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2 edition of Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic found in the catalog.

Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic

Margaret Leinen

Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic

by Margaret Leinen

  • 14 Want to read
  • 19 Currently reading

Published .
Written in English

    Subjects:
  • Silica -- Pacific Ocean.

  • Edition Notes

    Statementby Margaret Leinen.
    The Physical Object
    Pagination[11], 136 leaves, bound :
    Number of Pages136
    ID Numbers
    Open LibraryOL15519718M

    CENOZOIC BIOGENIC SILICA SEDIMENTATION IN THE ANTARCTIC OCEAN Pamphlet – January 1, by Nancy Ann Brewster (Author) See all formats and editions Hide other formats and editions. Price New from Used from Pamphlet Author: Nancy Ann Brewster. 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 °W as well as downcore for a kyr record at °N, °W. Across the surface transect, a pronounced, broadly equatorially symmetric increase in Al accumulation is observed, relative to Ti, with .

    Ocean. Productivity is low and diatoms are rare in the Holocene sed-iments capping the rise (Lisitzin, ; Curry, Shackleton, Richter, et al., ). Biogenic silica accumulation in the Ceara Rise region, however, has been significant during two periods of the Cenozoic: the early Oligocene and early Miocene (Fig. 2). Biogenic silica accumulation in the central equatorial Pacific and its implications for Cenozoic paleoceanography - summary. Geological Society of America Bulletin. /()co;2 Abstract Website.

    Biogenic sediments are the skeletal remains of either plant or animal marine species. The hard skeletal structures of marine organisms are important constituents of the deep ocean sediment and many layers of the deep ocean floor are almost entirely composed of calcareous and siliceous skeletal remains.   Leinin M. Biogenic silica accumulation in the central equatorial Pacific and its implications for Cenozoic paleoceanography. Geol Soc Am Bull. ; –


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Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic by Margaret Leinen Download PDF EPUB FB2

Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic Public Deposited Maps of these accumulation rates for time intervals during the Cenozoic show that opal accumulation was highest near the equator or paleoequator during the last 50 m.y.

Superimposed on this pattern are fluctuations in the rate of opal Cited by: 3. During this time, the central equatorial Pacific Ocean has become one of the most intensively studied geologic provinces in the world ocean.

This area lies beneath the biologically productive equatorial current system which supplies great quantities of calcium carbonate and amorphous silica (opal) to the sediment in the form of skeletal by: Biogenic silica sedimentation in the central equatorial Pacific during the Cenozoic.

The procedure was tested against the X-ray\ud diffraction method for determining opal in deep-sea sediments\ud The biogenic silica content of Cenozoic sediments from 20 Deep\ud Sea Drilling Project sites in the central equatorial Pacific was. Biogenic silica (bSi), also referred to as opal, biogenic opal, or amorphous opaline silica, forms one of the most widespread biogenic example, microscopic particles of silica called phytoliths can be found in grasses and other plants.

Silica is an amorphous metal oxide formed by complex inorganic polymerization processes. This is opposed to the other major biogenic. Quaternary abyssal benthic foraminifera were compared in terms of multi-dimensional scaling (MDS) in the Central Equatorial Pacific Ocean.

• In core PC, located closer to the equator, MDS axis 1 scores are negatively correlated to the biogenic opal mass accumulation rates (MAR) after by: 1.

Cenozoic biogenic silica sedimentation in the Antarctic Ocean, based on two deep sea drilling project sites silica supply has been transferred to the Antarctic at the expense of other productive oceanic regions such as the Central Equatorial Pacific.

In the Neogene, the preservation or dissolution of calcium carbonate is influenced by the. The equatorial Pacific is an important part of the global carbon cycle and has been affected by climate change through the Cenozoic (65 Ma to present).

We present a Miocene ( Ma) biogenic sediment record from Deep Sea Drilling Project (DSDP) Site and show that a CaCO 3 minimum at 17 Ma was caused by elevated CaCO 3 > dissolution. A synthesis of Eocene biogenic silica accumulation rates in the equatorial zone of the Pacific shows several relatively broad maxima spaced a few million years apart and extending from the.

Leinen, M., Biogenic Silica Accumulation in the Central Equatorial Pacific and Its Impications for Cenozoic Paleoceanography,Geol. Soc. Bull.,vol. 90, pp. – Google Scholar Levitan, M.A., Biogenic Silica As a Source of Material for the Formation of Cherts in Pacific Sediments, Extended Abstracts of PhD (Geol.-Miner.).

Due to abundant biogenic calcite (CaCO 3) and high continuous sedimentation rates, International Ocean Drilling Program (IODP) Site U, in the eastern equatorial Pacific. 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 partic. Among the first uses of silica in biology came from flora that littered the Earth. At that time 23 million years ago, during the Neogene period, silica was abundant in the soil from the diagenesis of many sources of biogenic lly, plants are able to absorb elemental Si in the form of silicic acid and via several steps of condensation in the processing of silicic acid such as the.

[1] Using a three‐dimensional physical‐biogeochemical model, we have investigated the modeled responses of diatom productivity and biogenic silica export to iron enrichment in the equatorial Pacific, and compared the model simulation with in situ (IronEx II) iron fertilization results.

In the eastern equatorial Pacific, an area ofkm 2 was enhanced with iron by changing the. The Pacific, as the world’s largest ocean, is intricately involved in the prominent changes in the global carbon cycle and climate system that took place during the Cenozoic equatorial.

Cenozoic biogenic silica sedimentation in the Antarctic Ocean, silica supply has been transferred to the Antarctic at the expense of other productive oceanic regions such as the Central Equatorial Pacific. In the Neogene, the preservation or dissolution of calcium carbonate is influenced by the rate of upwelling south of the Polar Front.

These results suggest that the high primary productivity in the eastern to central equatorial Pacific has been maintained throughout the Cenozoic. The high-IC6 samples correspond to sediments of 35–40 Ma at DSDP Site 45 in the central North Pacific and those of ~65 Ma at DSDP Site off southwestern India (Fig.

3e). Ridge (Site ). Biogenic silica-rich facies are rare and mainly located near the top of the lowest latitude sites. Descriptions of the major sedimentary facies lead to discussions and speculations about depositional conditions and hence about the Cenozoic paleoenvironment in the central western Indian Ocean.

Important changes in. A detailed reconstruction of the calcium carbonate compensation depth—at which calcium carbonate is dissolved—in the equatorial Pacific Ocean over. In the middle Holocene, productivity increased significantly during yr B.P., but little biogenic silica accumulated in sediments because the dominant primary producer was not diatom flora and because of the relatively higher productivity caused.

More than 90% of the sediments in the equatorial Pacific are biogenic in origin, so sedimentation rates are a semiquantitative proxy of paleoproductivity in the region. Moore et al. () used these ideas to study the Cenozoic evolution of Pacific equatorial zone.

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 .Previous | Next.

doi/ References. Abels, H.A., Hilgen, F.J., Krijgsman, W., Kruk, R.W., Raffi, I., Turco, E., and Zachariasse, W.J., Changes in climate during the Cenozoic (65 Ma to present) have impacted the carbon cycle, and it is important to Bio-SiO 2 Biogenic Silica C org Organic Carbon Deep Sea Drilling Project a series of 5 sites were drilled in the Central equatorial Pacific.

DSDP Site was studied for this thesis to augment the datasets published in.