    Isotopic compositions of Ce, Nd and Sr in ferromanganese nodules from the Pacific and Atlantic Oceans, the Baltic and Barents Seas, and the Gulf of Bothnia1991In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 105, no 4, p. 554-565Article in journal (Refereed)
    Abstract [en]

    Ferromanganese nodules from the Pacific and Atlantic Oceans, the Barents and Baltic Seas, and the Gulf of Bothnia were analyzed for the isotopic compositions of Ce, Nd and Sr and the abundances of REE, Ba and Sr. REE patterns of Barents, Baltic and Bothnian samples show no Ce anomaly, or even a negative one, in contrast to the positive anomaly observed for the Pacific and Atlantic samples. Moreover, the Baltic and Bothnian samples have distinctly low εNd values; average εNd values of the four regions are as follows: Pacific -5, Barents -10, Atlantic -11 and Baltic inclusive of Gulf of Bothnia -19. The characteristic low εNd values of the Baltic samples are indicative of the influence of Precambrian rocks from the Baltic shield. Of particular interest is the feature of the Ce isotopic composition that εCe values of the samples from the Pacific are negative and those from the other three regions positive. This novel finding might suggest a difference in sources of Ce between the Pacific and other regions. These results demonstrate that Ce isotopic ratios can be a useful tracer in marine geochemistry, in combination with isotopic compositions of Nd and Sr.

  • 2.
    Andersson, Per S.
    et al.
    Swedish Museum of Natural History.
    Wasserburg, G.J.
    California Institute of Technology, Pasadena.
    Chen, J.H.
    California Institute of Technology, Pasadena.
    Papanastassiou, D.A.
    California Institute of Technology, Pasadena.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    238U234U and232Th230Th in the Baltic Sea and in river water1995In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 130, no 1-4, p. 217-234Article in journal (Refereed)
    Abstract [en]

    The concentration (C) of dissolved238U,234U,232Th and230Th in fresh and brackish waters from the Baltic Sea were determined using TIMS. The brackish waters range in salinity from that of sea water (SW) to 2.5‰. C238U in oxygen-saturated, surface waters is well correlated with salinity and shows quasi-conservative behavior, as does Sr. Samples from the redox water interface show depletion in C238U, demonstrating that dissolved U is being removed by FeMn oxyhydroxides. From a simple mixing relationship for the brackish water,δ234U* = 1000‰ was calculated for the fresh water source in the northern Baltic. A study of the Kalixälven River over an annual cycle yields highδ234U during spring and summer discharge and lower values during fall and winter, showing that different sources contribute to the U load in the river during different seasons. C232Th and C230Th in river water are governed by the discharge, reflecting the importance of the increased abundance of small particles ( < 0.45 μm) for the232Th230Th load at high discharge.232Th/238U in river water is about 40 times less than in detrital material. In the brackish water, C232Th drops 2 orders of magnitude in the low salinity region ( < 5‰), reaching a value close to that of sea water at a salinity of 7.5‰. Almost all of the riverine232Th must be deposited in the low-salinity regions of the estuary. The230Th/232Th in river waters is about twice the equilibrium value for232Th/238U (3.8). In the brackish waters,230Th/232Th is greater by a factor of 10-100 than both river water and SW. The big increase in230Th/232Th in the Baltic Sea waters over the riverine input indicates that the Th isotopes enter the estuary as a mixture of two carrier phases. We infer that about 96% of232Th in river water is carried by detrital particles, whereas the other phase (solution, colloidal) has a much higher232Th/232Th. Entering the estuary, the detrital particles sediment out rapidly, whereas the non-detrital phase is removed more slowly, causing a marked increase in230Th/232Th in the brackish water. In SW,230Th/232Th is closer to river input and detrital material than in brackish water. We conclude that in the deep sea,232Th is almost exclusively dominated by windblown dust and can be used to monitor dust flux. The230Th excess in Baltic rivers is produced in U-rich,232Th-poor peatlands and trapped in authigenic particles and transported with the particles. Time scales for producing the230Th excess are ≈ 2000-8000 yr. This is younger than, but comparable to, the time of the latest deglaciation, which ended some 9000 yr ago when the mires were forming. These results have implications for the possible mobility of actinides stored in repositories

  • 3.
    Andersson, Per S.
    et al.
    California Institute of Technology, Pasadena.
    Wasserburg, G.J.
    California Institute of Technology, Pasadena.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The sources and transport of Sr and Nd isotopes in the Baltic Sea1992In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 113, no 4, p. 459-472Article in journal (Refereed)
    Abstract [en]

