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Registros recuperados: 7
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A paleomagnetic approach toward refining Holocene radiocarbon-based chronologies: Paleoceanographic records from the north Iceland (MD99-2269) and east Greenland (MD99-2322) margins ArchiMer
Stoner, Joseph S.; Jennings, Anne; Kristjansdottir, Greta B.; Dunhill, Gita; Andrews, John T.; Hardardottir, Jorunn.
We report the intercalibration of paleomagnetic secular variation (PSV) and radiocarbon dates of two expanded postglacial sediment cores from geographically proximal, but oceanographically and sedimentologically contrasting settings. The objective is to improve relative correlation and chronology over what can be achieved with either method alone. Core MD99-2269 was taken from the Hunafloaall Trough on the north Iceland shelf. Core MD99-2322 was collected from the Kangerlussuaq Trough on the east Greenland margin. Both cores are well dated, with 27 and 20 accelerator mass spectrometry (14)C dates for cores 2269 and 2322, respectively. Paleomagnetic measurements made on u channel samples document a strong, stable, single-component magnetization. The...
Tipo: Text Palavras-chave: Holocene; Paleomagnetic secular variation; Radiocarbon dating.
Ano: 2007 URL: https://archimer.ifremer.fr/doc/00233/34436/32934.pdf
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Evolution of the northeast Labrador Sea during the last interglaciation ArchiMer
Winsor, Kelsey; Carlson, Anders E.; Klinkhammer, Gary P.; Stoner, Joseph S.; Hatfield, Robert G..
Boreal summer insolation during the last interglaciation (LIG) generally warmed the subpolar to polar Northern Hemisphere more than during the early Holocene, yet regional climate variations between the two periods remain. We investigate northeast Labrador Sea subsurface temperature and hydrography across terminations (T) I and II and during the LIG to assess the impact of two different magnitudes of boreal summer insolation increase on the northeast Labrador Sea. We use Mg/Ca ratios in Neogloboquadrina pachyderma (sinistral) as a proxy of calcification temperature to document changes in subsurface temperatures over Eirik Drift. Our corresponding record of delta O-18 of seawater documents changes in water mass salinity. Mg/Ca calcification temperatures...
Tipo: Text Palavras-chave: Neogloboquadrina pachyderma (sinistral); Labrador Sea; Mg/Ca; Deglaciations; Interglaciations; Subpolar gyre.
Ano: 2012 URL: https://archimer.ifremer.fr/doc/00265/37604/36840.pdf
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Interglacial responses of the southern Greenland ice sheet over the last 430,000 years determined using particle-size specific magnetic and isotopic tracers ArchiMer
Hatfield, Robert G.; Reyes, Alberto V.; Stoner, Joseph S.; Carlson, Anders E.; Beard, Brian L.; Winsor, Kelsey; Welke, Bethany.
The past behavior of the Greenland ice sheet can provide important insight into climatic thresholds that may initiate and drive major ice-sheet retreat. Particle-size-specific magnetic and Sr–Nd–Pb isotope records from Eirik Ridge sediments south of Greenland track southern Greenland ice sheet (sGIS) erosional signatures over the past ∼430 ka by discriminating changes in sediment source and transport over the Eirik Ridge. Ground-truthed magnetic and isotopic compositions of subglacial silt from south Greenland's Precambrian bedrock terranes constrain independent magnetic and isotopic estimates of Eirik Ridge silt provenance, which in turn indicate that the southern Greenland ice sheet (sGIS) retreated within its present margin during three of the four...
Tipo: Text Palavras-chave: South Greenland ice sheet; Sediment tracing; Radiogenic isotopes; Magnetic properties; Quaternary climate change; Sea-level rise.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00353/46384/46007.pdf
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Paleointensity-assisted chronostratigraphy of detrital layers on the Eirik Drift (North Atlantic) since marine isotope stage 11 ArchiMer
Evans, Helen F.; Channell, James E. T.; Stoner, Joseph S.; Hillaire-marcel, Claude; Wright, James D.; Neitzke, Lauren C.; Mountain, Gregory S..
