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PANGAEA - Publishing Network for Geoscientific & Environmental Data (840.638 recursos)

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Datasets with PANGAEA technical keyword @ORFOISatBSiO2ss

Mostrando recursos 1 - 20 de 1.699

  1. High resolution study of sediment core GeoB3606-1

    Romero, Oscar E; Mollenhauer, Gesine; Schneider, Ralph R; Wefer, Gerold
    Based on a high-resolution analysis of the diatom signal and biogenic bulk components at site GeoB3606-1 (25°S, off Namibia), we describe rapid palaeoceanographic changes in the Benguela Upwelling System (BUS) from early MIS 3 through to the early Holocene (55 000 to 7 000 14C yr BP). Coastal upwelling strongly varied at 25°S from MIS 3 through to MIS 2. The abrupt decrease in the accumulation rate of biogenic silica and diatoms from MIS 3 into MIS 2 records rapid oceanographic changes in the BUS off Namibia. During MIS 3, leakage of excess H4SiO4 acid from the Southern Ocean into...

  2. High resolution study of sediment core GeoB3606-1

    Romero, Oscar E; Mollenhauer, Gesine; Schneider, Ralph R; Wefer, Gerold
    Based on a high-resolution analysis of the diatom signal and biogenic bulk components at site GeoB3606-1 (25°S, off Namibia), we describe rapid palaeoceanographic changes in the Benguela Upwelling System (BUS) from early MIS 3 through to the early Holocene (55 000 to 7 000 14C yr BP). Coastal upwelling strongly varied at 25°S from MIS 3 through to MIS 2. The abrupt decrease in the accumulation rate of biogenic silica and diatoms from MIS 3 into MIS 2 records rapid oceanographic changes in the BUS off Namibia. During MIS 3, leakage of excess H4SiO4 acid from the Southern Ocean into...

  3. Sedimentologic and magnetic data of sediment cores on the western slope of the Mid-Atlantic Ridge

    Franke, Christine; Hofmann, Daniela; von Dobeneck, Tilo
    The relative paleointensity (RPI) method assumes that the intensity of post depositional remanent magnetization (PDRM) depends exclusively on the magnetic field strength and the concentration of the magnetic carriers. Sedimentary remanence is regarded as an equilibrium state between aligning geomagnetic and randomizing interparticle forces. Just how strong these mechanical and electrostatic forces are, depends on many petrophysical factors related to mineralogy, particle size and shape of the matrix constituents. We therefore test the hypothesis that variations in sediment lithology modulate RPI records. For 90 selected Late Quaternary sediment samples from the subtropical and subantarctic South Atlantic Ocean a combined paleomagnetic...

  4. Sedimentologic and magnetic data of sediment cores on the western slope of the Mid-Atlantic Ridge

    Franke, Christine; Hofmann, Daniela; von Dobeneck, Tilo
    The relative paleointensity (RPI) method assumes that the intensity of post depositional remanent magnetization (PDRM) depends exclusively on the magnetic field strength and the concentration of the magnetic carriers. Sedimentary remanence is regarded as an equilibrium state between aligning geomagnetic and randomizing interparticle forces. Just how strong these mechanical and electrostatic forces are, depends on many petrophysical factors related to mineralogy, particle size and shape of the matrix constituents. We therefore test the hypothesis that variations in sediment lithology modulate RPI records. For 90 selected Late Quaternary sediment samples from the subtropical and subantarctic South Atlantic Ocean a combined paleomagnetic...

  5. Sedimentologic and magnetic data of sediment cores on the western slope of the Mid-Atlantic Ridge

    Franke, Christine; Hofmann, Daniela; von Dobeneck, Tilo
    The relative paleointensity (RPI) method assumes that the intensity of post depositional remanent magnetization (PDRM) depends exclusively on the magnetic field strength and the concentration of the magnetic carriers. Sedimentary remanence is regarded as an equilibrium state between aligning geomagnetic and randomizing interparticle forces. Just how strong these mechanical and electrostatic forces are, depends on many petrophysical factors related to mineralogy, particle size and shape of the matrix constituents. We therefore test the hypothesis that variations in sediment lithology modulate RPI records. For 90 selected Late Quaternary sediment samples from the subtropical and subantarctic South Atlantic Ocean a combined paleomagnetic...

