Variations in Atlantic surface ocean paleoceanography, 50°‐80°N: A time‐slice record of the last 30,000 years

Sarnthein, Michael; Jansen, Eystein; Weinelt, Mara; Arnold, Maurice; Duplessy, Jean Claude; Erlenkeuser, Helmut; Flatøy, Astrid; Johannessen, Gro; Johannessen, Truls; Jung, Simon; Koç, N.; Labeyrie, Laurent D; Maslin, Mark; Pflaumann, Uwe; Schulz, Hartmut

doi:10.1029/95pa01453

Cited by 293 publications

(190 citation statements)

References 75 publications

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“…The present study clearly supports the idea of an anti-phase temperature relationship between the North Icelandic shelf and the eastern North Atlandic during pre-Bølling time (see also Sarnthein et al, 1995). A subsequent cooling north of Iceland, which is especially pronounced for bottom waters, corresponds to the onset of the Norwegian Sea deep water formation.…”

Section: Comparison and Discussionsupporting

confidence: 74%

“…This has previously been demonstrated both for the areas around Iceland (e.g. Koç et al, 1993;Sarnthein et al, 1995 andVoelker et al, 1998) and from the shelf west of Iceland as well as north of Iceland Eiríksson et al, 2000a;Eiríksson et al, 2000b andAndrews et al, 2001a). Consistency between marine late Holocene proxies from the North Icelandic shelf and atmospheric and terrestrial data from the Greenland ice sheet and from Iceland glacier advances shows that there is a close relationship between the oceanic system and the atmospheric circulation in the region ( Eiríksson et al, 2000b;Andrews et al, 2001b;Andrews et al, 2001c;Giraudeau, 2002 andJiang et al, 2002).…”

Section: Introductionmentioning

confidence: 78%

“…One could argue that the low benthic and planktonic 18 O values were due to warm subsurface water flowing into the region north of Iceland in an anti-estuarine circulation mode. Such arguments were proposed by Sarnthein et al (1995) and Rasmussen et al, 1996 andRasmussen et al, 1997. However, if one calculates the ice volume corrected amplitude, the 2‰ benthic 18 O lowering at 15700 relative to 15000 cal yr BP would in this scenario imply that the bottom waters of the site were 8°C warmer at 15700 than at 15000 cal yr BP, using a relationship of 0.26‰ per degree C (Shackleton, 1974).…”

Section: The Lateglacial (15740-11500 Cal Yr Bp)mentioning

confidence: 98%

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Environmental changes off North Iceland during the deglaciation and the Holocene: foraminifera, diatoms and stable isotopes

Knudsen

Jiang

Jansen

et al. 2004

Marine Micropaleontology

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A combined study of foraminifera, diatoms and stable isotopes in marine sediments off North Iceland records major changes in sea surface conditions since about 15800 cal years (yr) BP. Results are presented from two gravity cores obtained at about 400 m water depth from two separate sedimentary basins on each side of the submarine Kolbeinsey Ridge. The chronology of the sedimentary record is based partly on AMS 14 C dates, partly on the Vedde and the Saksunarvatn tephra markers, as well as the historical Hekla AD 1104 tephra. During the regional deglaciation, the planktonic foraminiferal assemblages are characterised by consistently high percentages of sinistrally coiled Neogloboquadrina pachyderma. However, major environmental variability is reflected by changes in stable isotope values and diatom assemblages. Low 18 O values indicate a strong freshwater peak as well as possible brine formation by sea-ice freezing during a pre-Bølling interval (Greenland Stadial 2), corresponding to the Heinrich 1 event. The foraminifera suggest a strong concurrent influence of relatively warm and saline Atlantic water, and both the foraminifera and the diatoms suggest mixing of cold and warm water masses. Similar but weaker environmental signals are observed during the Younger Dryas (Greenland Stadial 1) around the level of the Vedde Ash. Each freshwater peak is succeeded by an interval of severe cooling both at the beginning of the Bølling-Allerød Interstadial Complex (Greenland Interstadial 1) and during the Preboreal, presumably associated with the onset of intense deep water formatiom in the Nordic Seas. The Holocene thermal optimum, between 10200 and about 7000 cal years (yr) BP, is interrupted by a marked cooling of the surface waters around 8200 cal yr BP. This cold event is clearly expressed by a pronounced increase in the percentages of sinistrally coiled N. pachyderma, corresponding to a temperature decrease of about 3°C. A general cooling in the area is indicated after 7000-6000 cal yr BP, both by the diatom data and by the planktonic foraminiferal data. After a severe cooling around 6000 cal yr BP, the planktonic foraminiferal assemblages suggest a warmer interval between 5500 and 4500 cal yr BP. Minor temperature fluctuations are reflected both in the foraminiferal and in the diatom data in the upper part of the record, but the time resolution of the present data is not high enough to pick up details in environmental changes through the late Holocene.

