Comparison of Atlantic and Pacific paleochemical records for the last 215,000 years: changes in deep ocean circulation and chemical inventories

Boyle, E.A.; Keigwin, Lloyd D

doi:10.1016/0012-821x(85)90154-2

Cited by 668 publications

(417 citation statements)

References 31 publications

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“…Most modern techniques of sample preparation for measurement of foraminiferal Mg/Ca ratios follow the general procedures developed by Boyle (1981), Boyle and Keigwin (1985) and Lea and Boyle (1991) for the determination of foraminiferal Cd/Ca and Ba/Ca ratios. The general requirements for cleaning foraminiferal calcite prior to Mg/Ca analysis are the removal of silicate phases (predominantly clays from within the test), organic matter and potentially a Mn-oxide coating.…”

Section: Methodsmentioning

confidence: 99%

“…3). Reductive cleaning involves bathing the sample in a hot buffered solution of hydrazine (Boyle and Keigwin, 1985) and causes some dissolution of foraminiferal carbonate. Since partial dissolution is known to cause a lowering of Mg/Ca ratios (see later), the reduction in Mg/Ca during reductive cleaning may be due either to removal of a contaminant phase or to the partial dissolution that occurs as a side-effect of reductive cleaning.…”

Section: Methodsmentioning

confidence: 99%

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Planktonic foraminiferal Mg/Ca as a proxy for past oceanic temperatures: a methodological overview and data compilation for the Last Glacial Maximum

Barker

Cacho

Benway

et al. 2005

Quaternary Science Reviews

236

163

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As part of the Multi-proxy Approach for the Reconstruction of the Glacial Ocean (MARGO) incentive, published and unpublished temperature reconstructions for the Last Glacial Maximum (LGM) based on planktonic foraminiferal Mg/Ca ratios have been synthesised and made available in an online database. Development and applications of Mg/Ca thermometry are described in order to illustrate the current state of the method. Various attempts to calibrate foraminiferal Mg/Ca ratios with temperature, including culture, trap and core-top approaches have given very consistent results although differences in methodological techniques can produce offsets between laboratories which need to be assessed and accounted for where possible. Dissolution of foraminiferal calcite at the sea-floor generally causes a lowering of Mg/Ca ratios. This effect requires further study in order to account and potentially correct for it if dissolution has occurred. Mg/Ca thermometry has advantages over other paleotemperature proxies including its use to investigate changes in the oxygen isotopic composition of seawater and the ability to reconstruct changes in the thermal structure of the water column by use of multiple species from different depth and or seasonal habitats. Presently available data are somewhat limited to low latitudes where they give fairly consistent values for the temperature difference between Late Holocene and the LGM (2-3.5 1C). Data from higher latitudes are more sparse, and suggest there may be complicating factors when comparing between multi-proxy reconstructions. r

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Planktonic foraminiferal Mg/Ca as a proxy for past oceanic temperatures: a methodological overview and data compilation for the Last Glacial Maximum

Barker

Cacho

Benway

et al. 2005

Quaternary Science Reviews

236

163

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“…Changes in northern hemisphere (particularly North American) ice volume dominate the o 18 0 trends, and general circulation modeling experiments show that ice in North America affects North Atlantic SST and sea ice extent by altering surface winds over the ocean [Manabe and Broccoli, 1985;Broccoli and Manabc, 1987]. These ice sheet effects on the North Atlantic also impact the productivity of foraminifera and coccoliths in surface waters and thus the CaC~ content of the sediments, as docs continental sediment rafted from the ice sheets to the ocean via icebergs [Ruddiman, 1977].…”

