scholarly journals An improved North-South synchronization of ice core records around the 41 K beryllium 10 peak

2016 ◽  
Author(s):  
G. M. Raisbeck ◽  
A. Cauquoin ◽  
J. Jouzel ◽  
A. Landais ◽  
J.-R. Petit ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Properties ◽  
Ice Core ◽  
Ice Cores ◽  
Published Data ◽  
Geomagnetic Excursion ◽  
Depth Difference ◽  
Order Of Magnitude ◽  
The Difference ◽  
Better Than

Abstract. Abstract. Using new high resolution 10Be measurements in the NGRIP, EDML and Vostok ice cores, together with previously published data from EDC, we present an improved synchronization between Greenland and Antarctic ice cores during the Laschamp geomagnetic excursion ~ 41 ky ago. We estimate the precision of this synchronization to be ± 20 years, an order of magnitude better than our previous work. We discuss the implications of this new synchronization for making improved estimates of the difference between ice and enclosed gas of the same age (delta depth), difference between age of ice and enclosed gas at the same depth (delta age) in the EDC and EDML ice cores, spectral properties of the 10Be profiles and phasing between Dansgaard/Oeschger-10 (in NGRIP) and AIM-10 (in EDML and EDC).

scholarly journals An improved north–south synchronization of ice core records around the 41 kyr <sup>10</sup>Be peak

2017 ◽  
Vol 13 (3) ◽  
pp. 217-229 ◽  
Author(s):  
Grant M. Raisbeck ◽  
Alexandre Cauquoin ◽  
Jean Jouzel ◽  
Amaelle Landais ◽  
Jean-Robert Petit ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Properties ◽  
Ice Core ◽  
Ice Cores ◽  
Published Data ◽  
Geomagnetic Excursion ◽  
Depth Difference ◽  
Order Of Magnitude ◽  
Better Than ◽  
Ice Core Records

Abstract. Using new high-resolution 10Be measurements in the NGRIP, EDML and Vostok ice cores, together with previously published data from EDC, we present an improved synchronization between Greenland and Antarctic ice cores during the Laschamp geomagnetic excursion  ∼  41 kyr ago. We estimate the precision of this synchronization to be ±20 years, an order of magnitude better than previous work. We discuss the implications of this new synchronization for making improved estimates of the depth difference between ice and enclosed gas of the same age (Δdepth), difference between age of ice and enclosed gas at the same depth (Δage) in the EDC and EDML ice cores, spectral properties of the 10Be profiles and phasing between Dansgaard–Oeschger-10 (in NGRIP) and AIM-10 (in EDML and EDC).

Tephra in the Greenland Ice cores: Insights into Icelandic volcano-climate impacts

2021 ◽  
Author(s):  
Imogen Gabriel ◽  
Gill Plunkett ◽  
Peter Abbott ◽  
Bergrún Óladóttir ◽  
Joseph McConnell ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Climate Impacts ◽  
Geochemical Analysis ◽  
Volcanic Events ◽  
Societal Impacts ◽  
The Impact ◽  
Ice Core Records

&lt;p&gt;Volcanic eruptions are considered as one of the primary natural drivers for changes in the global climate system and understanding the impact of past eruptions on the climate is integral to adopt appropriate responses towards future volcanic eruptions.&lt;/p&gt;&lt;p&gt;The Greenland ice core records are dominated by Icelandic eruptions, with several volcanic systems (Katla, Hekla, B&amp;#225;r&amp;#240;arbunga-Vei&amp;#240;iv&amp;#246;tn and Grimsv&amp;#246;tn) being highly active throughout the Holocene. A notable period of increased Icelandic volcanic activity occurred between 500-1250 AD and coincided with climatic changes in the North Atlantic region which may have facilitated the Viking settlement of Greenland and Iceland. However, a number of these volcanic events are poorly constrained (duration and magnitude). Consequently, the Greenland ice cores offer the opportunity to reliably reconstruct past Icelandic volcanism (duration, magnitude and frequency) due to their high-resolution, the proximity of Iceland to Greenland and subsequent increased likelihood of volcanic fallout deposits (tephra particles and sulphur aerosols) being preserved. However, both the high frequency of eruptions between 500-1250 AD and the geochemical similarity of Iceland&amp;#8217;s volcanic centres present challenges in making the required robust geochemical correlations between the source volcano and the ice core records and ultimately reliably assessing the climatic-societal impacts of these eruptions.&lt;/p&gt;&lt;p&gt;To address this, we use two Greenland ice core records (TUNU2013 and B19) and undertake geochemical analysis on tephra from the volcanic events in the selected time window which have been detected and sampled using novel techniques (insoluble particle peaks and sulphur acidity peaks). Further geochemical analysis of proximal material enables robust correlations to be made between the events in the ice core records and their volcanic centres. The high-resolution of these polar archives provides a precise age for the event and when utilised alongside other proxies (i.e. sulphur aerosols), both the duration and magnitude of these eruptions can be constrained, and the climatic-societal impacts of these eruptions reliably assessed.&lt;/p&gt;

scholarly journals The magnitude and impact of the 431 CE Tierra Blanca Joven eruption of Ilopango, El Salvador

