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  • 1
    Electronic Resource
    Electronic Resource
    Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Springer
    International journal of earth sciences 85 (1996), S. 577-585 
    Details
    ISSN: 1437-3262
    Keywords: Manganese nodules ; Thorium dating ; Uranium isotopes ; Peru basin ; TIMS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02369012
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    High-resolution210Pb dating of Lake Constance sediments: Stable lead in Lake Constance (1994)
    Springer
    Environmental geology 24 (1994), S. 267-274 
    Details
    ISSN: 1432-0495
    Keywords: 210Pb dating ; Lead ; Sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Two sediment cores (BO90/13b and BO90/17b) from Lake Constance were investigated byγ-spectrometry for210Pb,134Cs,137Cs,241Am,234Th, and other members of the238U decay chain. The sediments were dated using the constant-flux model for210Pb, and accumulation rates were determined. These range from 0.04 to 0.65g/cm 2/yr (BO90/13b) and 0.04 to 0.8g/cm 2/yr (BO90/17b), respectively. The mean accumulation rate amounts to 0.16g/cm 2/yr for both cores. The cores had already been dated by lamination counting and reconstruction of high-water events at the Limnological Institute at Constance, so that a very precise time scale was available. Both ages derived are in agreement within statistical error up to 1900, which means dating with the constant-flux model for210Pb was confirmed up to that age. The position of the maxima of bomb cesium and americium confirm the stratigraphic and210Pb datings. With241Am a further radioactive isotope is available, which can, due to the half-life of241Pu (t 1/2=14.4yr) be detected now byγ-spectrometry and can serve as an additional time indicator, the maximum being dated at 1963. By applying the various time scales, the depth profiles of stable lead and zinc of core BO90/13b were dated. Both heavy metals show a very significant maximum located beneath the layer of the maxima of bomb cesium and americium, showing that these maxima are older than those of the bomb isotopes. It is remarkable in this context that the maximum of zinc concentration occurs a little later than that of stable lead. Similar concentration profiles are observable in core BO90/17b and other, older sediment cores (CS6-CS10) on a transect across the lake. In contrast to a former assumption, the depth profile of stable lead in Lake Constance sediments does not reflect the anthropogenic gasoline lead emissions into the atmosphere for Germany, their maximum being dated at 1971.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00767087
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Springer
    Geologische Rundschau 85 (1996), S. 577-585 
    Details
    ISSN: 0016-7835
    Keywords: Key words Manganese nodules ; Thorium dating ; Uranium isotopes ; Peru basin ; TIMS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution 230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43-1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the 230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant 230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005310050098
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    Paper (German National Licenses)
    Fulltext
  • 4
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    Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Springer
    In:  Geologische Rundschau, 85 (3). pp. 577-585.
    Details
    Publication Date: 2018-03-21
    Description: Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1007/BF02369012
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 5
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    Protactinium determination in manganese crust VA13/2 by thermal ionization mass spectrometry (TIMS) (1999)
    Elsevier
    In:  Nuclear Instruments & Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 149 . pp. 353-360.
    Details
    Publication Date: 2017-02-13
    Description: Here we present the first high precision 231Protactinium measurements in a manganese crust applying thermal ionization mass spectrometry (TIMS) using the double filament technique. The detection limit using TIMS is at least one order of magnitude lower, the statistical uncertainty 6–8 times better than for α-spectrometry. Thus, older sections of manganese crust VA13/2 from the Northern Equatorial Pacific could be measured precisely for their 231Pa activity. Our results reveal significant variations in 231Paxs activity for the last 150 ka which corroborate existing α-spectrometric data. If the growth rate was constant between 0 and 450 ka, the protactinium flux from the water column into manganese encrustations must have been variable. Thus, 231Paxs is not suitable for dating marine Mn/Fe deposits.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/S0168-583X(98)00912-4
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
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    Data for: Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? (1996)
    Geologische Rundschau
    In:  EPIC3Heidelberg, Geologische Rundschau
    Details
    Publication Date: 2015-12-14
    Repository Name: EPIC Alfred Wegener Institut
    Type: PANGAEA Documentation , notRev
    Format: image/jpeg
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    PAPER (OA)
  • 7
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    Description of the manganese nodule analysed from station 63KG from SO79 cruise of R/V Sonne in the Central East Pacific Ocean (1996)
    PANGAEA
    Details
    Publication Date: 2023-08-28
    Keywords: BCR; Box corer (Reineck); Comment; Deposit type; DEPTH, sediment/rock; Description; GIK15561-1; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Peru Basin; Position; Quantity of deposit; Sample ID; Sediment type; SEDIPERU - TUSCH; Size; SO79; SO79_63KG; Sonne; Uniform resource locator/link to image
    Type: Dataset
    Format: text/tab-separated-values, 9 data points
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    DATA PANGAEA
  • 8
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    Description and 238U, 234U, 232Th and 230Th measurements of the manganese nodule analysed from station SO79_63KG, R/V SONNE (1996)
    PANGAEA
    In:  Supplement to: Bollhöfer, A; Eisenhauer, Anton; Frank, Norbert; Pech, D; Mangini, Augusto (1996): Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate? Geologische Rundschau, 85(3), 577-585, https://doi.org/10.1007/BF02369012
    Details
    Publication Date: 2023-08-28
    Description: Thorium and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution Th-230(excess) profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06-0.59 ppb (Th-230), 0.43-1.40 ppm (Th-232), 0.09-0.49 ppb (U-234) and 1.66-8.24 ppm (U-238). The uranium activity ratio in the uppermost samples (1-6 mm) and in two further sections in the nodule at 12.5+/-1.0 mm and 27.3-33.5 mm comes close to the present ocean wa ter value of 1.144+/-0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the Th-230(excess) concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant Th-230(excess) concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11-15 and 28-33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable sb supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
    Keywords: BCR; Box corer (Reineck); GIK15561-1; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Peru Basin; SEDIPERU - TUSCH; SO79; SO79_63KG; Sonne
    Type: Dataset
    Format: application/zip, 2 datasets
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    DATA PANGAEA
  • 9
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    Description of, and 238U, 234U, 232Th and 230Th measurements on a nodule from R/V Sonne station SO79_62KD, Central East Pacific Ocean (1999)
    PANGAEA
    In:  Supplement to: Bollhöfer, A; Frank, Norbert; Rohloff, S; Mangini, Augusto; Scholten, Jan Christoph (1999): A record of changing redox conditions in the northern Peru Basin during the Late Quaternary deduced from Mn/Fe and growth rate variations in two diagenetic manganese nodules. Earth and Planetary Science Letters, 170(4), 403-415, https://doi.org/10.1016/S0012-821X(99)00126-0
    Details
    Publication Date: 2023-08-28
    Description: Two diagenetic manganese nodules from the Peru Basin were investigated by thermal ionization mass spectrometry and high resolution alpha spectrometry for uranium and thorium. The TIMS concentrations for nodule 62KD (63KG) vary as follows: 0.12-1.01 ppb (0.06-0.59) 230Th, 0.51-1.98 ppm (0.43-1.40) 232Th, 0.13-0.80 ppb (0.09-0.49) 234U, and 1.95-13.47 ppm (1.66-8.24) 238U. Both nodules have average growth rates of ~110 mm per million years. However, from the variations of excess 230Th with depth we estimate partial accumulation rates which range from 50 to 400 mm per million years. The 234U dating method cannot be applied due to remobilization of U from the sediment and subsequent incorporation into the nodules' crystal lattice, reflected by decay corrected 234U values far above the ocean water value. Sections of fast nodule growth are related to those layers having high Mn/Fe ratios (up to 200) and higher densities. As a possible explanation we develop a scenario that describes similar glacial/interglacial trends in both nodules as a record of regional changes of sediment and/or deep water chemistry.
    Keywords: Dredge, box; DRG_B; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Peru Basin; SEDIPERU - TUSCH; SO79; SO79_62KD; Sonne
    Type: Dataset
    Format: application/zip, 3 datasets
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    DATA PANGAEA
  • 10
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    (Table 1, Page 579) Results of the 238U, 234U, 232Th and 230Th measurements on a nodule from station 63KG from SO79 cruise of R/V Sonne in the Central East Pacific Ocean (1996)
    PANGAEA
    Details
    Publication Date: 2023-08-28
    Keywords: BCR; Box corer (Reineck); Computed; DISTANCE; Distance, maximum; Distance, minimum; GIK15561-1; Identification; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; Peru Basin; SEDIPERU - TUSCH; SO79; SO79_63KG; Sonne; Thermal Ionization Mass Spectrometry (TIMS); Thorium-230; Thorium-230, standard deviation; Thorium-232; Thorium-232, standard deviation; Uranium-234; Uranium-234, standard deviation; Uranium-234/Uranium-238 activity ratio; Uranium-234/Uranium-238 activity ratio, standard deviation; Uranium-238; Uranium-238, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 221 data points
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    DATA PANGAEA
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