scholarly journals Connecting the Greenland ice-core and U / Th timescales via cosmogenic radionuclides: Testing the synchronicity of Dansgaard-Oeschger events

2018 ◽  
Author(s):  
Florian Adolphi ◽  
Christopher Bronk Ramsey ◽  
Tobias Erhardt ◽  
R. Lawrence Edwards ◽  
Hai Cheng ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
Cosmogenic Radionuclides ◽  
Last Glacial Period ◽  
Temperature Changes ◽  
Proxy Records ◽  
Atmospheric Fronts ◽  
Absolute Dating ◽  
The Last Glacial ◽  
Ice Core Records

Abstract. During the last glacial period Northern Hemisphere climate was characterized by extreme and abrupt climate changes, so-called Dansgaard-Oeschger (DO) events. Most clearly observed as temperature changes in Greenland ice-core records, their climatic imprint was geographically widespread. However, the temporal relation between DO-events in Greenland and other regions is uncertain due to the chronological uncertainties of each archive, limiting our ability to test hypotheses of synchronous change. On the contrary, the assumption of direct synchrony of climate changes forms the basis of many timescales. Here, we use cosmogenic radionuclides (10Be, 36Cl, 14C) to link Greenland ice-core records to U / Th-dated speleothems, quantify offsets between both timescales, and improve their absolute dating back to 45 000 years ago. This approach allows us to test the assumption that DO-events occurred synchronously between Greenland ice-core and tropical speleothem records at unprecedented precision. We find that the onset of DO-events occurs within synchronization uncertainties in all investigated records. Importantly, we demonstrate that there remain local discrepancies in the temporal development of rapid climate change for specific events and speleothems. These may be either related to the location of proxy records relative to the shifting atmospheric fronts or to underestimated U / Th-dating uncertainties. Our study thus highlights the potential for misleading interpretations of the Earth system when applying the common practice of climate wiggle-matching.

scholarly journals Connecting the Greenland ice-core and U∕Th timescales via cosmogenic radionuclides: testing the synchroneity of Dansgaard–Oeschger events

2018 ◽  
Vol 14 (11) ◽  
pp. 1755-1781 ◽  
Author(s):  
Florian Adolphi ◽  
Christopher Bronk Ramsey ◽  
Tobias Erhardt ◽  
R. Lawrence Edwards ◽  
Hai Cheng ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
Cosmogenic Radionuclides ◽  
Last Glacial Period ◽  
Temperature Changes ◽  
Proxy Records ◽  
Atmospheric Fronts ◽  
Absolute Dating ◽  
The Last Glacial ◽  
Ice Core Records

Abstract. During the last glacial period Northern Hemisphere climate was characterized by extreme and abrupt climate changes, so-called Dansgaard–Oeschger (DO) events. Most clearly observed as temperature changes in Greenland ice-core records, their climatic imprint was geographically widespread. However, the temporal relation between DO events in Greenland and other regions is uncertain due to the chronological uncertainties of each archive, limiting our ability to test hypotheses of synchronous change. In contrast, the assumption of direct synchrony of climate changes forms the basis of many timescales. Here, we use cosmogenic radionuclides (10Be, 36Cl, 14C) to link Greenland ice-core records to U∕Th-dated speleothems, quantify offsets between the two timescales, and improve their absolute dating back to 45 000 years ago. This approach allows us to test the assumption that DO events occurred synchronously between Greenland ice-core and tropical speleothem records with unprecedented precision. We find that the onset of DO events occurs within synchronization uncertainties in all investigated records. Importantly, we demonstrate that local discrepancies remain in the temporal development of rapid climate change for specific events and speleothems. These may either be related to the location of proxy records relative to the shifting atmospheric fronts or to underestimated U∕Th dating uncertainties. Our study thus highlights the potential for misleading interpretations of the Earth system when applying the common practice of climate wiggle matching.

scholarly journals An improved method for delta <sup>15</sup>N measurements in ice cores

2008 ◽  
Vol 4 (1) ◽  
pp. 149-171 ◽  
Author(s):  
F. S. Mani ◽  
P. Dennis ◽  
W. T. Sturges ◽  
R. Mulvaney ◽  
M. Leuenberger
Keyword(s):  
High Precision ◽  
Climate Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Atmospheric Nitrogen ◽  
Nitrogen Gas ◽  
Last Glacial Period ◽  
Temperature Changes ◽  
Core Samples ◽  
The Last Glacial