Four piston cores collected in 1999 and 2002 from the Eirik Drift (southern Labrador Sea, off SE Greenland) provide paleomagnetic, environmental magnetic, and oxygen isotope records back to marine isotope stage 11. Age models for the cores are based on a combination of planktonic oxygen isotope data, relative geomagnetic paleointensity proxies, and the identification of geomagnetic excursions (Laschamp and Iceland Basin). Environmental magnetic data delineate two distinct detrital signals, interpreted to reflect the behavior of the surrounding ice sheets (Greenland and Laurentide) to orbital-and millennial-scale climate forcing. Broad decimeter-scale intervals of increased magnetic concentration and grain size occur during the early part of interglacial...
Tipo: Text Palavras-chave: Paleointensity.
Ano: 2007 URL: https://archimer.ifremer.fr/doc/00235/34625/32978.pdf
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Particle size specific magnetic properties across the Norwegian-Greenland Seas: Insights into the influence of sediment source and texture on bulk magnetic records ArchiMer
Hatfield, Robert G.; Wheeler, Benjamin H.; Reilly, Brendan T.; Stoner, Joseph S.; Housen, Bernard A..
We make fundamental observations of the particle size variability of magnetic properties from 71 core tops that span the southern Greenland and Norwegian Seas. These data provide the first detailed regional characterization of how bulk magnetic properties vary with sediment texture, sediment source, and sediment transport. Magnetic susceptibility (MS) and hysteresis parameters were measured on the bulk sediment and the five constituent sediment particle size fractions (clay, fine, medium, and coarse silt, and sand). The median MS value of the medium silt size fraction is ~3‐5 times higher than that of the sand and clay size fractions and results in a strong sensitivity of bulk MS to sediment texture. Hysteresis properties of the clay size fraction are...
Tipo: Text Palavras-chave: Northern Basaltic Province; Magnetic susceptibility; Nordic Seas; Magnetic grain size; Sediment source; Sediment transport.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00478/58998/61614.pdf
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Productivity and sedimentary delta N-15 variability for the last 17,000 years along the northern Gulf of Alaska continental slope ArchiMer
Addison, Jason A.; Finney, Bruce P.; Dean, Walter E.; Davies, Maureen H.; Mix, Alan C.; Stoner, Joseph S.; Jaeger, John M..
Biogenic opal, organic carbon, organic matter stable isotope, and trace metal data from a well-dated, high-resolution jumbo piston core (EW0408-85JC; 59 degrees 33.3'N, 144 degrees 9.21'W, 682 m water depth) recovered from the northern Gulf of Alaska continental slope reveal changes in productivity and nutrient utilization over the last 17,000 years. Maximum values of opal concentration (similar to 10%) occur during the deglacial Bolling-Allerod (B-A) interval and earliest Holocene (11.2 to 10.8 cal ka BP), moderate values (similar to 6%) occur during the Younger Dryas (13.0 to 11.2 cal ka BP) and Holocene, and minimum values (similar to 3.5%) occur during the Late Glacial Interval (LGI). When converted to opal mass accumulation rates, the highest values...
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Ano: 2012 URL: https://archimer.ifremer.fr/doc/00266/37680/36920.pdf
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The influence of high-latitude flux lobes on the Holocene paleomagnetic record of IODP Site U1305 and the northern North Atlantic ArchiMer
Stoner, Joseph S.; Channell, James E. T.; Mazaud, Alain; Strano, Sarah E.; Xuan, Chuang.
Paleomagnetic analysis and radiocarbon dating of an expanded Holocene deep-sea sediment sequence recovered by Integrated Ocean Drilling Program (IODP) Expedition 303 from Labrador Sea Site U1305 (Lat.: 57 degrees 28.5 N, Long.: 48 degrees 31.8 W, water depth 3459 m) provides insights into mechanisms that drive both paleomagnetic secular variation (PSV) and magnetization acquisition in deep-sea sediments. Seventeen radiocarbon dates on planktonic foraminifera define postglacial (ca. 8 ka) sedimentation rates as ranging from 35 to > 90 cm/kyr. Alternating field (AF) demagnetization of u-channel samples show that these homogeneous sediments preserve a strong, stable, and consistently well-defined component magnetization. Normalized remanence records pass...
Tipo: Text Palavras-chave: Paleomagnetism; North Atlantic; Paleointensity.
Ano: 2013 URL: https://archimer.ifremer.fr/doc/00264/37480/36500.pdf
Registros recuperados: 7
Primeira ... 1 ... Última
 

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