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Section: Comparison and Discussionsupporting

confidence: 74%

Section: Introductionmentioning

confidence: 78%

Section: The Lateglacial (15740-11500 Cal Yr Bp)mentioning

confidence: 98%

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Environmental changes off North Iceland during the deglaciation and the Holocene: foraminifera, diatoms and stable isotopes

Knudsen

Jiang

Jansen

et al. 2004

Marine Micropaleontology

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“…4; Table 3). This age lags 600-1000 years behind the ages found in dozens of benthic and planktonic δ 18 O records from the Atlantic (Winn et al, 1991;Sarnthein et al, 1995). The lag represents the time span needed for an ocean-wide spreading of the early deglacial δ 18 O signal and confirms previous estimates (800-1000 years; Duplessy et al, 1991).…”

Section: Linkages Of Monsoon To Global Climatic Change: Leads and Lagssupporting

confidence: 75%

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

et al. 1999

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Based on the study of 10 sediment cores and 40 core-top samples from the South China Sea (SCS) we obtained proxy records of past changes in East Asian monsoon climate on millennial to bidecadal time scales over the last 220,000 years. Climate proxies such as global sea level, estimates of paleotemperature, salinity, and nutrients in surface water, ventilation of deep water, paleowind strength, freshwater lids, fluvial and=or eolian sediment supply, and sediment winnowing on the sea floor were derived from planktonic and benthic stable-isotope records, the distribution of siliciclastic grain sizes, planktonic foraminifera species, and the U K 37 biomarker index. Four cores were AMS-14 C-dated. Two different regimes of monsoon circulation dominated the SCS over the last two glacial cycles, being linked to the minima and maxima of Northern Hemisphere solar insolation. (1) Glacial stages led to a stable estuarine circulation and a strong O 2 -minimum layer via a closure of the Borneo sea strait. Strong northeast monsoon and cool surface water occurred during winter, in part fed by an inflow from the north tip of Luzon. In contrast, summer temperatures were as high as during interglacials, hence the seasonality was strong. Low wetness in subtropical South China was opposed to large river input from the emerged Sunda shelf, serving as glacial refuge for tropical forest. (2) Interglacials were marked by a strong inflow of warm water via the Borneo sea strait, intense upwelling southeast of Vietnam and continental wetness in China during summer, weaker northeast monsoon and high sea-surface temperatures during winter, i.e. low seasonality. On top of the long-term variations we found millennial-to centennial-scale cold and dry, warm and humid spells during the Holocene, glacial Terminations I and II, and Stage 3. The spells were coeval with published variations in the Indian monsoon and probably, with the cold Heinrich and warm Dansgaard-Oeschger events recorded in Greenland ice cores, thus suggesting global climatic teleconnections. Holocene oscillations in the runoff from South China centered around periodicities of 775 years, ascribed to subharmonics of the 1500-year cycle in oceanic thermohaline circulation. 102=84-year cycles are tentatively assigned to the Gleissberg period of solar activity. Phase relationships among various monsoon proxies near the onset of Termination IA suggest that summer-monsoon rains and fluvial runoff from South China had already intensified right after the last glacial maximum (LGM) insolation minimum, coeval with the start of Antarctic ice melt Wang et al. / Marine Geology 156 (1999) prior to the δ 18 O signals of global sea-level rise. Vice versa, the strength of winter-monsoon winds decreased in short centennial steps only 3000-4000 years later, along with the melt of glacial ice sheets in the Northern Hemisphere.

