North Pacific Sediments

McCoy, Floyd W.; Sancetta, Constance

doi:10.1007/978-1-4613-2351-8_1

Cited by 9 publications

(4 citation statements)

References 119 publications

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“…Sharp peaks match the prominent powder diffraction lines of quartz, albite, apatite, halite, and zeolite (mostly phillipsite and clinoptilolite), and the broad maxima those from todorokite. Zeolite is a common Formation of todorokite from vernadite authigenic constituent of marine sediments (Halbach et al, 1975;Burns and Burns, 1978a;Usui and Ito, 1994), and is believed to form from the hydration of volcaniclastic material in seawater (Riley and Chester, 1971;Cronan, 1974;McCoy and Sancetta, 1985). Dehydrating the sample in vacuum decreased the d spacing of most zeolite peaks and the position and intensity of the maxima at 9.5-9.6 and 4.75-4.80 Å (Fig.…”

Section: Xrdmentioning

confidence: 92%

Formation of todorokite from vernadite in Ni-rich hemipelagic sediments

Bodeï

Manceau²,

Geoffroy³

et al. 2007

Geochimica et Cosmochimica Acta

154

155

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Section: Xrdmentioning

confidence: 92%

Formation of todorokite from vernadite in Ni-rich hemipelagic sediments

Bodeï

Manceau²,

Geoffroy³

et al. 2007

Geochimica et Cosmochimica Acta

154

155

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“…In this paper we present new insights into oceanographic variables controlling the distribution of deep‐sea sediments based on exploratory data analysis at each seafloor sample location and a probabilistic Gaussian process classifier that is trained to determine how surface ocean parameters and bathymetry relate to sediment lithology globally. We show that the parameters controlling the distribution of global seafloor sediments differ from the traditional view that sedimentation is primarily controlled by planktonic biological productivity [ McCoy and Sancetta , ]. Our analysis provides constraints for the oceanographic conditions under which deep‐sea sediments formed, at least for the Cenozoic, independent of taxonomic diversity of biogenic remains preserved within seafloor lithologies.…”

Section: Introductionmentioning

confidence: 99%

Controls on the distribution of deep‐sea sediments

Dutkiewicz

O’Callaghan

Müller

2016

Geochem Geophys Geosyst

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Deep‐sea sediments represent the largest geological deposit on Earth and provide a record of our planet's response to conditions at the sea surface from where the bulk of material originates. We use a machine learning method to analyze how the distribution of 14,400 deep‐sea sediment sample lithologies is connected to bathymetry and surface oceanographic parameters. Our probabilistic Gaussian process classifier shows that the geographic occurrence of five major lithologies in the world's ocean can be predicted using just three parameters. Sea‐surface salinity and temperature provide a major control for the growth and composition of plankton and specific ranges are also associated with the influx of non‐aerosol terrigenous material into the ocean, while bathymetry is an important parameter for discriminating the occurrence of calcareous sediment, clay and coarse lithogenous sediment from each other. We find that calcareous and siliceous oozes are not linked to high surface productivity. Diatom and radiolarian oozes are associated with low salinities at the surface but with discrete ranges of temperatures, reflecting the diversity of planktonic species in different climatic zones. Biosiliceous sediments cannot be used to infer paleodepth, but are good indicators of paleotemperature and paleosalinity. Our analysis provides a new framework for constraining paleosurface ocean environments from the geological record of deep‐sea sediments. It shows that small shifts in salinity and temperature significantly affect the lithology of seafloor sediment. As deep‐sea sediments represent the largest carbon sink on Earth these shifts need to be considered in the context of global ocean warming.

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“…Major obstacles to obtaining further records are the vast turbidite sequences found in the far northeastern Pacific and the scarcity of carbonates due to the relatively shallow carbonate compensation depth (CCD). Both factors make the pursuit of stratigraphic and paleoenvironmental work in the Subarctic Pacific difficult (e.g., McCoy and Sancetta [1985]). However, the North Pacific contains more than 25% of the world ocean volume and, in the absence of local deepwater formation, is a major carbon reservoir [Kroopnick, 1985].…”

mentioning

confidence: 99%

Water Mass Conversion in the Glacial Subarctic Pacific (54°N, 148°W): Physical Constraints and the Benthic‐Planktonic Stable Isotope Record

Zahn¹,

Pedersen²,

Bornhold³

et al. 1991

Paleoceanography

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Benthic (Uvigerina spp., Cibicidoides spp., Gyroidinoides spp.) and planktonic (N. pachyderma sinistral, G. bulloides) stable isotope records from three core sites in the central Gulf of Alaska are used to infer mixed‐layer and deepwater properties of the late glacial Subarctic Pacific. Glacial‐interglacial amplitudes of the planktonic δ18O records are 1.1–1.3‰, less than half the amplitude observed at core sites at similar latitudes in the North Atlantic; these data imply that a strong, negative δw anomaly existed in the glacial Subarctic mixed layer during the summer, which points to a much stronger low‐salinity anomaly than exists today. If true, the upper water column in the North Pacific would have been statically more stable than today, thus suppressing convection even more efficiently. This scenario is further supported by vertical (i.e., planktic versus benthic) δ18O and δ13C gradients of >1‰, which suggest that a thermohaline link between Pacific deep waters and the Subarctic Pacific mixed layer did not exist during the late glacial. Epibenthic δ13C in the Subarctic Pacific is more negative than at tropical‐subtropical Pacific sites but similar to that recorded at Southern Ocean sites, suggesting ventilation of the deep central Pacific from mid‐latitude sources, e.g., from the Sea of Japan and Sea of Okhotsk. Still, convection to intermediate depths could have occurred in the Subarctic during the winter months when heat loss to the atmosphere, sea ice formation, and wind‐driven upwelling of saline deep waters would have been most intense. This would be beyond the grasp of our planktonic records which only document mixed‐layer temperature‐salinity fields extant during the warmer seasons. Also we do not have benthic isotope records from true intermediate water depths of the Subarctic Pacific.

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North Pacific Sediments

Cited by 9 publications

References 119 publications

Formation of todorokite from vernadite in Ni-rich hemipelagic sediments

Formation of todorokite from vernadite in Ni-rich hemipelagic sediments

Controls on the distribution of deep‐sea sediments

Water Mass Conversion in the Glacial Subarctic Pacific (54°N, 148°W): Physical Constraints and the Benthic‐Planktonic Stable Isotope Record

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