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  • PANGAEA  (88)
  • Geological Society of America (GSA)
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  • 1
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    PANGAEA
    In:  Supplement to: Frank, Martin; Eckhardt, Joerg-Detlef; Eisenhauer, Anton; Kubik, Peter W; Dittrich-Hannen, Beate; Segl, Monika; Mangini, Augusto (1994): Beryllium 10, thorium 230, and protactinium 231 in Galapagos microplate sediments: Implications of hydrothermal activity and paleoproductivity changes during the last 100,000 years. Paleoceanography, 9(4), 559-578, https://doi.org/10.1029/94PA01132
    Publication Date: 2023-05-12
    Description: Biogenic particle fluxes from highly productive surface waters, boundary scavenging, and hydrothermal activity are the main factors influencing the deposition of radionuclides in the area of the Galapagos microplate, eastern Equatorial Pacific. In order to evaluate the importance of these three processes throughout the last 100 kyr, concentrations of the radionuclides 10Be, 230Th, and 231Pa, and of Mn and Fe were measured at high resolution in sediment samples from two gravity cores KLH 068 and KLH 093. High biological productivity in the surface waters overlying the investigated area has led to 10Be and 231Pa fluxes exceeding production during at least the last 30 kyr and probably the last 100 kyr. However, during periods of high productivity at the up welling centers off Peru and extension of the equatorial high-productivity zone, a relative loss of 10Be and 231Pa may have occurred in these sediment cores because of boundary scavenging. The effects of hydrothermal activity were investigated by comparing the 230Thex concentrations to the Mn/Fe ratios and by comparing the fluxes of 230Th and 10Be which exceed production. The results suggest an enhanced hydrothermal influence during isotope stages 4 and 5 and to a lesser extent during isotope stage 1 in core KLH 093. During isotope stages 2 and 3, the hydrothermal supply of Mn was deposited elsewhere, probably because of changes in current regime or deep water oxygenation. A strong increase of the Mn/Fe ratio at the beginning of climatic stage 1 which is not accompanied by an increase of the 230Thex concentration is interpreted to be an effect of Mn remobilization and reprecipitation in the sediment.
    Keywords: Equatorial East Pacific; HYMAS II; KAL; Kasten corer; KLH068; KLH093; SO60; SO60_68; SO60_93; Sonne
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 2
    Publication Date: 2023-05-12
    Keywords: AGE; Alpha spectrometry; Aluminium oxide; Beryllium-10; Beryllium-10, standard deviation; Calcium carbonate; Density, dry bulk; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Equatorial East Pacific; HYMAS II; Iron oxide, Fe2O3; Isotope ratio mass spectrometry; KAL; Kasten corer; KLH093; Manganese oxide; Neogloboquadrina dutertrei, δ18O; Protactinium-231; Protactinium-231, standard deviation; SO60; SO60_93; Sonne; Thorium-230, supported, uncorrected; Thorium-230, supported, uncorrected standard deviation; Thorium-230 excess; Thorium-230 excess, 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; X-ray fluorescence (XRF)
    Type: Dataset
    Format: text/tab-separated-values, 1426 data points
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  • 3
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    PANGAEA
    In:  Supplement to: Ceccaroni, L; Frank, Martin; Frignani, M; Langone, Leonardo; Ravaioli, Mariangela; Mangini, Augusto (1998): Late Quaternary fluctuations of biogenic component fluxes on the continental slope of the Ross Sea, Antarctica. Journal of Marine Systems, 17(1-4), 515-525, https://doi.org/10.1016/S0924-7963(98)00061-X
    Publication Date: 2023-05-12
    Description: A sediment core, collected from the western part of the continental slope of the Ross Sea at 2380 m water depth, records events of the last two climatic cycles (250 kyr). A 230Thex-based chronology was obtained and boundaries of the isotope stages were set assuming that biological productivity was enhanced during periods of less ice cover. Then, 230Thex0, organic carbon, biogenic silica and biogenic Ba distributions were compared to the glacial-interglacial stage boundaries and corresponding ages of the delta18O record of Martinson et al. [Martinson et al., 1987, doi:10.1016/0033-5894(87)90046-9]. Sediment accumulation rates ranged between 1.2 cm kyr**-1 in the isotope stage 6 and 3.8 cm kyr**-1 during the Holocene. Variations in the concentrations and fluxes of organic carbon, biogenic Ba, biogenic silica and Mn gave information on palaeoclimate changes. Processes of sediment redistribution in the Ross Sea margin were enlightened from a comparison of the measured and expected fluxes of 230Thex. Calculation of the focusing-corrected accumulation rates of biogenic Ba enabled us to evaluate the export palaeoproductivity. Corrected accumulation rates of biogenic components and calculated palaeoproductivities were low, compared to the Antarctic Polar Front in the Atlantic sector, throughout the last two climatic cycles. Glacial-interglacial changes of sea ice cover and ventilation of the Ross Sea were probably major causes of variations in biogenic particle flux and distribution of redox-sensitive elements within the sediment column.