  6. Sedimentology of the Okhotsk Sea

    Nürnberg, Dirk; Tiedemann, Ralf
    On the basis of two sedimentary records from the central Sea of Okhotsk, we reconstruct the closely coupled glacial/interglacial changes in terrigenous flux, marine productivity, and sea ice coverage over the past 1.1 Myr. The correspondance of our sedimentary records to the China loess grain size record (China loess particle timescale, CHILOPARTS) suggests that environmental changes in both the Sea of Okhotsk area and in SE Asia were closely related via the Siberian atmospheric high-pressure cell. During full glacial times our records point to a strong Siberian High causing northerly wind directions, the extension of the sea ice cover, and...

  7. Sedimentology of the Okhotsk Sea

    Nürnberg, Dirk; Tiedemann, Ralf
    On the basis of two sedimentary records from the central Sea of Okhotsk, we reconstruct the closely coupled glacial/interglacial changes in terrigenous flux, marine productivity, and sea ice coverage over the past 1.1 Myr. The correspondance of our sedimentary records to the China loess grain size record (China loess particle timescale, CHILOPARTS) suggests that environmental changes in both the Sea of Okhotsk area and in SE Asia were closely related via the Siberian atmospheric high-pressure cell. During full glacial times our records point to a strong Siberian High causing northerly wind directions, the extension of the sea ice cover, and...

  8. Geochemistry and paleontology of sediment core GeoB3359-3

    Romero, Oscar E; Kim, Jung-Hyun; Hebbeln, Dierk
    A geochemical and paleontological reconstruction of paleoproductivity, upwelling intensity and sea surface temperature (SST) off central Chile at 35°S (GeoB3359-3) reveals marked changes from the Last Glacial Maximum (LGM) through the Early Holocene. Surface-water productivity was determined by the interaction between the atmospheric (the Southern Westerlies) and oceanographic (the Antarctic Circumpolar Current, ACC) systems from the LGM through early Termination I (TI). The northward shift of the climate zones during the LGM brought the ACC, as the main macronutrient source, closer to the GeoB3359-3, SST lowered, and surface water productivity and accumulation rates of biogenic components enhanced. With the poleward...

  9. Geochemistry and paleontology of sediment core GeoB3359-3

    Romero, Oscar E; Kim, Jung-Hyun; Hebbeln, Dierk
    A geochemical and paleontological reconstruction of paleoproductivity, upwelling intensity and sea surface temperature (SST) off central Chile at 35°S (GeoB3359-3) reveals marked changes from the Last Glacial Maximum (LGM) through the Early Holocene. Surface-water productivity was determined by the interaction between the atmospheric (the Southern Westerlies) and oceanographic (the Antarctic Circumpolar Current, ACC) systems from the LGM through early Termination I (TI). The northward shift of the climate zones during the LGM brought the ACC, as the main macronutrient source, closer to the GeoB3359-3, SST lowered, and surface water productivity and accumulation rates of biogenic components enhanced. With the poleward...

  10. Biogenic sedimentation on the northern Norwegian continental shelf

    Knies, Jochen; Hald, Morten; Ebbesen, Hanne; Mann, Ute; Vogt, Christoph
    The relative proportions of marine organic carbon and biogenic carbonate in a high-resolution record from a glacial trough on the northern Norwegian continental shelf were used to decipher changes in biogenic sedimentation and paleoproductivity from the last deglaciation to the middle Holocene. Decadal-scale to century-scale oscillations in biogenic sedimentation and surface ocean productivity recorded in the Andfjorden sediments are synchronous with abrupt climate changes in open oceanic and atmospheric regimes of the high northern latitudes. Following several fluctuations during the Bølling-Allerød interstadial, the most dramatic drop in marine organic carbon and biogenic carbonate proportions occurred during the Younger Dryas. However,...