    We have determined the concentration and isotopic composition of Sr and Nd in waters from the Baltic Sea. The Baltic Sea is an intracontinental, stratified, brackish water, estuarine-like system, and the rivers emptying into it drain a suite of terranes ranging from Proterozoic-Archean in the north to Phanerozoic in the south. The sampled brackish waters range in salinity from seawater (SW) at 35.289‰ to a minimum of 2.460‰ at the surface in the innermost part of the Gulf of Bothnia. The Sr concentrations show generally conservative behavior, indicating a simple two-component mixing. However, small deviations (3-70 ‰) from a perfect mixing line reveal that the imprints from rivers with different Sr concentrations are preserved in the blending. Strontium concentrations from a depth profile across the redoxcline in the Baltic proper indicate that vertical particle transport alters the Sr concentration in the water. Our estimated concentration of Sr in the average freshwater input to the Baltic is 0.03 ppm, which is only about 0.4% of the SW concentration. The Sr isotopic data range from εSr(SW) = 0 in seawater to εSrBW(SW) = 7.8 in the least saline Baltic water (BW) sample in the Gulf of Bothnia. The isotopic composition of Sr versus 1/Sr in the Baltic Sea follows an almost perfect mixing line, which shows that seawater Sr is mixed with much more radiogenic components. Calculated end-member values of εSr*(SW) for each sample show that the riverine input into the Gulf of Bothnia has εSr*(SW) = 120-200and10-50 ε units in the Baltic proper. These values are in general agreement with direct measurements of river waters in each region. However, the calculated values in the Gulf of Bothnia are lower than the measured river water input in this region, which indicates the presence of less radiogenic Sr, presumably originating from the river waters draining the southern part of the basin which are partially transported northward and mixed with Sr from the Gulf of Bothnia rivers. The Nd concentration in the Baltic Sea is not conservative, varying between 5 and 45 ppt, with the highest concentrations in the bottom waters due to vertical particulate transport. A plot of εNd(O) in Baltic water yields a good correlation with the calculated freshwater end member εSr*(SW). The data show that it is possible to unravel the different freshwater sources into the Baltic and to identify the zones of particulate removal of both non-conservative species such as the REE and of quasi-conservative species such as Sr. The use of isotopic tracers in this estuarine environment may provide a much better insight into mixing and element transport. It should also be possible to trace lateral movements of freshwater inputs

  • 4.
    Andersson, Per S.
    et al.
    California Institute of Technology, Pasadena.
    Wasserburg, G.J.
    California Institute of Technology, Pasadena.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Stordal, Mary C.
    Texas A&M University at Galveston.
    Strontium, dissolved and particulate loads in fresh and brackish waters: the Baltic Sea and Mississippi delta1994In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 124, no 1-4, p. 195-210Article in journal (Refereed)
    Abstract [en]

    A study was conducted of the isotopic composition and concentration of Sr and of major elements in dissolved and suspended loads of fresh and brackish waters. The purpose was to establish the contributions of different parent rocks and minerals to Sr during weathering and transport and to identify the role of Fe_Mn oxyhydroxides in the redistribution of Sr in the water column during the sedimentary cycle. Studies were conducted on a profile across an oxic-anoxic boundary in the Baltic and on rivers covering behavior over an annual cycle. In general, the 87Sr/86Sr ratios differ between particulate and dissolved loads, with more radiogenic Sr in the particulate loads. These differences are attributed to differential weathering of minerals, where high Rb/Sr minerals dominate the particulate load and low Rb/Sr the dissolved load. There is broad correlation of 87Sr/86Sr with K/Al in the suspended load. The differences in 87Sr/86Sr between suspended and dissolved load are highly variable and are related to the Fe or Mn concentration on the particulates. In samples with high Fe/Al, the difference becomes small. A good correlation was found between Sr/Al and Fe/Al or Mn/Al in the particulates both in brackish and fresh waters. Sr is removed from solution both in rivers and in the Baltic Sea whenever there is formation of Fe_Mn oxyhydroxide particulates. This precipitation greatly diminishes the difference in isotopic composition of the dissolved and suspended loads. As the particles containing Fe_Mn oxyhydroxides settle, they dissolve in anoxic zones and release Sr. This provides a mechanism for Sr redistribution in the water column. Sr is thus only quasi-conservative in environments where Fe_Mn oxyhydroxides form or dissolve. From consideration of the isotopic differences in Sr between dissolved and suspended loads, it follows that the net Sr input depends upon weathering characteristics of the contributing mineral phases. Changes in weathering mechanisms due to climate change may cause Sr isotopic shifts in the marine environment.