Section: Internal Linkages Within the Climate Systemmentioning

confidence: 99%

Pleistocene evolution: Northern hemisphere ice sheets and North Atlantic Ocean

Ruddiman¹,

Raymo²,

Martinson³

et al. 1989

Paleoceanography

791

467

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Abs~ract. We analy:ro five high-resolution time series spanmng the last 1.65 m.y.: benthic foraminiferal 5110 and 5'~C. percent CaC03o and estimated sea surface temperature (SS1) at Nonh Atlantic Deep Sea Drilling Project site 007 and percent CaC~ at site 609. E ach record is a multicore compo<;ite verifiC;d fo~ c?nti.nuity by splicing among multiple hole~. The~e chmauc. mdtces portray changes in northern hemtsphere tee sheet stze and in North Atlantic surface and deep circulation. By tuning obliquity and precession components in the 5 11 0 record to orbital variations we have devised a time scale (TP607) for the entire Pleist~ene that agrees in age with aU K/Ar-dated magnetic reversals to within 1.5%. The Brunhes time scale is taken from Imbrie et al. (1984], except for differences near the stage 17/16 transition (0.70 to 0.64 Ma). All indicators show a similar evolution from the ~uyama to the B.runhes chrons: orbital eccentricity and_ prece~1o.n responses mcreased in amplitude; those at orbttal obliqutty decreased. The change in dominance from Paper number 89PA00434. 0883-8305/89/89PA-00434$10.00 obliquity to eccentricity occurred over several hundred thousand years, with fa stest changes around 0.7 to 0.6 Ma. The coherent, in-phase responses of 5"0. 5 1 3C, CaC03 and SST at these rhythms indicate that northern hemisphere ice volume changes have controlled most of the North Atlantic surfaceocean and deep-ocean responses for the last 1.6 m.y. Tbe 5 1 3C, percent CaCO; and SST records at site 607 also show prominent changes at low frequencies, including a prominent long-wavelength oscillation toward glacial conditions that is centered between 0.9 and 0.6 Ma These changes appear to be associated neither with orbital forcing nor with changes in ice volume.

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“…In addition to changes in water-mass mixing, nutrient-based proxies are controlled by changes in export productivity and pre-formed nutrient contents of a water mass. Along with C isotopic fractionation during air−sea CO 2 exchange, these factors likely cause disagreement between the different nutrient proxy records, such as benthic foraminiferal δ 13 C and Cd/Ca in the South Atlantic and Southern Oceans (Boyle and Keigwin, 1985;Charles and Fairbanks, 1992;Charles et al, 1996;Lea, 1995;Lynch-Steiglitz and Fairbanks, 1994;Mackensen et al, 1996;Rickaby et al, 2000). The combination of slower flow speeds with higher productivity and regenerated nutrient contents in the Indian and Pacific Oceans has the potential to cause ambiguity when interpreting whether nutrient proxy records (Naqvi et al, 1994;Waelbroeck et al, 2006) (Jacobsen and Wasserburg, 1980); vary between deep-water masses of different provenance.…”

Section: Introductionmentioning

confidence: 99%

Indian Ocean circulation and productivity during the last glacial cycle

Piotrowski

Banakar

Scrivner

et al. 2009

Earth and Planetary Science Letters

106

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The Indian Ocean is an important part of the global thermohaline circulation system, receiving deep waters sourced from the Southern Ocean and being the location of upwelling and surface-ocean current flow, which returns warm and salty waters to the Atlantic. It is also an ideal location to reconstruct the link between thermohaline circulation and deep-water nutrient contents. No mixing occurs between major deep-water masses along flow paths within the Indian Ocean, so changes in water-mass provenance reflect changes in deep-ocean circulation while nutrient contents reflect addition and dissolution of organic matter. We present neodymium (Nd) and carbon (C) isotope records, proxies of water-mass provenance and nutrient contents, respectively, from an equatorial Indian Ocean core (SK129−CR2) spanning the last 150 kyr. The Nd isotope record shows that an increased proportion of North Atlantic Deep Water (NADW) reached the Indian Ocean during interglacials (marine isotope stages, MIS 1 and 5), and a reduced proportion during glacials (MIS 2, 4, and 6), and also that changes occurred during

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Comparison of Atlantic and Pacific paleochemical records for the last 215,000 years: changes in deep ocean circulation and chemical inventories

Cited by 668 publications

References 31 publications

Planktonic foraminiferal Mg/Ca as a proxy for past oceanic temperatures: a methodological overview and data compilation for the Last Glacial Maximum

Planktonic foraminiferal Mg/Ca as a proxy for past oceanic temperatures: a methodological overview and data compilation for the Last Glacial Maximum

Pleistocene evolution: Northern hemisphere ice sheets and North Atlantic Ocean

Indian Ocean circulation and productivity during the last glacial cycle

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