Abstract. The use of isotopic ratios of nitrogen gas (δ15N) trapped in ice cores as a paleothermometer to characterise abrupt climate changes is becoming a widespread technique. The versatility of the technique could be enhanced, for instance in quantifying small temperature changes during the last glacial period in Antarctic ice cores, by using high precision methods. In this paper, we outline a method for measuring δ15N to a precision of 0.006\\permil (1σ, n=9) from replicate ice core samples. The high precision results from removing oxygen, carbon dioxide and water vapour from the air extracted from ice cores. The advantage of the technique is that it does not involve correction for isobaric interference due to CO+ ions. We also highlight the importance of oxygen removal from the sample, and how it influences δ15N measurements. The results show that a small amount of oxygen in the sample can be detrimental to achieving an optimum precision in δ15N measurements of atmospheric nitrogen trapped ice core samples.

Comparison of northern and central Greenland ice core records of methanesulfonate covering the last glacial period

2007 ◽  
Vol 112 (D14) ◽  
Author(s):  
Ulf Jonsell ◽  
Margareta E. Hansson ◽  
Marie-Louise Siggaard-Andersen ◽  
Jørgen-Peder Steffensen
Keyword(s):  
Ice Core ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial ◽  
Ice Core Records

Synchronous timing of abrupt climate changes during the last glacial period

Science ◽  
2020 ◽  
Vol 369 (6506) ◽  
pp. 963-969
Author(s):  
Ellen C. Corrick ◽  
Russell N. Drysdale ◽  
John C. Hellstrom ◽  
Emilie Capron ◽  
Sune Olander Rasmussen ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
South American ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Independent Evidence ◽  
Last Glacial ◽  
Mediterranean Regions ◽  
Regional Synchrony ◽  
The Last Glacial

Abrupt climate changes during the last glacial period have been detected in a global array of palaeoclimate records, but our understanding of their absolute timing and regional synchrony is incomplete. Our compilation of 63 published, independently dated speleothem records shows that abrupt warmings in Greenland were associated with synchronous climate changes across the Asian Monsoon, South American Monsoon, and European-Mediterranean regions that occurred within decades. Together with the demonstration of bipolar synchrony in atmospheric response, this provides independent evidence of synchronous high-latitude–to-tropical coupling of climate changes during these abrupt warmings. Our results provide a globally coherent framework with which to validate model simulations of abrupt climate change and to constrain ice-core chronologies.

scholarly journals The anatomy of past abrupt warmings recorded in Greenland ice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
E. Capron ◽  
S. O. Rasmussen ◽  
T. J. Popp ◽  
T. Erhardt ◽  
H. Fischer ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Climate System ◽  
Data Availability ◽  
Tight Coupling ◽  
Decadal Scale ◽  
Abrupt Changes ◽  
Systematic Pattern ◽  
The Last Glacial

AbstractData availability and temporal resolution make it challenging to unravel the anatomy (duration and temporal phasing) of the Last Glacial abrupt climate changes. Here, we address these limitations by investigating the anatomy of abrupt changes using sub-decadal-scale records from Greenland ice cores. We highlight the absence of a systematic pattern in the anatomy of abrupt changes as recorded in different ice parameters. This diversity in the sequence of changes seen in ice-core data is also observed in climate parameters derived from numerical simulations which exhibit self-sustained abrupt variability arising from internal atmosphere-ice-ocean interactions. Our analysis of two ice cores shows that the diversity of abrupt warming transitions represents variability inherent to the climate system and not archive-specific noise. Our results hint that during these abrupt events, it may not be possible to infer statistically-robust leads and lags between the different components of the climate system because of their tight coupling.

scholarly journals South Pole glacial climate reconstruction from multi-borehole laser particulate stratigraphy

2013 ◽  
Vol 59 (218) ◽  
pp. 1117-1128 ◽  
Author(s):  
Keyword(s):  
Particle Physics ◽  
Volcanic Ash ◽  
Ice Core ◽  
Hot Water ◽  
Radiometric Dating ◽  
South Pole ◽  
Last Glacial Period ◽  
Annual Layer ◽  
Paleoclimate Records ◽  
The Last Glacial

AbstractThe IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around ∼74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.

scholarly journals Vostok, Antarctica, Ice Core: The Dust Record Over The Last Climatic Cycle (∼160 ka) (Abstract)

1988 ◽  
Vol 11 ◽  
pp. 204-204
Author(s):  
L. Mounier ◽  
J. R. Petit ◽  
J. Jouzel ◽  
C. Lorius ◽  
Ye. S. Korotkevich ◽  
...  
Keyword(s):  
Total Concentration ◽  
Ice Core ◽  
Ice Cores ◽  
Optical Microscope ◽  
Ice Age ◽  
Maximum Temperature ◽  
Temperature Changes ◽  
Last Glacial ◽  
Chemical Measurements ◽  
The Last Glacial

The 2083 m Vostok Antarctic ice core provides a unique opportunity for access to many paleoclimatic and paleo-environmental proxy data. This core, which has been dated by using a glaciological model, fully covers the last glacial-interglacial cycle, and goes back to the ice age which preceded the last interglaciai (−160 ka B P ).A continuous deuterium record is now available and we have interpreted it in terms of local temperature changes. This record is dominated by the large 100 ka glacial-inter-glacial oscillation, with a maximum temperature amplitude of about 11°C; the long Last Glacial period is very well documented and it is confirmed that the warmest part of the Last Interglaciai period was about 2°C warmer than the Holocene. Comparison with the ice-volume marine record shows that the Vostok climate record is of relatively large geographical significance, which makes it possible to establish, over the last 160 ka, the link between worldwide climatic changes and the Vostok dust record that we present here.This dust content corresponds to the non-soluble microparticles. It was obtained on a discontinuous basis (1 sample = about ∼10 m). Due to the very low concentration of some samples (down to 20 x 10−9gg−1) and cracks in the ice from the first 1000 m depth, we used stringent decontamination procedures. Size distribution and total concentration were measured, using a Coulter counter and an optical microscope; the results were tested against chemical measurements (aluminium concentration). In previous studies, it has been shown that the main proportion of insoluble microparticles is of terrigenous origin and represents the small-sized (radius <2 μm) dust produced on the continents.The Vostok record displays an increase in dust concentration of up to 20 times during the coldest climatic periods, coupled with the presence of larger particles. It confirms, on a much longer time-scale, a characteristic previously noted in Antarctic and Greenland ice cores over the Last Glacial Maximum. This large increase is attributed to a greater areal extent of global tropical aridity during the cold periods, coupled with higher efficiency of atmospheric circulation in respect of dust production and transport. Beyond this, the relationship between the dust input and the successive stages during the Last Glacial is now very well documented and will be discussed with a view to correlating the Vostok climatic record with other marine and terrestrial paleodata.

scholarly journals A Radiocarbon Perspective on Greenland Ice-Core Chronologies: Can we Use Ice Cores for 14C Calibration?

Radiocarbon ◽  
2004 ◽  
Vol 46 (3) ◽  
pp. 1239-1259 ◽  
Author(s):  
John Southon
Keyword(s):  
Last Glacial Maximum ◽  
Northern Hemisphere ◽  
Time Scale ◽  
Ice Core ◽  
Ice Cores ◽  
Strong Correlations ◽  
Crucial Importance ◽  
Proxy Records ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Some of the most valuable paleoclimate archives yet recovered are the multi-proxy records from the Greenland GISP2 and GRIP ice cores. The crucial importance of these data arises in part from the strong correlations that exist between the Greenland δ18O records and isotopic or other proxies in numerous other Northern Hemisphere paleoclimate sequences. These correlations could, in principle, allow layer-counted ice-core chronologies to be transferred to radiocarbon-dated paleoclimate archives, thus providing a 14C calibration for the Last Glacial Maximum and Isotope Stage 3, back to the instrumental limits of the 14C technique. However, this possibility is confounded by the existence of numerous different chronologies, as opposed to a single (or even a “best”) ice-core time scale. This paper reviews how the various chronologies were developed, summarizes the differences between them, and examines ways in which further research may allow a 14C calibration to be established.

scholarly journals Climatic Record From an Ice Margin Area in East Antarctica

1990 ◽  
Vol 14 ◽  
pp. 323-327 ◽  
Author(s):  
T.D. Yao ◽  
J.R. Petit ◽  
J. Jouzel ◽  
C. Lorius ◽  
P. Duval
Keyword(s):  
Ice Core ◽  
East Antarctica ◽  
Deuterium Content ◽  
Ice Crystal ◽  
High Concentration ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Climatic Record ◽  
Ice Crystal Size ◽  
The Last Glacial

Deuterium content, microparticle concentration, ice crystal size and bubble concentration have been studied along an 82 m ice core drilled down to the bedrock in the ice-sheet margin in East Antarctica. The Last Glacial Maximum (LGM) is distinctly marked by low deuterium content, high concentration of microparticles, small ice crystals and high bubble concentrations. This core covers a significant part of the Last Glacial Period with ice from a warmer period recovered around a depth of 60 m.

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