    Keywords: ANTA91-8; GC; Gravity corer; Silicon Cycling in the World Ocean; SINOPS
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 4
    Publication Date: 2023-05-12
    Keywords: Age, maximum/old; Age, minimum/young; Age model, Martinson et al (1987); ANTA91-8; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; GC; Gravity corer; Isotopic event; Sedimentation rate; Silicon Cycling in the World Ocean; SINOPS
    Type: Dataset
    Format: text/tab-separated-values, 48 data points
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  • 5
    Publication Date: 2023-05-12
    Keywords: 17M17; BC; Box corer; Calcium carbonate; CIM (Cooperative Investigations of the Mediterranean); Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Description; Ionian Sea; M17; M17_17; Meteor (1964); Thorium-230; Thorium-230, standard deviation; Thorium-232; Thorium-232, standard deviation; Uranium-238; Uranium-238, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 106 data points
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  • 6
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    PANGAEA
    In:  Supplement to: Schimpf, Daniel; Kilian, Rolf; Kronz, Andreas; Simon, Klaus; Spötl, Christoph; Wörner, Gerhard; Deininger, Michael; Mangini, Augusto (2011): The significance of chemical, isotopic, and detrital components in three coeval stalagmites from the superhumid southernmost Andes (53°S) as high-resolution palaeo-climate proxies. Quaternary Science Reviews, 30(3-4), 443-459, https://doi.org/10.1016/j.quascirev.2010.12.006
    Publication Date: 2023-05-12
    Description: Stalagmites are important palaeo-climatic archives since their chemical and isotopic signatures have the potential to record high-resolution changes in temperature and precipitation over thousands of years. We present three U/Th-dated records of stalagmites (MA1–MA3) in the superhumid southern Andes, Chile (53°S). They grew simultaneously during the last five thousand years (ka BP) in a cave that developed in schist and granodiorite. Major and trace elements as well as the C and O isotope compositions of the stalagmites were analysed at high spatial and temporal resolution as proxies for palaeo-temperature and palaeo-precipitation. Calibrations are based on data from five years of monitoring the climate and hydrology inside and outside the cave and on data from 100 years of regional weather station records. Water-insoluble elements such as Y and HREE in the stalagmites indicate the amount of incorporated siliciclastic detritus. Monitoring shows that the quantity of detritus is controlled by the drip water rate once a threshold level has been exceeded. In general, drip rate variations of the stalagmites depend on the amount of rainfall. However, different drip-water pathways above each drip location gave rise to individual drip rate levels. Only one of the three stalagmites (MA1) had sufficiently high drip rates to record detrital proxies over its complete length. Carbonate-compatible element contents (e.g. U, Sr, Mg), which were measured up to sub-annual resolution, document changes in meteoric precipitation and related drip-water dilution. In addition, these soluble elements are controlled by leaching during weathering of the host rock and soils depending on the pH of acidic pore waters in the peaty soils of the cave's catchment area. In general, higher rainfall resulted in a lower concentration of these elements and vice versa. The Mg/Ca record of stalagmite MA1 was calibrated against meteoric precipitation records for the last 100 years from two regional weather stations. Carbonate-compatible soluble elements show similar patterns in the three stalagmites with generally high values when drip rates and detrital tracers were low and vice versa. d13C and d18O values are highly correlated in each stalagmite suggesting a predominantly drip rate dependent kinetic control by evaporation and/or outgassing. Only C and O isotopes from stalagmite MA1 that received the highest drip rates show a good correlation between detrital proxy elements and carbonate-compatible elements. A temperature-related change in rainwater isotope values modified the MA1 record during the Little Ice Age (~0.7–0.1 ka BP) that was ~1.5 °C colder than today. The isotopic composition of the stalagmites MA2 and MA3 that formed at lower drip rates shows a poor correlation with stalagmite MA1 and all other chemical proxies of MA1. 'Hendy tests' indicate that the degassing-controlled isotope fractionation of MA2 and MA3 had already started at the cave roof, especially when drip rates were low. Changing pathways and residence times of the seepage water caused a non-climatically controlled isotope fractionation, which may be generally important in ventilated caves during phases of low drip rates. Our proxies indicate that the Neoglacial cold phases from ~3.5 to 2.5 and from ~0.7 to 0.1 ka BP were characterised by 30% lower precipitation compared with the Medieval Warm Period from 1.2 to 0.8 ka BP, which was extremely humid in this region.
    Keywords: Age, dated; Age, dated standard deviation; Age, Uranium-Thorium; Chile; DISTANCE; Event label; Laboratory number; MA1; MA2; MA3; Marcello_Arevalo_1; Marcello_Arevalo_2; Marcello_Arevalo_3; Speleothem sample; SPS; Thermal Ionization Mass Spectrometry (TIMS); Thorium-230; Thorium-230, standard deviation; Thorium-232; Thorium-232, standard deviation; Uranium-238; Uranium-238, standard deviation; δ234 Uranium; δ234 Uranium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 528 data points
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  • 7
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    PANGAEA
    In:  Supplement to: Spötl, Christoph; Mangini, Augusto (2002): Stalagmite from the Austrian Alps reveals Dansgaard-Oeschger events during istotope stage 3: implications for the absolute chronology of Greenland ice cores. Earth and Planetary Science Letters, 203(1), 507-518, https://doi.org/10.1016/S0012-821X(02)00837-3
    Publication Date: 2023-05-12
    Description: A mass-spectrometric uranium-series dated stalagmite from the Central Alps of Austria provides unprecedented new insights into high-altitude climate change during the peak of isotope stage 3. The stalagmite formed continuously between 57 and 46 kyr before present. A series of 'Hendy tests' demonstrates that the outer parts of the sample show a progressive increase of both stable C and O isotope values. No such covariant increase was detected within the axial zone. This in conjunction with other observations suggests that the continuous stable oxygen isotope profile obtained from the axial zone of the stalagmite largely reflects the unaltered isotopic composition of the cave drip water. The delta18O record shows events of high delta18O values that correlate remarkably with Interstadials 15 (a and b), 14 and 12 identified in the Greenland ice cores. Interstadial 15b started rapidly at 55.6 kyr and lasted ~300 yr only, Interstadial 15a peaked 54.9 kyr ago and was even of shorter duration (~100 yr), and Interstadial 14 commenced 54.2 kyr ago and lasted ~3000 yr. This stalagmite thus represents one of the first terrestrial archives outside the high latitudes which record precisely dated Dansgaard-Oeschger (D/O) events during isotope stage 3. Provided that rapid D/O warmings occurred synchronously in Greenland and the European Alps, the new data provide an independent tool to improve the GRIP and GISP2 chronologies.
    Keywords: Age, dated; Age, dated standard deviation; Age, Uranium-Thorium; Austria; DISTANCE; Kleegruben_Cave_SPA49; Mass spectrometer Finnigan MAT 262; Sample, optional label/labor no; speleothem; Speleothem sample; SPS; Thorium-230; Thorium-230, standard deviation; Thorium-232; Thorium-232, standard deviation; Uranium-238; Uranium-238, standard deviation; δ234 Uranium; δ234 Uranium, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 165 data points
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  • 8
    Publication Date: 2023-05-12
    Keywords: Age, maximum/old; Age, minimum/young; Age, standard deviation; Age model; Age model, Martinson et al (1987); Age model, optional; Alpha spectrometry; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Electron spin resonance (ESR); Equatorial East Pacific; HYMAS II; KAL; Kasten corer; KLH093; Potassium; SO60; SO60_93; Sonne; Thorium-230 excess; Thorium-230 excess, standard deviation; Uranium-234; Uranium-234, standard deviation
    Type: Dataset
    Format: text/tab-separated-values, 60 data points
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  • 9
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    PANGAEA
    In:  Supplement to: Frank, Martin; Gersonde, Rainer; Rutgers van der Loeff, Michiel M; Bohrmann, Gerhard; Nürnberg, Christine Caroline; Kubik, Peter W; Suter, Martin; Mangini, Augusto (2000): Similar glacial and interglacial export bioproductivity in the Atlantic sector of the Southern Ocean: multiproxy evidence and implications for atmospheric CO2. Paleoceanography, 15(6), 642-658, https://doi.org/10.1029/2000PA000497
    Publication Date: 2023-06-27
    Description: We present time series of export productivity proxy data including 230Thex-normalized deposition rates (rain rates) of 10Be, dissolution-corrected biogenic Ba, and biogenic opal as well as authigenic U concentrations which are complemented by rain rates of total (detrital) Fe and sea ice indicating diatom abundances from five sediment cores across the Atlantic sector of the Southern Ocean covering the past 150,000 years. The results suggest that 10Be rain rates and authigenic U concentration cannot serve as quantitative paleoproductivity proxies because they have also been influenced by detrital particle fluxes in the case of 10Be and bulk sedimentation rates (sediment focussing) and deep water oxygenation in the case of U. The combined results of the remaining productivity proxies of this study (rain rates of biogenic opal and biogenic Ba in those sections without authigenic U) and other previously published proxy data from the Southern Ocean (231Pa/230Th and nitrogen isotopes) suggest that a combination of sea ice cover, shallow remineralization depth, and stratification of the glacial water column south of the present position of the Antarctic Polar Front and possibly Fe fertilization north of it have been the main controlling factors of export paleoproductivity in the Southern Ocean over the last 150,000 years. An overall glacial increase of export paleoproductivity is not supported by the data, implying that bioproductivity variations in the Southern Ocean are unlikely to have contributed to the major glacial atmospheric CO2 drawdown observed in ice cores.
    Keywords: ANT-VIII/3; AWI_MarGeoChem; AWI_Paleo; Giant box corer; GKG; Gravity corer (Kiel type); Marine Geochemistry @ AWI; Meteor Rise; MUC; MultiCorer; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Polarstern; PS16; PS16/278; PS16/284; PS16/311; PS1754-1; PS1754-2; PS1756-5; PS1756-6; PS1768-1; PS1768-8; SFB261; Shona Ridge; Silicon Cycling in the World Ocean; SINOPS; SL; South Atlantic in Late Quaternary: Reconstruction of Budget and Currents
    Type: Dataset
    Format: application/zip, 6 datasets
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  • 10
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    PANGAEA
    In:  Supplement to: Hoffmann, Dirk L; Woda, Clemens; Lomitschka, Michael; Mangini, Augusto (1999): Untersuchungen zur ESR-Datierung eemzeitlicher Muscheln aus Schleswig-Holstein = ESR-dating of eemian bivalves from Schleswig-Holstein. Meyniana, 51, 113-124, https://doi.org/10.2312/meyniana.1999.51.117
    Publication Date: 2023-06-27
    Description: The ESR dating method was applied to marine shells taken from a sediment core from Dagebüll, Schleswig-Holstein. Four samples from two different depths of the core (17.5 m and 25-26 m), separated by a 2.76 meter thick clay layer (Turritella Clay), yielded identical ages within the limits of error. They indicated an assignment to the oxygen isotope stage 5, thus confirming the stratigraphic age. In addition, the ESR-ages confirm the interpretation of Lomitschka et al. (1997, doi:10.2312/meyniana.1997.49.85), that the Th/U-ages of shells below the clay layer are reliable, whereas shells located above the clay layer, which were strongly influenced by percolating groundwaters of an open system, yielded falsified Th/U-ages.
    Keywords: DA-1; DRILL; Drilling/drill rig; GIK14350-1; GIK-cruise; Hauke-Haien-Koog, Dagebüll, Schleswig-Holstein, Germany
    Type: Dataset
    Format: application/zip, 3 datasets
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