  11. Biogenic sedimentation on the northern Norwegian continental shelf

    Knies, Jochen; Hald, Morten; Ebbesen, Hanne; Mann, Ute; Vogt, Christoph
    The relative proportions of marine organic carbon and biogenic carbonate in a high-resolution record from a glacial trough on the northern Norwegian continental shelf were used to decipher changes in biogenic sedimentation and paleoproductivity from the last deglaciation to the middle Holocene. Decadal-scale to century-scale oscillations in biogenic sedimentation and surface ocean productivity recorded in the Andfjorden sediments are synchronous with abrupt climate changes in open oceanic and atmospheric regimes of the high northern latitudes. Following several fluctuations during the Bølling-Allerød interstadial, the most dramatic drop in marine organic carbon and biogenic carbonate proportions occurred during the Younger Dryas. However,...

  12. Biogenic sedimentation on the northern Norwegian continental shelf

    Knies, Jochen; Hald, Morten; Ebbesen, Hanne; Mann, Ute; Vogt, Christoph
    The relative proportions of marine organic carbon and biogenic carbonate in a high-resolution record from a glacial trough on the northern Norwegian continental shelf were used to decipher changes in biogenic sedimentation and paleoproductivity from the last deglaciation to the middle Holocene. Decadal-scale to century-scale oscillations in biogenic sedimentation and surface ocean productivity recorded in the Andfjorden sediments are synchronous with abrupt climate changes in open oceanic and atmospheric regimes of the high northern latitudes. Following several fluctuations during the Bølling-Allerød interstadial, the most dramatic drop in marine organic carbon and biogenic carbonate proportions occurred during the Younger Dryas. However,...

  13. Benthic and planktonic foraminifera of sediment core GIK17957-2

    Jian, Zhimin; Wang, Pinxian; Chen, Min-Te; Li, Bill; Zhao, Q H; Bühring, Christian; Laj, Carlo E; Lin, Hui-Ling; Pflaumann, Uwe; Bian, Y; Wang, Rujian; Cheng, Xinrong
    A detailed age model for core 17957-2 of the southern South China Sea was developed based on delta18O, coarse fraction, magnetostratigraphy, and biostratigraphy for the last 1500 kyr. The delta18O record has clear ~100-kyr cycles after the Mid-Pleistocene Revolution (MPR) at the entrance of marine isotopic stage (MIS) 22. Planktonic foraminifera responded to the MPR immediately, showing the increased sea surface temperature (SST) and dissolution after the MPR. Benthic foraminifera did not respond to it until the Brunhes/Matuyama boundary. Since the MPR, the depth of thermocline gradually became shallower until MISs 6-5. This major change within MISs 6-5 was also...

  14. Benthic and planktonic foraminifera of sediment core GIK17957-2

    Jian, Zhimin; Wang, Pinxian; Chen, Min-Te; Li, Bill; Zhao, Q H; Bühring, Christian; Laj, Carlo E; Lin, Hui-Ling; Pflaumann, Uwe; Bian, Y; Wang, Rujian; Cheng, Xinrong
    A detailed age model for core 17957-2 of the southern South China Sea was developed based on delta18O, coarse fraction, magnetostratigraphy, and biostratigraphy for the last 1500 kyr. The delta18O record has clear ~100-kyr cycles after the Mid-Pleistocene Revolution (MPR) at the entrance of marine isotopic stage (MIS) 22. Planktonic foraminifera responded to the MPR immediately, showing the increased sea surface temperature (SST) and dissolution after the MPR. Benthic foraminifera did not respond to it until the Brunhes/Matuyama boundary. Since the MPR, the depth of thermocline gradually became shallower until MISs 6-5. This major change within MISs 6-5 was also...

  15. Middle Miocene to recent sedimentological record of ODP sites 177-1088 and 177-1092

    Diekmann, Bernhard; Fälker, M; Kuhn, Gerhard
    During Leg 177 of the Ocean Drilling Program (ODP), well-preserved Middle Miocene to Pleistocene carbonate-rich sediment records were recovered on a north-south transect through the south-eastern Atlantic sector of the Southern Ocean at Site 1088 on the Agulhas Ridge and Site 1092 on Meteor Rise. Both sites were dominated by the deposition of calcareous nannofossil oozes through the Miocene, indicating low biological productivity in warm to temperate surface waters. A continuous increase in the proportions of foraminifera since the latest Miocene (6.5 Ma) points to enhanced nutrient supply, possibly related to the global 'biogenic bloom' event across the Miocene-Pliocene boundary....

