cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.1594/pangaea.831621
title: (Table 3) Age determination of sediment core HLY02-02-51

description: The Bering Sea gateway between the Pacific and Arctic oceans impacts global climate when glacial-interglacial shifts in shore line position and ice coverage change regional albedo. Previous work has shown that during the last glacial termination and into the Holocene, sea level rises and sea ice coverage diminishes from perennial to absent. Yet, existing work has not quantified sea ice duration or sea surface temperatures (SST) during this transition. Here we combine diatom assemblages with the first alkenone record from the Bering Sea to provide a semiquantitative record of sea ice duration, SST, and productivity change since the Last Glacial Maximum (LGM). During the LGM, diatom assemblages indicate that sea ice covered the southeastern Bering Sea perennially. At 15.1 cal ka B.P., the diatom assemblage shifts to one more characteristic of seasonal sea ice and alkenones occur in the sediments in low concentrations. Deglaciation is characterized by laminated intervals with highly productive and diverse diatom assemblages and inferred high coccolithophorid production. At 11.3 cal ka B.P. the diatom assemblage shifts from one dominated by sea ice species to one dominated by a warmer water, North Pacific species. Simultaneously, the SST increases by 3°C and the southeastern Bering Sea becomes ice-free year-round. Productivity and temperature proxies are positively correlated with independently dated records from elsewhere in the Bering Sea, the Sea of Okhotsk, and the North Pacific, indicating that productivity and SST changes are coeval across the region.
description: Measured on Neogloboquadrina pachyderma sinistral.
description: Supplement to: Caissie, Beth; Brigham-Grette, Julie; Lawrence, Kira T; Herbert, Timothy D; Cook, Mea S (2010): Last Glacial Maximum to Holocene sea surface conditions at Umnak Plateau, Bering Sea, as inferred from diatom, alkenone, and stable isotope records. Paleoceanography, 25(1), PA1206
DOI: 10.1594/pangaea.829696
title: (Table S1) Age determination of sediment core RAPiD-21-03K

description: A decadal resolution time series of sea surface temperature (SST) spanning the last two millennia is reconstructed by combining a proxy record from a new sediment sequence with previously published data from core MD99-2275, north of Iceland. The alkenone based SST reconstruction is validated with historic observational data and compared to a new similar temporal resolution reconstruction obtained from sediment core RAPiD21-3K, in the subpolar North Atlantic. The two SST paleorecords show consistent multidecadal scale coolings throughout the interval and similar expressions during the contrasted climatic periods 'colloquially known' as the Medieval Climatic Anomaly (MCA) and Little Ice Age (LIA). In order to further understand the temporal and spatial SST variations and investigate the influence of natural forcings on the observed SST changes during the last millennium, we compare our time series to simulations using the Institut Pierre-Simon Laplace IPSLCM4-v2 climate model. This comparison highlights the potential importance of volcanism as a natural forcing driving coherent abrupt cooling events captured in the subpolar North Atlantic records.
description: All measurements were made using the species Globigerina bulloides.
description: Supplement to: Sicre, Marie-Alexandrine; Hall, Ian R; Mignot, J; Kohdri, M; Ezat, Ullah; Truong, M-X; Eiriksson, Jón; Knudsen, Karen Luise (2011): Sea surface temperature variability in the subpolar Atlantic over the last two millennia. Paleoceanography, 26(4), PA4218
DOI: 10.1594/pangaea.57430
title: tab 1
DOI: 10.1594/pangaea.711149
title: Age control points of sediment core GeoB6211-2
DOI: 10.1594/pangaea.706166
title: (Table 4) 40Ar/39Ar ages and replicate runs for eolian extract from sediment core MV0502-01JC

description: Estimated stratigraphic age (AGE) from Sr fish teethmodel (Table 1, data set: doi:10.1594/PANGAEA.706161 and Appendix A, data set: doi:10.1594/PANGAEA.706159). Total gas age is equivalent to 40Ar/39Ar retention ages reported by Pettke et al. (2000, doi:10.1016/S0012-821X(00)00083-2), integrated over all heating steps without the 39Ar recoil fraction (equivalent to conventional 40Ar/39Ar bulk melting age - Pettke et al., 2000; Dong et al., 1995, doi:10.1126/science.267.5196.355).
DOI: 10.1594/pangaea.829978
title: (Table S1) Age determination of sediment cores SK99_17 and MD76-131

description: Productivity in the Arabian Sea is one of the highest in the world. It is controlled by seasonally reversing monsoonal wind-driven upwelling of nutrient-rich deeper waters which fuel phytoplankton growth. The detailed history of upwelling-induced productivity in the eastern Arabian Sea is unknown. Here we present paleoproductivity records from a composite sediment core at the millennial scale during the last 80 kyr B.P. These records are based on relative abundance counts of planktonic foraminifera and organic carbon contents, which are shown to mainly vary in concert. The eastern Arabian Sea upwelling-induced productivity was higher in the glacial period than in the Holocene, but it fell repeatedly on millennial timescales. These productivity declines occurred during cold events in the North Atlantic region, with the most pronounced changes prevailing during the Heinrich events. Hence, seasonal monsoon winds that drive upwelling-induced productivity in the east were weak when the North Atlantic was cold. These weak winds resulted in stratification of the water column, comparable to today's Arabian Sea stratification in the intermonsoonal period. Combining the new eastern with published western Arabian Sea results shows that the entire biological factory was severely diminished during the North Atlantic Heinrich events, and the seasonal productivity change in the Arabian Sea monsoon system was reduced with year-round low productivity.
description: Ages of MD76-131 adopted from Ivanochkov (2005).
description: Supplement to: Singh, Arun Deo; Jung, Simon J A; Darling, Kate F; Ganeshram, Raja S; Ivanochko, Tara S; Kroon, Dick (2011): Productivity collapses in the Arabian Sea during glacial cold phases. Paleoceanography, 26(3), PA3210
DOI: 10.1594/pangaea.56534
title: (Table 2) Conventional radiocarbon ages and stable carbon isotope values of fossil plant material from the Labaz Lake area
DOI: 10.1594/pangaea.830637
title: (Table S1) Age determination of sediment cores of the Ontong Java Plateau

description: We present a reconstruction of deep-water carbonate saturation state (Delta [CO3]2-) in the western equatorial Pacific for the Last Glacial Maximum (LGM) and deglaciation based on changes in the Mg/Ca ratio of planktic foraminifers with increased water depth. Our data suggest there have been changes in bottom waterDelta [CO3]2- over the past 25,000 years at water depths as shallow as 1.6 km. The Delta [CO3]2- reconstruction for the LGM suggests Delta [CO3]2- was similar or slightly higher than modern values between 1.6 and 2.0 km, shifting sharply to lower values (an average ~30 µmol/kg lower) below 2.5 km. The shift in chemistry between 2.0 and 2.5 km supports a hypothesis that Pacific overturning circulation occurred deeper during the LGM with a slightly more ventilated water mass above 2.0 km. The data are not consistent with enhanced preservation in this region of the deep Pacific at depths greater than 2.5 km, suggesting that the long-held view of better preservation throughout the glacial deep Pacific must be reevaluated. For the deglaciation, we have evidence of a Delta [CO3]2- maximum that suggests enhanced deglacial preservation between 1.6 and 4.0 km in comparison to the Holocene and the LGM. The deglacial Delta [CO3]2- was as much as 28 µmol/kg higher than modern between 1.6 and 4.0 km. Results suggest carbonate burial rates were 1.5 times greater during the deglacial than the over the past 5 kyr.
description: Measured on Globigerinoides sacculifer. The radiocarbon age was converted to calendar age by first adjusting ages for the estimated reservoir age for this region (256 years) and then converting to calendar age using the online calibration tool located at http://radiocarbon.ldeo.columbia.edu/research/radcarbcal.htm (Fairbanks et al, 2005).
description: Supplement to: Fehrenbacher, Jennifer; Martin, Pamela (2011): Western equatorial Pacific deep water carbonate chemistry during the Last Glacial Maximum and deglaciation: Using planktic foraminiferal Mg/Ca to reconstruct sea surface temperature and seafloor dissolution. Paleoceanography, 26(2), PA2225
DOI: 10.1594/pangaea.407585
title: Age determination of sediment core IN68-22

description: No corrections have been made for reservoir age.
DOI: 10.1594/pangaea.831405
title: (Table S4b) Concentrations and accumulation rates of CaCO3 and biogenic barium for ODP Site 119-738

description: DEPTH, sediment/rock [m] is given in mbsf.
DOI: 10.1594/pangaea.824858
title: (Table S1) Age determination of sediment cores of the Azores Current System

description: In order to test the sensitivity of marine primary productivity in the midlatitude open ocean North Atlantic to changes in the Atlantic Meridional Overturning Circulation (AMOC), we investigated two spliced sediment cores from a site south of the Azores Islands at the northern rim of the North Atlantic subtropical gyre. For this purpose we analyzed coccolithophore assemblages, diatom abundances, alkenones and conducted X-ray fluorescence (XRF) core scanning. During times of reduced AMOC, especially during Heinrich event 1 (H1) and the Younger Dryas, we observe a strong increase in productivity as evidenced by high coccolith accumulation rates, high alkenone concentrations/accumulation rates, high Ba/Ti-ratios, high abundances of diatoms and low abundances ofF. profunda. The increased productivity is partly caused by a more southern position of the Azores Front (AzF), and hence by a less northward extension of the subtropical gyre, as deduced from high abundances of the temperate coccolithophore species G. muellerae and low abundances of subtropical species (Oolithotus spp., Umbellosphaera spp., Umbilicosphaeraspp.). However, to explain the full range of the observed productivity increase, other factors like increased westerly winds and advection of nutrient-rich surface waters have also to be considered. Because this pattern can also be observed in other sediment cores from the midlatitude North Atlantic, we propose that during times of reduced AMOC there has been a band of strongly increased productivity across the North Atlantic at the northern rim of the contracted subtropical gyre, which partly counteracts the decreased organic carbon pump in the high northern latitudes.
description: AMS determination on monospecific planktonic foraminifera (Globigerinoides runber white or Globigerina bulloides).
description: Supplement to: Schwab, Christian; Kinkel, Hanno; Weinelt, M; Repschläger, Janne (2012): Coccolithophore paleoproductivity and ecology response to deglacial and Holocene changes in the Azores Current System. Paleoceanography, 27(3), PA3210
DOI: 10.1594/pangaea.833945
title: (Table 2) Age determination of sediment core MD99-2283

description: he timing of meltwater release in the southern Norwegian Sea in relation to millennial-scale climate variability is studied from core MD99-2283 based on down-core analysis of stable oxygen and carbon isotopes, calcium carbonate and ice-rafted debris (IRD). Between 20 and 40 calendar (cal) kyr B.P., strong Dansgaard-Oeschger cyclicity is expressed in increased carbonate content and reduced total organic carbon during warm interstadials and IRD marking the end of cold stadials. The planktonic d18O record of core MD99-2283 compared to available isotopic records in the region confirms the existence of multisourced, synchronized meltwater anomalies during Heinrich (H) events 2 to 4. It was found that the sudden release of meltwater occurs near major ice streams and that no significant increase in IRD was associated with the peaks of the meltwater events in the southern Norwegian Sea, suggesting meltwater discharges from ice-dammed lakes. Significant meltwater events not related to the H events were also observed between 33 and 35 cal kyr B.P., indicating that the release of meltwater is not necessarily connected with major cooling and enhanced IRD delivery. The simultaneous release of fresh water during H events in the Nordic Seas, through icebergs and ice-dammed lakes, is thought to be the result of sea level increase. The meltwater input to the Nordic Seas provides a significant additional contribution to global sea level rise associated with H3 and H4.
description: Supplement to: Lekens, W; Sejrup, Hans Petter; Haflidason, Haflidi; Knies, Jochen; Richter, Thomas (2006): Meltwater and ice rafting in the southern Norwegian Sea between 20 and 40 calendar kyr B.P.: Implications for Fennoscandian Heinrich events. Paleoceanography, 21(3), PA3013
DOI: 10.1594/pangaea.825548
title: (Table 1) Age determination of sediment core MD02-2515

description: Centennial-scale records of sea-surface temperature and opal composition spanning the Last Glacial Maximum and Termination 1 (circa 25-6 ka) are presented here from Guaymas Basin in the Gulf of California. Through the application of two organic geochemistry proxies, the UK37' index and the TEX86H index, we present evidence for rapid, stepped changes in temperatures during deglaciation. These occur in both temperature proxies at 13 ka (~3°C increase in 270 years), 10.0 ka (~2°C decrease over ~250 years) and at 8.2 ka (3°C increase in &lt;200 years). An additional rapid warming step is also observed in TEX86H at 11.5 ka. In comparing the two temperature proxies and opal content, we consider the potential for upwelling intensity to be recorded and link this millennial-scale variability to shifting Intertropical Convergence Zone position and variations in the strength of the Subtropical High. The onset of the deglacial warming from 17 to 18 ka is comparable to a "southern hemisphere" signal, although the opal record mimics the ice-rafting events of the north Atlantic (Heinrich events). Neither the modern seasonal cycle nor El Niño/Southern Oscillation patterns provide valid analogues for the trends we observe in comparison with other regional records. Fully coupled climate model simulations confirm this result, and in combination we question whether the seasonal or interannual climate variations of the modern climate are valid analogues for the glacial and deglacial tropical Pacific.
description: Supplement to: McClymont, Erin L; Ganeshram, Raja S; Pichevin, Laetitia; Talbot, Helen M; van Dongen, Frank H; Thunell, Robert C; Haywood, Alan M; Singarayer, Joy S; Valdes, Paul J (2012): Sea-surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change. Paleoceanography, 27(2), PA2202
DOI: 10.1594/pangaea.921797
title: Radiocarbon measurements on tree rings of tree BLS-B10
DOI: 10.1594/pangaea.921807
title: Radiocarbon measurements on tree rings of tree ZH-644415
DOI: 10.1594/pangaea.829501
title: (Table S1) Age determination of sediment core MD99-2251

description: Evidence from a North Atlantic deep-sea sediment core reveals that the largest climatic perturbation in our present interglacial, the 8200-year event, is marked by two distinct cooling events in the subpolar North Atlantic at 8490 and 8290 years ago. An associated reduction in deep flow speed provides evidence of a significant change to a major downwelling limb of the Atlantic meridional overturning circulation. The existence of a distinct surface freshening signal during these events strongly suggests that the sequenced surface and deep ocean changes were forced by pulsed meltwater outbursts from a multistep final drainage of the proglacial lakes associated with the decaying Laurentide Ice Sheet margin.
description: Supplement to: Ellison, Christopher RW; Chapman, Mark R; Hall, Ian R (2006): Surface and deep ocean interactions during the Cold Climate Event 8200 years ago. Science, 312(5782), 1929-1932
DOI: 10.1594/pangaea.921803
title: Radiocarbon measurements on tree rings of tree STK-C34
DOI: 10.1594/pangaea.388978
title: Facies log and age determinations of profile BAP1 from Taymyr Peninsula
DOI: 10.1594/pangaea.921805
title: Radiocarbon measurements on tree rings of tree TAT-C13
DOI: 10.1594/pangaea.760146
title: (Table 2) 40Ar/39Ar total fusion ages of ODP Leg 120 samples

description: Total fusion temperature = 1500°C.
DOI: 10.1594/pangaea.830646
title: (Table 1) Age determination of sediment cores JM97-948/2A and MD95-2011

description: A high-resolution sediment core from the Vøring Plateau has been studied to document the centennial to millennial variability of the surface water conditions during the Holocene Climate Optimum (HCO) and the late Holocene period (LHP) in order to evaluate the effects of solar insolation on surface ocean climatology. Quantitative August summer sea surface temperatures (SSSTs) with a time resolution of 2-40 years are reconstructed by using three different diatom transfer function methods. Spectral- and scale-space methods are applied to the records to explore the variability present in the time series at different time scales. The SSST development in core MD95-2011 shows a delayed response to Northern Hemisphere maximum summer insolation at ~11,000 years B.P. The record shows the maximum SSST of the HCO to be from 7.3 to 8.9 kyr B.P., which implies that the site was located in the regional warm water pool removed from the oceanic fronts and Arctic waters. Superimposed on the general cooling trend are higher-frequency variabilities at time scales of 80-120, 210-320, 320-640, and 640-1280 years. The climate variations at the time scale of 320-640 years are documented both for periods of high and low solar orbital insolation. We found evidence that the submillennial-scale mode of variability (640-900 years) in SSST evident during the LHP is directly associated with varying solar forcing. At the shorter scale of 260-450 years, the SSST during the LHP displays a lagged response to solar forcing with a phase-locked behavior indicating the existence of a feedback mechanism in the climate system triggered by variations in the solar constant as well as the role of the thermal inertia of the ocean. The abruptness of the cooling events in the LHP, especially pronounced during the onsets of the Holocene Cold Period I (approximately 2300 years B.P.) and the Little Ice Age (approximately 550 years B.P.), can be explained by a shutdown of deep convection in the Nordic Seas in response to negative solar insolation anomalies. These cooling events are on the order of 1.5°C.
description: The measurements are made on the foraminifer species N. pachyderma (dex) and N. pachyderma (sin). The age of the Vedde ash layer is the GRIP age from Grönvold et al. (1995, doi:10.1016/0012-821X(95)00145-3). The dates were calibrated with the MARINE04 calibration curve, with Delta R of 0 ± 20 in the Holocene, and Delta R of 300 ± 20 in the pre-Holocene. The age-depth model uses a mixed-effect regression procedure, which uses the midpoint of the 1s ranges rather than the intercept as a point estimate of the 14C dates, described by Heegaard et al. (2005, doi:10.1191/0959683605hl836rr).
description: Supplement to: Berner, K S; Koç, Nalân; Godtliebsen, Fred; Divine, Dmitry V (2011): Holocene climate variability of the Norwegian Atlantic Current during high and low solar insolation forcing. Paleoceanography, 26(2), PA2220
DOI: 10.1594/pangaea.831673
title: (Table S1) Age determination of Florida Straits sediment cores
DOI: 10.1594/pangaea.884358
title: Sediment data from the pingo exposure AWI_12P-2008-A

description: Three profiles (12P-1908-A, 12P-2008-A, 12P-2208-A) of exposed deposits were sampled in course of the expedition Pokhodsk 2012 in the Kolyma Lowland, which contained frozen sediments. The samples were afterward analysed for granulometry, magnetic susceptibility, organic matter composition (TOC, TC, TIC, TN, TOC/TN, d13C), and radiocarbon dated.
DOI: 10.1594/pangaea.186260
title: Radiocarbon age determinations on sediment core V22-177
DOI: 10.1594/pangaea.831235
title: (Table 1) Age determination of ODP Hole 146-893A

description: To better understand the deglacial upwelling pattern in the east Pacific, we have made radiocarbon (14C) measurements on benthic foraminifera and macrofauna from a 3.5 m long interval in ODP Core 893A from Santa Barbara Basin, California, representing early deglaciation. This work serves to investigate the source of apparent disagreement between radiocarbon data sets from Leibnitz Laboratory, Kiel University (Kiel) and Carbon Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory (LLNL). These data sets are based on measurements of mixed benthic and mixed planktonic foraminifera. Interlaboratory 14C results are similar for the planktonic foraminiferal analyses; however, Kiel measurements on mixed benthic foraminifera are much older than mixed benthic measurements from equivalent depths measured at LLNL. Our new results show distinct 14C differences between taxa, with Pyrgo sp. giving ages consistently older than Kiel measurements on mixed benthic taxa, while ages for Nonionellina sp., Buliminella sp., Uvigerina sp., and benthic macrofauna were much younger, even younger than the LLNL mixed benthic data. The new data supports benthic-planktonic age offsets of no more than 300 years, indicating that bottom waters within the basin remained significantly younger during early deglaciation than some previous results have suggested and are thus consistent with sedimentary and faunal evidence for well-oxygenated conditions.
description: DEPTH, sediment/rock [m] is given in mbsf. This dataset shows data from Hendy et al., (2002) and Sarnthein et al., (2007), plus new 14C data from this study. Lawrence Livermore National Laboratory 14C results originally published in Ingram and Kennett [1995] were recalculated in Hendy et al. (2002) to properly correct for the presence of 14C-dead carbon as well as modern carbon in 14C small-sample processing backgrounds. All data have been placed on the Hendy et al. (2002) depth scale for ODP 893A: void-corrected depths within each ODP core section were calculated based on Merrill and Beck (1995), and these are keyed to the sectiontop depths of Behl (1995). We have followed Hendy et al. (2002) in correcting the Behl (1995) depths for 1.5 m and 0.75 m of missing core at the 1H-2H and 2H-3H section boundaries, respectively, and in our use of 27.7 m for the top of 4H1 rather than the adjusted Behl (1995) depth of 25.8 + 2.25 m (see the 4H1 depths shown in Hendy et al. (2002, Table 3)).
description: Supplement to: Magana, Alexandra L; Southon, John R; Kennett, James P; Roark, E Brendan; Sarnthein, Michael; Stott, Lowell D (2010): Resolving the cause of large differences between deglacial benthic foraminifera radiocarbon measurements in Santa Barbara Basin. Paleoceanography, 115(4), PA4102
DOI: 10.1594/pangaea.868712
title: Age determination of sediment core PAR87A-01
DOI: 10.1594/pangaea.712847
title: (Table 4) Age determination on sediment core 9408
DOI: 10.1594/pangaea.863938
title: Stable isotopic composition of Cibicidoides wuellerstorf of ODP Hole 161-978A