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Thursday, July 16, 2020 | History

2 edition of Interactions of biogenic opal, sediment, and seawater in the central equatorial Pacific. found in the catalog.

Interactions of biogenic opal, sediment, and seawater in the central equatorial Pacific.

David C. Hurd

Interactions of biogenic opal, sediment, and seawater in the central equatorial Pacific.

by David C. Hurd

  • 324 Want to read
  • 34 Currently reading

Published by Hawaii Institute of Geophysics, University of Hawaii] in [Honolulu .
Written in English

    Places:
  • Pacific Ocean.
    • Subjects:
    • Opals.,
    • Silica.,
    • Chemical oceanography -- Pacific Ocean.

    • Edition Notes

      SeriesUniversity of Hawaii. Hawaii Institute of Geophysics. HIG-72-22, HIG (Series) ;, 72-22.
      ContributionsUnited States. Office of Naval Research.
      Classifications
      LC ClassificationsQE500 .H35 no. 72-22, GC116 .H35 no. 72-22
      The Physical Object
      Paginationvii, 81 p.
      Number of Pages81
      ID Numbers
      Open LibraryOL5026809M
      LC Control Number73621359

      The timing and mechanisms of the eastern equatorial Pacific (EEP) cold tongue development, a salient feature of the tropical ocean, are intensely debated on geological time scales. Here, we reconstruct cold tongue evolution over the past 8 million years by computing changes in temperature gradient between the cold tongue and eastern Pacific warm pool.   Abstract Analysis of physical properties measured on cores and on discrete samples collected by the Ocean Drilling Programme (ODP) Leg on the Pacific margin of the Antarctic Peninsula reveals anomalous down‐hole curves of porosity, density, water content, and P‐wave velocity. These indicate an overall trend of increasing porosity with depth and suggest .

        The sediment trap study carried out for the measurement of biogenic fluxes in the Northern Indian Ocean found predominance of opal fluxes at western Arabian Sea and the Bay of Bengal. But the eastern Arabian Sea, the southern Bay of Bengal (SBBT), and the equatorial Indian Ocean (EIOT) traps are dominated by carbonate fluxes (Ramaswamy and.   Here we present a new sediment core from the Eastern Equatorial Pacific (EEP) Ocean spanning the last , years and reconstruct high-resolution Th-derived fluxes of Th and excess.

      These large-scale patterns cannot be easily explained by postdepositional sediment redistribution (Dezileau et al., ) and contradict the widely held view, based on hydrographic and sediment trap data, that biogenic opal accumulation in the Southern Ocean is linked to high surface productivity (e.g., Nelson et al., ; Pondaven et al., ). Silicon is a keystone nutrient in the ocean for understanding climate change because of the importance of Southern Ocean diatoms in taking up CO 2 from the surface ocean‐atmosph.


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Interactions of biogenic opal, sediment, and seawater in the central equatorial Pacific by David C. Hurd Download PDF EPUB FB2

U.i Interactions of biogenic opal, sediment and seawater in the Central Equatorial Pacific Although HABT () claims an overall silica loss from basalts during the first 7 million years contact with seawater of x 10~9 g Si/g basalt/yr, the SiOg/Algt^ ratios from his Fig.

2 show no change whatsoever in this time by: Get this from a library. Interactions of biogenic opal, sediment, and seawater in the central equatorial Pacific. [David C Hurd; United States. Office of Naval Research.]. The solution rate of biogenic opal in near-surface sediments in the Central Equatorial Pacific is three to eight orders of magnitude lower than similar acid-cleaned samples.

Iron, magnesium and calcium aluminosilicates may be the minerals which are forming on the surface of the opal and reducing its solution rate. The scale height of the system studied Cited by: Hurd, D.C. Interactions of biogenic opal, sediment and seawater in the central equatorial Pacific Geochimica et Cosmochimica Acta 37 Hurd, D.C.

Theyer, F. Changes in the physical and chemical properties of biogenic silica from the Central Equatorial Pacific. Part by: Sediment traps deployed at two sites in the equatorial Pacific during and following the ‐ El Niño southern oscillation (ENSO) demonstrate the biological effects of this event.