  • 5.
    D'Agrella-Filho, Manoel S.
    et al.
    Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo.
    Tohver, Eric
    School of Earth and Geographical Sciences, University of Western Australia, Crawley.
    Santos, João O.S.
    Redstone Resources Limited, Perth.
    Elming, Sten-åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Trinidade, Ricardo I.F.
    Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo.
    Pacca, Igor I.G.
    Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo.
    Geraldes, Mauro C.
    Faculdade de Geologia, Universidade do Estado do Rio de Janeiro.
    Direct dating of paleomagnetic results from Precambrian sediments in the Amazon craton: Evidence for Grenvillian emplacement of exotic crust in SE Appalachians of North America2008In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 267, no 1-2, p. 188-199Article in journal (Refereed)
    Abstract [en]

    We apply a new diagenetic dating technique to determine the age of magnetization for Precambrian sedimentary rocks in the SW Amazon craton. Two new palcomagnetic poles are reported from the rocks of the Aguapei Gp.: red beds of the Fortuna Fm. (P-lat = 59.8 degrees N, P-lon = 155.9 degrees E, A(95)=9.5, K= 14, 18 sites, N/n 128/115, Q=5) and the reverse-polarity mudstones of the overlying Vale da Promissao Formation (P-lat=49.5 degrees N, P-lon = 89.3 degrees E, A(95) = 12.5, K=30, 6 sites, N/n=94/80, Q=4). The Fortuna Fm. magnetization is hosted by massive, interstitial hematite cement and constitutes a post-depositional remanence. The age of diagenesis of the red beds is well-constrained by the 1149 +/- 7 Ma U-Pb age of authigenic xenotime rims on detrital zircons determined by SHRIMP analysis. The magnetite-hosted remanence of the Vale da Promissao Fm. may be detrital in origin, but the age of deposition is poorly constrained. The reliable and precisely-dated Fortuna Fun. pateomagnetic pole fixes the paleogeographic position of the Amazon craton near the SE Appalachians portion of North America at 1.15 Ga. These data demonstrate a mobile Grenvillian link between these two cratons, and support the recent identification of Amazon crust in the Blue Ridge province region of North America

  • 6.
    Dahlqvist, Ralf
    et al.
    Laboratory for Isotope Geology. Swedish Museum of Natural History, Stockholm.
    Andersson, Per S.
    Luleå tekniska universitet.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The concentration and isotopic composition of diffusible Nd in fresh and marine waters2005In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 233, no 1-2, p. 9-16Article in journal (Refereed)
    Abstract [en]

    Variations in the Nd isotopic composition of ocean water through time, recorded in marine deposits, are suggested to document changes in erosional input and ocean circulation. Thus characterization of the dissolved Nd component in seawater is important. But few attempts have been made to directly measure truly dissolved Nd. Here we report Nd data, obtained using the technique of diffusive gradients in thin-films (DGT) designed to measure in situ, diffusible labile trace metals in aqueous solutions. The method samples free ions and possibly very small complexes. The concentration and isotopic composition of Nd in fresh, brackish and seawater have been determined with DGT, analyzed with thermal ionization mass-spectrometry, and compared with filtered and bulk water samples. Concentrations measured in water samples and with DGT show that the relative amount of diffusible Nd increases with salinity, from being about 10% in the fresh water to 42% in seawater. At each sampled site, the isotopic composition of Nd in the water shows a similar isotopic composition, within errors, with Nd sampled using the DGT method. These results indicate that there is a complete exchange between the particulate/colloidal fraction and the truly dissolved phase. Therefore our findings suggest that solute Nd reflects both the isotopic composition of the marine sediments and the bulk water.

