Diatom stratigraphy of the late Pleistocene (Brunhes) subarctic Pacific

Sancetta, Constance; Silvestri, ShayMaria

doi:10.1016/0377-8398(84)90016-1

Cited by 44 publications

(18 citation statements)

References 12 publications

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“…Sedimentary records have demonstrated an intimate link between past changes in global climate and the biogeochemical dynamics of the subarctic Pacific [e.g., Haug et al , 1999; Sancetta and Silvestri , 1984]. Perhaps most notably, the accumulations of biogenic opal and Ba in subarctic sediments were significantly lower during globally cold periods, and show remarkable correlations with Antarctic temperatures on glacial‐interglacial timescales [ Jaccard et al , 2005; Kienast et al , 2004; Narita et al , 2002; Nürnberg and Tiedemann , 2004; Shigemitsu et al , 2007].…”

Section: Introductionmentioning

confidence: 99%

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

et al. 2008

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The open subarctic Pacific is, at present, a high nitrate low chlorophyll (HNLC) region, where nitrate is perennially abundant at the surface. Theoretically, the HNLC status of this region is subject to modification by ocean circulation and/or micronutrient supply, with implications for the effectiveness of the biological pump and hence carbon sequestration in the ocean interior. Records of biogenic detritus in sediments from throughout the subarctic Pacific indicate that export production was generally lower during glacial maxima, while nitrogen isotope measurements from the Bering Sea have shown that nitrate consumption there was more complete during the last glacial period than it is today. Here, nitrogen isotopic analyses of bulk sediments (δ15Nbulk) from three deep water sites in the open subarctic Pacific are evaluated in terms of regional nitrate isotopic composition and local relative nitrate utilization. The eastern subarctic Pacific δ15Nbulk record bears great similarity to δ15Nbulk records from the western margin of North America over the last glacial cycle, suggesting that variability in the isotopic composition of subeuphotic zone nitrate, the growth substrate, is reasonably coherent throughout the northeast Pacific and dominates at these sites. However, the two western subarctic Pacific records, which lie at the heart of the HNLC region, display a different pattern, implying that significant changes in local relative nitrate utilization overlie the regional background variability. After a novel correction intended to remove the background signal associated with denitrification in the eastern tropical North Pacific, these nitrate utilization records are correlated with a benthic oxygen isotope stack reflecting global deep ocean temperature and ice volume (r2 = 0.65). The correlation implies a strong link between global climate and subarctic Pacific nitrate utilization, with nearly complete nitrate consumption during glacial periods when export production was low.

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Section: Introductionmentioning

confidence: 99%

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

et al. 2008

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“…Following this interval is a mode change to less variation in wind intensity in the younger portion of the record compared to the older part, which extends back to 950 ka. In the siliceous plankton records[Sancetta and Silvestri, 1984], the mid-Brunhes climatic event is a fundamental change in environmental conditions based on changes in the relative abundance of flora, changes in floral abundance patterns, and the disappearance or extinction of two diatom species. If CaCO 3 preservation in the central equatorial Pacific is predominantly a record of deepwater geochemical and hydrodynamic change, rather than a reflection of local variations in surface input of calcite and organic carbon, then the temporal coincidence of the preservation pattern with changes in eolian and siliceous records suggests that the mid-Brunhes climate event affected the circulation of deep waters as well as surface waters and the atmosphere.…”

mentioning

confidence: 99%

Climatic change and CaCO₃ preservation: An 800,000 year bathymetric Reconstruction from the central equatorial Pacific Ocean

Farrell¹,

Prell²

1989

Paleoceanography

389

272

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Sixteen deep‐sea cores from the central equatorial Pacific are used to reconstruct a continuous 800,000‐year (800‐kyr) record of bathymetric variations in carbonate preservation as measured by calcium carbonate (CaCO3) content. The depth of the sedimentary lysocline has fluctuated markedly in conjunction with late Pleistocene climate cycles while the carbonate critical depth (CCrD), which is the water depth where the sediments contain 10% CaCO3, has remained relatively constant. As a result, the depth of the lysocline controls the bathymetric position and thickness of the CaCO3 transition zone, defined as the depth from the lysocline to the CCrD. Modern and interglacial‐aged sediments show poor CaCO3 preservation and thick CaCO3 transition zones. Glacial‐aged sediments show good preservation and deep, thin zones due to the deepening of the lysocline. Detailed comparison of the CaCO3 preservation and oxygen isotope records from the central equatorial Pacific confirms the observation that preservation maxima and minima tend to occur during the latter half of glacial and interglacial stages and on climate transitions rather than during the middle of climatic stages. During the nine major glacial stages of the last 800 kyr, the lysocline deepened by at least 400 to 800 m. This deepening indicates an increase in the abyssal carbonate ion concentration ([CO3=]) and a depression of the calcite saturation horizon best explained by the deeper presence of a more carbonate‐saturated water mass. The bottom of the transition zone has remained at a relatively constant depth during the Brunhes Chron, indicating a balance between CaCO3 sedimentation and dissolution in the deepest waters of the central equatorial Pacific.

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“…Finally, it should be noted that the mid Pleistocene (between 1.25 and 0.6 Ma) revolution was characterized by the onset of severe climatic conditions, when the Subarctic Front repeatedly shifted southward in the North Pacific [37], and the main hydrologic fronts in the Southern Ocean shifted up to 7° latitude north dur ing glacials [38]. At the same time, the orbitally forced climatic fluctuations at 41 kyr cycles were superseded by a 100 kyr rhythm of climate changes [39].…”

Section: Discussionmentioning

confidence: 99%

Facies structure and quantitative parameters of pleistocene pelagic sedimentation in the Indian Ocean

2014

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We also applied Strakhov's method of comparative lithology [3] and utilized the map of recent sediment distribution in the Indian Ocean as a reference [7]. Sed iment thickness was determined for each Pleistocene section using all available data, using the sedimentation rates provided by Lisitsyn [8] as a reference.This study is based on data collected during deep sea drilling in the pelagic zones of the Indian Ocean (DSDP Legs 22 28 and ODP Legs 115 121). In addi tion, we used evidence obtained by the IMAGES project [9], as well as extensive published data on the Pleistocene sediments and Quaternary paleoceanogra phy ([10-12] and others).The results were two lithofacies maps of the Indian Ocean, which were created as azimuthal equal area equatorial projections at a scale of 1 : 35000000 for the Eopleistocene (Q 1 , within the 1.8-0.8 Ma interval) (Fig. 1) and the Neopleistocene (Q 2 + 3 , 0.8-0.01 Ma) (Fig. 2) (the boundaries of the subdivisions are after [13]). The boundary between the Eopleistocene and Neopleistocene was chosen to coincide with the Matuyama-Brunhes reversal [13]. The choice of these stratigraphic subdivisions was based on the global cool ing trend and more pronounced glacial-interglacial cli mate variations in the Neopleistocene relative to the Eopleistocene [14].The maps show the distributions of the main facies (abyssal, pelagic, and hemipelagic) defined by the boundaries between the bottom sedimentary environ ments, the locations of a series of submarine intraplate rises at depths of commonly less than 3 km, areas of mid oceanic ridge basaltic volcanism of the respective age, and areas of non deposition. The area, thickness, Abstract-We compiled lithofacies maps for the early and middle-late Pleistocene (Eopleistocene and Neo pleistocene, respectively) pelagic sedimentation of the Indian Ocean and a database for sediment thicknesses in the respective stratigraphic subdivisions. Using these data, we calculated areas, volumes, masses, and intensities of accumulation of main sediment types for both Pleistocene subdivisions. A comparison of the results confirmed a strong increase in the rate of terrigenous sedimentation. Special attention was given to the evolution of siliceous and carbonate sedimentation of the biogenic type.

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Diatom stratigraphy of the late Pleistocene (Brunhes) subarctic Pacific

Cited by 44 publications

References 12 publications

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

Climatic change and CaCO₃ preservation: An 800,000 year bathymetric Reconstruction from the central equatorial Pacific Ocean

Facies structure and quantitative parameters of pleistocene pelagic sedimentation in the Indian Ocean

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Diatom stratigraphy of the late Pleistocene (Brunhes) subarctic Pacific

Cited by 44 publications

References 12 publications

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

Consistent relationship between global climate and surface nitrate utilization in the western subarctic Pacific throughout the last 500 ka

Climatic change and CaCO3 preservation: An 800,000 year bathymetric Reconstruction from the central equatorial Pacific Ocean

Facies structure and quantitative parameters of pleistocene pelagic sedimentation in the Indian Ocean

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Climatic change and CaCO₃ preservation: An 800,000 year bathymetric Reconstruction from the central equatorial Pacific Ocean