Biogenic Cited by:   HiiRD D. () Interactions of biogenic opal, sediment and seawater in the central equatorial Pacific. Ph.D. dis- sertation, Honolulu, University of Hawaii, 81 pp. JONES J. and SEGNIT E. () The nature of opal I. Hurd DC () Interactions of biogenic opal, sediment and seawater in the central equatorial Pacific.

Geochim Cosmochim Acta – CrossRef Google Scholar Isaacs CM () Influence of rock composition on kinetics of silica phase changes in the Monterey formation, Santa Barbara area, California.

Hurd DC () Interactions of biogenic opal, Sediment and seawater in the Central Equatorial Pacific. Geochimica Cosmochimica Acta – Google Scholar; Heath GR () Dissolved silica and deep sea Sediments.

Society of Economic Paleontologists and Mineralogists spec. publ. –   Hul~ D. () Factors affecting solution rate of biogenic opal in seawater. Earth and Planetary Science Letters, 15, HusD D. () Interactions of biogenous opal, sediment and seawater in the central equatorial Pacific.

Geochimica et Cosmochimica Acta, 37,   Biogenic silica (opal) was determined by the method of Hurd (), in which biogenic silica was leached with 5% Na2C03 solution at 86 C for 5 h. The contents of OM and CaC03 were estimated by the method of Noriki and Tsunogai (), and aluminosilicate (clay) content was given by (OM +opal+CaC03) in weight per cent.

—: Interactions of biogenic opal, sediment and seawater in the Central Equatorial Pacific. Geochim. cosmochim. A – () Google Scholar.

Iler, R.K.: The colloidal chemistry of silica and silicates, pp. New York: Cornell University Press Google Scholar. Hurd, D.

Interactions of biogenic opal, sediment and seawater in the Central Equatorial Pacific. Geochim. Cosmochim. A – (). Physical, chemical and geological properties of sediments from the central equatorial Pacific, supplement to: Hurd, David C (): Interactions of biogenic opal, sediment and seawater in.

The pore water concentrations of dissolved silica in sediment cores from the continental slope offshore from Cape Hatteras, North Carolina, varied from to almost μ,M with depth in the top 40 cm of sediment.

Sediment cores from to m depth had very similar profiles of dissolved silica in their pore waters, even though these cores came from. The orbital-scale variations in biogenic CaCO3 and opal abundance in two piston cores collected in the central equatorial Pacific (core PC from a.

Other biogenic components are nannofossils, fragments of planktic and benthic foraminifers, fish debris, fragments of worm tubes, and fecal pellets. Authigenic minerals are important sediment builders in the equatorial North Pacific. Authigenic Fe-rich smectite, on the average, makes up 10% of the sediment.

In the central equatorial Pacific, settling particles collected with sediment traps have Al/Ti values greater than those of a typical crustal source. The Al/Ti values of the sediment trap material are not well correlated with either the flux of organic carbon or with total particle mass, suggesting that this ratio cannot be used as a simple.

The chemical and isotopic compositions of oceanic biogenic and authigenic minerals contain invaluable information on the evolution of seawater, hence on the history of interaction between tectonics, climate, ocean circulation, and the evolution of life. Important advances and greater understanding of (a) key minor and trace element cycles with various residence times, (b).

We examined the flux of Al to sediment accumulating beneath the zone of elevated productivity in the central equatorial Pacific Ocean, along a surface sediment transect at. [1] We have measured Th‐normalized opal fluxes in several cores from the eastern equatorial Pacific (EEP) to test the validity of the “silica leakage” hypothesis, which purports that redistribution of silicic acid from the Southern Ocean to the low latitudes was responsible for a significant portion of the reduction in atmospheric carbon dioxide (CO 2) during the last glacial.

Mechanisms that control the preservation of organic carbon in the ocean are the key to interpreting the paleoceanographic carbon signal.

This process is investigated here utilizing published data from sediment trap experiments in a model that couples organic carbon and oxygen reactions in marine sediments.Sixteen deep‐sea cores from the central equatorial Pacific are used to reconstruct a continuous ,‐year (‐kyr) record of bathymetric variations in carbonate preservation as measured by calcium carbonate (CaCO 3) depth of the sedimentary lysocline has fluctuated markedly in conjunction with late Pleistocene climate cycles while the carbonate critical depth .The com-monly used 2-M Na 2 CO 3 leach is inadequate for the rapid digestion of biogenic opal for radiolarians (e.g., Leg sediments), but a 2-M .