  • 7.
    Donadini, Fabio
    et al.
    Institut für Geophysik, ETH Zürich.
    Elming, Sten-Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Tauxe, Lisa
    Scripps Institution of Oceanography, University of California, San Diego.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Mineralogy.
    Paleointensity determination on a 1.786 Ga old gabbro from Hoting, Central Sweden2011In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 309, no 3-4, p. 234-248Article in journal (Refereed)
    Abstract [en]

    Paleointensities from Precambrian rocks are rare and might be biased by remagnetization processes. Here we present new analyses of samples from a 1.786 Ga gabbro near Hoting, Central Sweden. Rock magnetic and mineralogical analyses indicate that one of the sites (site 5) may be pristine, whereas the others exhibit evidence of alteration. Characteristic remanent magnetization was determined using principal component analysis for each sample and was compared with results obtained in a previous study of Elming et al. (2009). Intensity measurements from site 5 show higher values compared to those of the other sites, suggesting that alteration processes may lead to underestimation of the field intensity. After cooling rate and anisotropy correction, the field moment at 1.786 Ga was estimated to be 25.6 ± 3.3 ZAm2 and 15.2 ± 6.1 ZAm2 from site 5 only and from all sites respectively. We consider the result from site 5 to be more accurate owing to the lack of evidence for alteration; our estimates agree well with the Proterozoic VDM values suggested by Biggin et al. (2009).

  • 8.
    Døssing, Arne
    et al.
    DTU Space, National Space Institute, Technical University of Denmark.
    Jackson, H. Ruth
    Geological Survey of Canada Atlantic (GSCA), Halifax.
    Matzka, Jürgen
    National Space Institute, DTU Space.
    Einarsson, Indridi
    National Space Institute, DTU Space.
    Rasmussen, Thorkild Maack
    Geological Survey of Denmark and Greenland (GEUS) .
    Brozena, John M.
    Naval Research Laboratory.
    On the origin of the Amerasia Basin and the High Arctic Large Igneous Province-Results of new aeromagnetic data2013In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 363, p. 219-230Article in journal (Refereed)
    Abstract [en]

    The history of the 2.5 million km2 Amerasia Basin (sensu lato) is in many ways the least known in the global tectonic system. Radically different hypotheses proposed to explain its origin are supported only by inconclusive and/or indirect observations and several outstanding issues on the origin of the Basin remain unaddressed. The difficulty lies in the geodynamic evolution and signature of the Basin being overprinted by excess volcanism of the Alpha-Mendeleev Ridge complex, part of the High Arctic Large Igneous Province (HALIP) and one of the largest (>1 million km2) and most intense magmatic and magnetic complexes on Earth. Here, we present the results of a 550,000km2 aerogeophysical survey over the poorly explored Lomonosov Ridge (near Greenland) and adjoining Amerasia and Eurasia Basins that provides the first direct evidence for consistent linear magnetic features between the Alpha and Lomonosov Ridges, enabling the tectonic origin of both the Amerasia Basin and the HALIP to be constrained. A landward Lower Cretaceous ( ~ 138 - 125(120) Ma) giant dyke swarm (minimum 350×800km2) and tentative oceanward Barremian (or alternatively lower Valanginian-Barremian) seafloor spreading anomalies are revealed. Prior to Cenozoic opening of the Eurasia Basin the giant dyke swarm stretched from Franz Josef Land to the southern Alpha Ridge and possibly further to Queen Elisabeth Islands, Canada. The swarm points towards a 250-km-wide donut-shaped anomaly on the southern Alpha Ridge, which we propose was the centre of the HALIP mantle plume, suggesting that pronounced intrusive activity, associated with an Alpha Ridge mantle plume, took place well before the Late Cretaceous Superchron and caused continental breakup in the northern Amerasia Basin. Our results imply that at least the southern Alpha Ridge as well as large parts of the area between the Lomonosov and southern Alpha Ridges are highly attenuated continental crust formed by poly-phase breakup with LIP volcanic addition. Significantly, our results are consistent with an early ( ~ pre-120 Ma) overall continental scale rotational opening of the Amerasia Basin in which the Eurasian continental margin is rifted from the Canadian-southern Alpha Ridge margin about one or more poles in the Mackenzie Delta (Alaska). The findings provide a key to resolving Arctic plate reconstructions and LIPs in the Mesozoic.