2020 ◽  
Vol 117 (42) ◽  
pp. 26061-26068 ◽  
Author(s):  
Victoria C. Smith ◽  
Antonio Costa ◽  
Gerardo Aguirre-Díaz ◽  
Dario Pedrazzi ◽  
Andrea Scifo ◽  
...  
Keyword(s):  
High Resolution ◽  
El Salvador ◽  
Central America ◽  
State Of The Art ◽  
Ice Core ◽  
Ice Cores ◽  
Ash Layer ◽  
Ice Core Record ◽  
Climatic Impacts ◽  
Eruption Magnitude

The Tierra Blanca Joven (TBJ) eruption from Ilopango volcano deposited thick ash over much of El Salvador when it was inhabited by the Maya, and rendered all areas within at least 80 km of the volcano uninhabitable for years to decades after the eruption. Nonetheless, the more widespread environmental and climatic impacts of this large eruption are not well known because the eruption magnitude and date are not well constrained. In this multifaceted study we have resolved the date of the eruption to 431 ± 2 CE by identifying the ash layer in a well-dated, high-resolution Greenland ice-core record that is >7,000 km from Ilopango; and calculated that between 37 and 82 km3of magma was dispersed from an eruption coignimbrite column that rose to ∼45 km by modeling the deposit thickness using state-of-the-art tephra dispersal methods. Sulfate records from an array of ice cores suggest stratospheric injection of 14 ± 2 Tg S associated with the TBJ eruption, exceeding those of the historic eruption of Pinatubo in 1991. Based on these estimates it is likely that the TBJ eruption produced a cooling of around 0.5 °C for a few years after the eruption. The modeled dispersal and higher sulfate concentrations recorded in Antarctic ice cores imply that the cooling would have been more pronounced in the Southern Hemisphere. The new date confirms the eruption occurred within the Early Classic phase when Maya expanded across Central America.

scholarly journals Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. (∼660 BC)

2019 ◽  
Vol 116 (13) ◽  
pp. 5961-5966 ◽  
Author(s):  
Paschal O’Hare ◽  
Florian Mekhaldi ◽  
Florian Adolphi ◽  
Grant Raisbeck ◽  
Ala Aldahan ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Solar Proton ◽  
Solar Proton Event ◽  
Proton Event ◽  
Production Rates ◽  
Cosmogenic Radionuclides ◽  
Solar Event ◽  
Carbon 14 ◽  
Order Of Magnitude

Recently, it has been confirmed that extreme solar proton events can lead to significantly increased atmospheric production rates of cosmogenic radionuclides. Evidence of such events is recorded in annually resolved natural archives, such as tree rings [carbon-14 (14C)] and ice cores [beryllium-10 (10Be), chlorine-36 (36Cl)]. Here, we show evidence for an extreme solar event around 2,610 years B.P. (∼660 BC) based on high-resolution10Be data from two Greenland ice cores. Our conclusions are supported by modeled14C production rates for the same period. Using existing36Cl ice core data in conjunction with10Be, we further show that this solar event was characterized by a very hard energy spectrum. These results indicate that the 2,610-years B.P. event was an order of magnitude stronger than any solar event recorded during the instrumental period and comparable with the solar proton event of AD 774/775, the largest solar event known to date. The results illustrate the importance of multiple ice core radionuclide measurements for the reliable identification of short-term production rate increases and the assessment of their origins.

scholarly journals Apparent discrepancy of Tibetan ice core <i>δ</i><sup>18</sup>O records may be attributed to misinterpretation of chronology

2019 ◽  
Vol 13 (6) ◽  
pp. 1743-1752 ◽  
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Hongxi Pang ◽  
Shuang-Ye Wu ◽  
Theo M. Jenk ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Apparent Discrepancy ◽  
Ice Cap ◽  
Guliya Ice Core ◽  
Cooling Trend ◽  
Instrumental Period

Abstract. Ice cores from the Tibetan Plateau (TP) are widely used for reconstructing past climatic and environmental conditions that extend beyond the instrumental period. However, challenges in dating and interpreting ice core records often lead to inconsistent results. The Guliya ice core drilled from the northwestern TP suggested a cooling trend during the mid-Holocene based on its decreasing δ18O values, which is not observed in other Tibetan ice cores. Here we present a new high-resolution δ18O record of the Chongce ice cores drilled to bedrock ∼30 km away from the Guliya ice cap. Our record shows a warming trend during the mid-Holocene. Based on our results as well as previously published ice core data, we suggest that the apparent discrepancy between the Holocene δ18O records of the Guliya and the Chongce ice cores may be attributed to a possible misinterpretation of the Guliya ice core chronology.

First continuous high-resolution aerosol record from the East Greenland Ice Core Project (EGRIP), covering the last 15,000 years

2020 ◽  
Author(s):  
Camilla Marie Jensen ◽  
Tobias Erhardt ◽  
Giulia Sinnl ◽  
Hubertus Fischer
Keyword(s):  
High Resolution ◽  
Biomass Burning ◽  
Forest Fires ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Background Level ◽  
Volcanic Eruptions ◽  
Atmospheric Conditions ◽  
Data Set

&lt;p&gt;Ice sheets are reliable archives of atmospheric impurities such as aerosols and gasses of both natural and anthropogenic origin. Impurity records from Greenland ice cores reveal much information about previous atmospheric conditions and long-range transport in the Northern hemisphere going back more than a hundred thousand years.&lt;/p&gt;&lt;p&gt;Here we present the data from the upper 1,411 m from the EGRIP ice core, measuring conductivity, dust, sodium, calcium, ammonium, and nitrate. These records contain information about ocean sources, transport of terrestrial dust, soil and vegetation emissions as well as biomass burning, volcanic eruptions, etc., covering approximately the past 15,000 years. This newly obtained data set is unique as it provides the first high-resolution information about several thousands of years of the mid-Holocene period in Greenland that none of the previous impurity records from the other deep Greenland ice cores had managed to cover before due to brittle ice. This will contribute to further understanding of the atmospheric conditions for the pre-industrial period.&lt;/p&gt;&lt;p&gt;The ammonium record contains peaks significantly higher than the background level. These peaks are caused by biomass burning or forest fires emitting plumes of ammonia large enough so that they can extend to the free troposphere and be efficiently transported all the way to the Greenland ice sheet. Here we present preliminary results of the wild fire frequency covering the entire Holocene, where the wild fires are defined as outliers in the ammonium record of annual means.&lt;/p&gt;

Towards an improved understanding of high-resolution impurity signals in deep Antarctic ice cores

2020 ◽  
Author(s):  
Pascal Bohleber ◽  
Marco Roman ◽  
Carlo Barbante ◽  
Barbara Stenni ◽  
Barbara Delmonte
Keyword(s):  
Laser Ablation ◽  
High Resolution ◽  
Inductively Coupled Plasma ◽  
Ice Core ◽  
Ice Cores ◽  
Inductively Coupled ◽  
Icp Ms ◽  
First Results ◽  
Plasma Mass Spectrometry ◽  
Fine Resolution

&lt;p&gt;Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers minimally destructive ice core impurity analysis at micron-scale resolution. This technique is especially suited for exploring closely spaced layers of ice within samples collected at low accumulation sites or in regions of highly compressed and thinned ice. Accordingly, LA-ICP-MS promises invaluable insights in the analysis of a future &amp;#8220;Oldest ice core&amp;#8221; from Antarctica. However, in contrast to ice core melting techniques, taking into account the location of impurities is crucial to avoid misinterpretation of ultra-fine resolution signals obtained from newly emerging laser ablation technologies. Here we present first results from a new LA-ICP-MS setup developed at the University of Venice, based on a customized two-volume cryogenic ablation chamber optimized for fast wash-out times. We apply our method for high-resolution chemical imagining analysis of impurities in samples from intermediate and deep sections of the Talos Dome and EPICA Dome C ice cores. We discuss the localization of both soluble and insoluble impurities within the ice matrix and evaluate the spatial significance of a single profile along the main core axis. With this, we aim at establishing a firm basis for a future deployment of the LA-ICP-MS in an &amp;#8220;Oldest Ice Core&amp;#8221;. Moreover, our work illustrates how LA-ICP-MS may offer new means to study the impurity-microstructure interplay in deep polar ice, thereby promising to advance our understanding of these fundamental processes.&lt;/p&gt;

scholarly journals Dating of Greenland Ice Cores by Flow Models, Isotopes, Volcanic Debris, and Continental Dust

1978 ◽  
Vol 20 (82) ◽  
pp. 3-26 ◽  
Author(s):  
C.U. Hammer ◽  
H. B. Clausen ◽  
W. Dansgaard ◽  
N. Gundestrup ◽  
S. J. Johnsen ◽  
...  
Keyword(s):  
Ice Core ◽  
Radioactive Decay ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Flow Models ◽  
Annual Layer ◽  
Electrical Conductivities ◽  
Volcanic Debris ◽  
Thickness Measurements ◽  
Better Than

AbstractThe available methods for dating of ice cores are based on radioactive decay, ice-flow calculations, or stratigraphic observations. The two former categories are broadly outlined, and special emphasis is given to stratigraphic methods. Reference horizons are established back to A.D. 1783, in the form of elevated electrical conductivities due to fallout of soluble volcanic debris. Seasonal variations in the concentrations of insoluble microparticles and/or stable isotopes are measured over the entire 400 m lengths of three ice cores, recovered by Greenland Ice Sheet Program (GISP). The resulting absolute time scales are probably accurate within a few years per thousand. Techniques are outlined for re-establishing the approximate, original shape of heavy-isotope profiles that have been more or less smoothed by diffusion in firn and ice. Annual-layer thickness measurements on 24 increments down to 1130 m depth in the Camp Century ice core determine a flow pattern, consistent with that suggested by Dansgaard and Johnsen (1969), and a Camp Century time scale with an estimated uncertainty better than 3% back to 10000 years B.P.

scholarly journals A 200 year sub-annual record of sulfate in West Antarctica, from 16 ice cores

2004 ◽  
Vol 39 ◽  
pp. 545-556 ◽  
Author(s):  
Daniel Dixon ◽  
Paul A. Mayewski ◽  
Susan Kaspari ◽  
Sharon Sneed ◽  
Mike Handley
Keyword(s):  
Ice Core ◽  
Temporal Distribution ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Global Scale ◽  
West Antarctica ◽  
West Antarctic ◽  
Volcanic Events ◽  
Climate Transition ◽  
Better Than

AbstractSixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO42– and excess (xs) SO42– is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000 m. Our xsSO42– records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO42– concentrations but do reveal that a major climate transition takes place over West Antarctica at ∼1940. Global-scale volcanic eruptions appear as significant peaks in the robust-spline residual xsSO42– records from sites located above 1000m elevation but do not appear in the residual records from sites located below 1000 m.

scholarly journals Fabric measurement along the NEEM ice core, Greenland, and comparison with GRIP and NGRIP ice cores

2014 ◽  
Vol 8 (1) ◽  
pp. 307-335 ◽  
Author(s):  
M. Montagnat ◽  
N. Azuma ◽  
D. Dahl-Jensen ◽  
J. Eichler ◽  
S. Fujita ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Deformation Pattern ◽  
Bottom Part ◽  
Single Maximum ◽  
Shear Component ◽  
Climatic Transition ◽  
The Difference ◽  
The Impact ◽  
Good Agreement

Abstract. Fabric (distribution of crystallographic orientations) profile along the full NEEM ice core, Greenland, is presented in this work. Data were measured in the field by an Automatic Ice Texture Analyzer every 10 m, from 33 m down to 2461 m depth. The fabric evolves from a slightly anisotropic fabric at the top, toward a strong single maximum at about 2300 m, which is typical of a deformation pattern mostly driven by uniaxial compression and simple shearing. A sharp increase in the fabric strengthening is observed at the Holocene to Wisconsin climatic transition. A similar strengthening, toward an anisotropic single maximum-type fabric, has been observed in several ice cores from Greenland and Antarctica, and can be attributed to a positive feedback between changes in ice viscosity at the climatic transition, and the impact of a shear component of stress. Centimeter scale abrupt texture (fabric and microstructure) variations are observed in the bottom part of the core. Their positions are in good agreement with the folding hypothesis used for a climatic reconstruction by Dahl-Jensen et al. (2013). Comparison is made to two others ice cores drilled along the same ridge; the GRIP ice core drilled at the summit of the ice sheet, and the NorthGRIP ice core, drilled 325 km to the NNW of the summit along the ridge, and 365 km upstream from NEEM. The fabric profile clearly reflects the increase in shear deformation when moving NW along the ridge from GRIP to NorthGRIP and NEEM. The difference in fabric profiles between NEEM and NorthGRIP also evidences a stronger lateral extension associated with a sharper ridge at NorthGRIP.

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