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“…Low d 13 C of N. pachyderma sin. clearly delineates nutrient maxima near the pycnocline in stratified surface waters of the modern and late Pleistocene northern North Atlantic [Sarnthein et al, 1995;Simstich et al, 2002].…”

Section: Tracers Of Nutrient Concentration and Bottom Water Ventilationmentioning

confidence: 99%

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Gebhardt¹,

Sarnthein²,

et al. 2008

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[1] Our study addresses fundamental questions of the mode and timing of orbital and millennial-scale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past abundance of nutrients in surface waters despite strong stratification, and the North Pacific-North Atlantic seesaw of oscillations in sea surface temperature (SST). We do this by generating and interpreting multiple records for glacial terminations I-V down two long piston cores, one each from the western and eastern subarctic Pacific. Chlorins and biogenic opal are proxies for surface water productivity; d 13 C of epibenthic foraminifera is a record of deepwater ventilation; and the d 13 C of N. pachyderma sin. is a tracer of nutrients in subsurface waters that extend up to the sea surface during times of vertical mixing. The degree of mixing is traced by pairing SST and d 18 O records of planktic surface and subsurface (pycnocline) dwellers. Tight age control is deduced from a suite of age-calibrated 14 C plateau boundaries for Termination I and benthic d 18 O and geomagnetic events for the last 800 ka. Carbon 14 paleoreservoir ages record the ages of surface and deep waters to uncover short-term changes in MOC over Termination I. We have defined a standard sequence of short-term productivity events for Termination I, also evident during terminations II to V and subsequent interglacials over the last 450 ka. The peak glacial regime of stable stratification and low productivity terminated, together with the end of ice rafting and melting, near 17 ka, $2000 years after the onset of Termination I. Pulses of vertical mixing and incursion of warm surface waters from the subtropics followed. Convected young water masses finally penetrated down to 3600-m water depth at 17.0 to less than 14.5 ka, significantly improving bottom water ventilation through the late deglacial and earliest interglacial. Mixing with upwelled nutrients from the pycnocline induced short-term maxima in algal production of chlorins and biogenic opal near 17-15 and 15-12 ka, respectively. Deglacial meltwater incursions in the Aleutian Current and silica input from North American rivers also promoted East Pacific productivity after 15.5 ka. Productivity decreased during the late deglacial and early interglacial, coeval with an exceptional peak in CaCO 3 preservation caused by both low organic flux and well-ventilated deepwater. Subsequently, low salinity and cool surface waters and in turn, stratification were gradually restored. A second, opaldominated productivity maximum marked the ends of interglacials. The deglacial pulses of vertical mixing around 17-11 ka imply an important contribution of the North Pacific to the coeval release of oceanic CO 2 into the atmosphere and support the east-west seesaw model of climate change.Citation: Gebhardt, H., M. Sarnthein, P. M. Grootes, T. Kiefer, H. Kuehn, F. Schmieder, and U. Röhl (2008), Paleonutrient and productivity records from the subarctic North ...

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Variations in Atlantic surface ocean paleoceanography, 50°‐80°N: A time‐slice record of the last 30,000 years

Cited by 293 publications

References 75 publications

Environmental changes off North Iceland during the deglaciation and the Holocene: foraminifera, diatoms and stable isotopes

Environmental changes off North Iceland during the deglaciation and the Holocene: foraminifera, diatoms and stable isotopes

East Asian monsoon climate during the Late Pleistocene: high-resolution sediment records from the South China Sea

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

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