  16. Middle Miocene to recent sedimentological record of ODP sites 177-1088 and 177-1092

    Diekmann, Bernhard; Fälker, M; Kuhn, Gerhard
    During Leg 177 of the Ocean Drilling Program (ODP), well-preserved Middle Miocene to Pleistocene carbonate-rich sediment records were recovered on a north-south transect through the south-eastern Atlantic sector of the Southern Ocean at Site 1088 on the Agulhas Ridge and Site 1092 on Meteor Rise. Both sites were dominated by the deposition of calcareous nannofossil oozes through the Miocene, indicating low biological productivity in warm to temperate surface waters. A continuous increase in the proportions of foraminifera since the latest Miocene (6.5 Ma) points to enhanced nutrient supply, possibly related to the global 'biogenic bloom' event across the Miocene-Pliocene boundary....

  17. Mineralogical and chemical investigation of biogenic siliceous Antarctic deep-ses sediments

    Bohrmann, Gerhard; Abelmann, Andrea; Gersonde, Rainer; Kuhn, Gerhard
    The formation of marine opal-CT nodules or layers as early diagenetic deposits has been documented only in Antarctic deep-sea sediments. In contrast, porcellanites and cherts in land sections and Deep Sea Drilling Project and Ocean Drilling Program drill sites are usually found in sediment sections of Miocene age and older. During R.V. Polarstem cruises ANT-IX/3 and 4, young porcellanites were recovered for the first time in contact with their host sediment in two cores from the Atlantic sector of the southern ocean. Chemical and mineralogical studies of these deposits and their surrounding sediments have increased knowledge about very early chert...

  18. Mineralogical and chemical investigation of biogenic siliceous Antarctic deep-ses sediments

    Bohrmann, Gerhard; Abelmann, Andrea; Gersonde, Rainer; Kuhn, Gerhard
    The formation of marine opal-CT nodules or layers as early diagenetic deposits has been documented only in Antarctic deep-sea sediments. In contrast, porcellanites and cherts in land sections and Deep Sea Drilling Project and Ocean Drilling Program drill sites are usually found in sediment sections of Miocene age and older. During R.V. Polarstem cruises ANT-IX/3 and 4, young porcellanites were recovered for the first time in contact with their host sediment in two cores from the Atlantic sector of the southern ocean. Chemical and mineralogical studies of these deposits and their surrounding sediments have increased knowledge about very early chert...

  19. Mineralogical and chemical investigation of biogenic siliceous Antarctic deep-ses sediments

    Bohrmann, Gerhard; Abelmann, Andrea; Gersonde, Rainer; Kuhn, Gerhard
    The formation of marine opal-CT nodules or layers as early diagenetic deposits has been documented only in Antarctic deep-sea sediments. In contrast, porcellanites and cherts in land sections and Deep Sea Drilling Project and Ocean Drilling Program drill sites are usually found in sediment sections of Miocene age and older. During R.V. Polarstem cruises ANT-IX/3 and 4, young porcellanites were recovered for the first time in contact with their host sediment in two cores from the Atlantic sector of the southern ocean. Chemical and mineralogical studies of these deposits and their surrounding sediments have increased knowledge about very early chert...

  20. Mineralogical and chemical investigation of biogenic siliceous Antarctic deep-ses sediments

    Bohrmann, Gerhard; Abelmann, Andrea; Gersonde, Rainer; Kuhn, Gerhard
    The formation of marine opal-CT nodules or layers as early diagenetic deposits has been documented only in Antarctic deep-sea sediments. In contrast, porcellanites and cherts in land sections and Deep Sea Drilling Project and Ocean Drilling Program drill sites are usually found in sediment sections of Miocene age and older. During R.V. Polarstem cruises ANT-IX/3 and 4, young porcellanites were recovered for the first time in contact with their host sediment in two cores from the Atlantic sector of the southern ocean. Chemical and mineralogical studies of these deposits and their surrounding sediments have increased knowledge about very early chert...

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