  • 9.
    Ingri, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Malinovskiy, Dmitry
    Rodushkin, Ilia
    Baxter, Douglas
    Widerlund, Anders
    Andersson, Per
    Laboratory for Isotope Geology. Swedish Museum of Natural History, Stockholm.
    Gustafsson, Örjan
    Institute of Applied Environmental Research (ITM), Stockholm University.
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Iron isotope fractionation in river colloidal matter2006In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 245, no 3-4, p. 792-798Article in journal (Refereed)
    Abstract [en]

    Temporal variations in the iron isotopic composition, δ56Fe between − 0.13‰ and 0.31‰, have been measured in the suspended fraction in a Boreal river. The major mechanism behind these variations is temporal mixing between two types of particles–colloids, Fe-oxyhydroxides and Fe–C colloids. Data in this study indicate that these two types of colloids have different Fe-isotope composition. The Fe–C colloid has a negative δ56Fe value whereas the Fe-oxyhydroxide colloid is enriched in 56Fe. These two types of colloidal matter have different hydrogeochemical origin. The Fe–C colloid reaches the river during storm events when the upper sections of the soil profile (O and E horizons) are flooded by a rising water table. Colloidal Fe-oxyhydroxides reach the river via inflow and subsequent oxidation of groundwater enriched in dissolved Fe(II).

  • 10.
    Loberg, Bengt E.H.
    Luleå tekniska universitet.
    A Proterozoic subduction zone in southern Sweden1980In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 46, no 2, p. 287-294Article in journal (Refereed)
    Abstract [en]

    Optical microscopy and chemical analyses for major and trace elements have been performed on 27 Proterozoic metavolcanics from southern Sweden. The metavolcanics and associated metasediments are part of a large arced structure around a vast region with granitic batholiths. The compositional data show that the rocks are altered basalts and andesites and the Si, Ti, Zr and Cr relations demonstrate that almost half of the metabasalts are in accordance with present day arc volcanics and that another large fraction represents ocean floor tholeiites. These relations suggest that major plate tectonic processes occurred already during the Proterozoic in southern Sweden and that during these processes arc volcanics and ocean floor basalts were mixed at a subduction zone.

  • 11.
    Rehkämper, Mark
    et al.
    ETH Zurich.
    Frank, M.
    ETH Zurich.
    Hein, J.R.
    U.S. Geological Survey.
    Porcelli, D.
    ETH Zurich.
    Halladay, A.
    ETH Zurich.
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Liebetrau, V.
    GEOMAR.
    Thallium isotope variations in seawater and hydrogenetic, diagenetic, and hydrothermal ferromanganese deposits2002In: Earth and Planetary Science Letters, ISSN 0012-821X, E-ISSN 1385-013X, Vol. 197, no 1-2Article in journal (Refereed)
    Abstract [en]

    Results are presented for the first in-depth investigation of Tl isotope variations in marine materials. The Tl isotopic measurements were conducted by multiple collector-inductively coupled plasma mass spectrometry for a comprehensive suite of hydrogenetic ferromanganese crusts, diagenetic Fe-Mn nodules, hydrothermal manganese deposits and seawater samples. The natural variability of Tl isotope compositions in these samples exceeds the analytical reproducibility (±0.05‰) by more than a factor of 40. Hydrogenetic Fe-Mn crusts have ε205Tl of +10 to +14, whereas seawater is characterized by values as low as -8 (ε205Tl represents the deviation of the 205Tl/203Tl ratio of a sample from the NIST SRM 997 Tl isotope standard in parts per 104). This 2‰ difference in isotope composition is thought to result from the isotope fractionation that accompanies the adsorption of Tl onto ferromanganese particles. An equilibrium fractionation factor of α1.0021 is calculated for this process. Ferromanganese nodules and hydrothermal manganese deposits have variable Tl isotope compositions that range between the values obtained for seawater and hydrogenetic Fe-Mn crusts. The variability in ε205Tl in diagenetic nodules appears to be caused by the adsorption of Tl from pore fluids, which act as a closed-system reservoir with a Tl isotope composition that is inferred to be similar to seawater. Nodules with ε205Tl values similar to seawater are found if the scavenging of Tl is nearly quantitative. Hydrothermal manganese deposits display a positive correlation between ε205Tl and Mn/Fe. This trend is thought to be due to the derivation of Tl from distinct hydrothermal sources. Deposits with low Mn/Fe ratios and low ε205Tl are produced by the adsorption of Tl from fluids that are sampled close to hydrothermal sources. Such fluids have low Mn/Fe ratios and relatively high temperatures, such that only minor isotope fractionation occurs during adsorption. Hydrothermal manganese deposits with high Mn/Fe and high ε205Tl are generated by scavenging of Tl from colder, more distal hydrothermal fluids. Under such conditions, adsorption is

1 - 11 of 11
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf