New insights into the ~74 ka Toba eruption from sulfur isotopes of polar ice cores

The ~74ka Toba eruption in Indonesia was one of the largest volcanic events of the Quaternary and loaded an estimated 100 million tonnes of H2SO4 into the atmosphere. Understanding the precise timing of this colossal eruption is vital to unravelling the climatic and environmental impacts of the largest volcanic events on Earth. Sulfur aerosols injected into the stratosphere following large volcanic events scatter incoming radiation and lead to global cooling, and in the case of Toba it has been suggested that it led to cooling of 1 &#8211; 5&#176;C and extinctions of some local hominin populations. One of the most enigmatic features of the Toba eruption is that the S peak has yet to be identified in the ice core records, although numerous candidate sulfate peaks have been identified in both Arctic and Antarctic ice cores. To address this, we analysed the sulfur isotope fingerprint (&#948;34S and &#916;33S) of 11 Toba candidates from two Antarctic ice cores by multi-collector inductively coupled plasma mass spectrometry. This approach allows us to evaluate injection altitudes and to distinguish large tropical eruptions from proximal eruptions because stratospheric sulfur aerosols undergo UV photochemical reactions that impart a sulfur mass-independent isotopic fractionation (S-MIF). In contrast, tropospheric sulfur aerosols do not exhibit S-MIF because they are shielded from the relevant UV radiation by the ozone layer.We identify three stratospheric, tropical eruption candidates with two recording the largest &#916;33S signals measured to date in the ice core archives. The largest of these &#916;33S signals is >2 &#8240; more negative than previous measurements of the 1257 Samalas eruption (the largest eruption of the last 2000 years), despite having a similar integrated sulfate flux for this event to the ice core. These three candidates are within uncertainly of the Ar40/Ar39 age estimates for the Toba eruption and when considered with other paleoclimate proxies place the event during the transition into Greenland Stadial 20. &#160;Finally, we further analyse the relationship between the Toba eruption candidates and these proxies to determine the precise timing and potential climatic impacts of one of the largest eruptions of the Quaternary period.

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

10.5194/egusphere-egu2020-8537 ◽

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

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 &#8220;Oldest ice core&#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 &#8220;Oldest Ice Core&#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.

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New LA-ICP-MS cryocell and calibration technique for sub-millimeter analysis of ice cores

Journal of Glaciology ◽

10.3189/2015jog14j139 ◽

2015 ◽

Vol 61 (226) ◽

pp. 233-242 ◽

Cited By ~ 22

Author(s):

Sharon B. Sneed ◽

Paul A. Mayewski ◽

W.G. Sayre ◽

Michael J. Handley ◽

Andrei V. Kurbatov ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Chemical Constituents ◽

Ice Core ◽

Flow Analysis ◽

Ice Cores ◽

Calibration Technique ◽

Inductively Coupled ◽

Annual Layer ◽

Icp Ms ◽

Plasma Mass Spectrometry

AbstractIce cores provide a robust reconstruction of past climate. However, development of timescales by annual-layer counting, essential to detailed climate reconstruction and interpretation, on ice cores collected at low-accumulation sites or in regions of compressed ice, is problematic due to closely spaced layers. Ice-core analysis by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) provides sub-millimeter-scale sampling resolution (on the order of 100 μm in this study) and the low detection limits (ng L−1) necessary to measure the chemical constituents preserved in ice cores. We present a newly developed cryocell that can hold a 1 m long section of ice core, and an alternative strategy for calibration. Using ice-core samples from central Greenland, we demonstrate the repeatability of multiple ablation passes, highlight the improved sampling resolution, verify the calibration technique and identify annual layers in the chemical profile in a deep section of an ice core where annual layers have not previously been identified using chemistry. In addition, using sections of cores from the Swiss/Italian Alps we illustrate the relationship between Ca, Na and Fe and particle concentration and conductivity, and validate the LA-ICP-MS Ca profile through a direct comparison with continuous flow analysis results.

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Two-dimensional impurity imaging in deep Antarctic ice cores: snapshots of three climatic periods and implications for high-resolution signal interpretation

The Cryosphere ◽

10.5194/tc-15-3523-2021 ◽

2021 ◽

Vol 15 (7) ◽

pp. 3523-3538

Author(s):

Pascal Bohleber ◽

Marco Roman ◽

Martin Šala ◽

Barbara Delmonte ◽

Barbara Stenni ◽

...

Keyword(s):

Grain Boundaries ◽

Inductively Coupled Plasma ◽

Ice Core ◽

Ice Cores ◽

Polar Ice ◽

Inductively Coupled ◽

Icp Ms ◽

First Results ◽

Plasma Mass Spectrometry ◽

Fine Resolution

Abstract. Due to its micrometer-scale resolution and inherently micro-destructive nature, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is particularly suited to exploring the thin and closely spaced layers in the oldest sections of polar ice cores. Recent adaptions to the LA-ICP-MS instrumentation mean we have faster washout times allowing state-of-the-art 2-D imaging of an ice core. This new method has great potential especially when applied to the localization of impurities on the ice sample, something that is crucial, to avoiding misinterpretation of the ultra-fine-resolution signals. Here we present the first results of the application of LA-ICP-MS elemental imaging to the analysis of selected glacial and interglacial samples from the Talos Dome and EPICA Dome C ice cores from central Antarctica. The localization of impurities from both marine and terrestrial sources is discussed, with special emphasis on observing a connection with the network of grain boundaries and differences between different climatic periods. Scale-dependent image analysis shows that the spatial significance of a single line profile along the main core axis increases systematically as the imprint of the grain boundaries weakens. It is demonstrated how instrumental settings can be adapted to suit the purpose of the analysis, i.e., by either employing LA-ICP-MS to study the interplay between impurities and the ice microstructure or to investigate the extremely thin climate proxy signals in deep polar ice.

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Ice Core Science Meets Computer Vision: Challenges and Perspectives

Frontiers in Computer Science ◽

10.3389/fcomp.2021.690276 ◽

2021 ◽

Vol 3 ◽

Author(s):

Pascal Bohleber ◽

Marco Roman ◽

Carlo Barbante ◽

Sebastiano Vascon ◽

Kaleem Siddiqi ◽

...

Keyword(s):

Mass Spectrometry ◽

Computer Vision ◽

Image Analysis ◽

Laser Ablation ◽

Inductively Coupled Plasma ◽

Ice Core ◽

Ice Cores ◽

Automated Image Analysis ◽

Inductively Coupled ◽

Plasma Mass Spectrometry

Polar ice cores play a central role in studies of the earth’s climate system through natural archives. A pressing issue is the analysis of the oldest, highly thinned ice core sections, where the identification of paleoclimate signals is particularly challenging. For this, state-of-the-art imaging by laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) has the potential to be revolutionary due to its combination of micron-scale 2D chemical information with visual features. However, the quantitative study of record preservation in chemical images raises new questions that call for the expertise of the computer vision community. To illustrate this new inter-disciplinary frontier, we describe a selected set of key questions. One critical task is to assess the paleoclimate significance of single line profiles along the main core axis, which we show is a scale-dependent problem for which advanced image analysis methods are critical. Another important issue is the evaluation of post-depositional layer changes, for which the chemical images provide rich information. Accordingly, the time is ripe to begin an intensified exchange between the two scientific communities of computer vision and ice core science. The collaborative building of a new framework for investigating high-resolution chemical images with automated image analysis techniques will also benefit the already wide-spread application of laser-ablation inductively-coupled plasma mass spectrometry chemical imaging in the geosciences.

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Two-dimensional impurity imaging in deep Antarctic ice cores: Snapshots of three climatic periods and implications for high-resolution signal interpretation

10.5194/tc-2020-369 ◽

2020 ◽

Author(s):

Pascal Bohleber ◽

Marco Roman ◽

Martin Šala ◽

Barbara Delmonte ◽

Barbara Stenni ◽

...

Keyword(s):

Grain Boundaries ◽

Inductively Coupled Plasma ◽

Ice Core ◽

Ice Cores ◽

Polar Ice ◽

Inductively Coupled ◽

Icp Ms ◽

First Results ◽

Plasma Mass Spectrometry ◽

Fine Resolution

Abstract. Due to its micron-scale resolution and micro-destructiveness, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is especially suited for exploring closely spaced layers in the oldest and highly thinned sections of polar ice cores. Recent adaptions of the LA-ICP-MS technique have achieved fast washout times as the basis for introducing state-of-the-art 2D imaging to ice core analysis. This new method has great potential in its application for investigating the localization of impurities on the ice sample, crucial to avoid misinterpretation of ultra-fine resolution signals. Here first results are presented from applying LA-ICP-MS elemental imaging to selected glacial and interglacial samples of the Talos Dome and EPICA Dome C ice cores from central Antarctica. The localization of impurities with both marine and terrestrial sources is discussed, revealing generally a strong connection with the network of grain boundaries but also distinct differences among climatic periods. Scale-dependent image analysis shows that the spatial significance of a single line profile along the main core axis increases systematically as the imprint of grain boundaries weakens. With this, it is demonstrated how instrumental settings can be adapted specifically fit-for-purpose, i.e. either to employ LA-ICP-MS to study the impurity-microstructure interplay or to investigate highly thinned climate proxy signals in deep polar ice.

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Dependence of ice-core relative trace-element concentration on acidification

Journal of Glaciology ◽

10.3189/2014jog13j137 ◽

2014 ◽

Vol 60 (219) ◽

pp. 103-112 ◽

Cited By ~ 22

Author(s):

Bess G. Koffman ◽

Michael J. Handley ◽

Erich C. Osterberg ◽

Mark L. Wells ◽

Karl J. Kreutz

Keyword(s):

Trace Element ◽

Inductively Coupled Plasma ◽

Element Concentration ◽

Ice Core ◽

Ice Cores ◽

Enrichment Factors ◽

Inductively Coupled ◽

Element Concentrations ◽

Plasma Mass Spectrometry ◽

Snow Samples

AbstractTo assess the role of methodological differences on measured trace-element concentrations in ice cores, we developed an experiment to test the effects of acidification strength and time on dust dissolution using snow samples collected in West Antarctica and Alaska. We leached Antarctic samples for 3 months at room temperature using nitric acid at concentrations of 0.1, 1.0 and 10.0% (v/v). At selected intervals (20 min, 24 hours, 5 days, 14 days, 28 days, 56 days, 91 days) we analyzed 23 trace elements using inductively coupled plasma mass spectrometry. Concentrations of lithogenic elements scaled with acid strength and increased by 100–1380% in 3 months. Incongruent elemental dissolution caused significant variability in calculated crustal enrichment factors through time (factor of 1.3 (Pb) to 8.0 (Cs)). Using snow samples collected in Alaska and acidified at 1% (v/v) for 383 days, we found that the increase in lithogenic element concentration with time depends strongly on initial concentration, and varies by element (e.g. Fe linear regression slope = 1.66; r = 0.98). Our results demonstrate that relative trace-element concentrations measured in ice cores depend on the acidification method used.

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Calibrated cryo-cell UV-LA-ICPMS elemental concentrations from NGRIP ice core reveal abrupt, sub-annual variability in dust across the interstadial period GI-21.2

10.5194/tc-2016-244 ◽

2016 ◽

Author(s):

Damiano Della Lunga ◽

Wolfgang Müller ◽

Sune Olander Rasmussen ◽

Anders Svensson ◽

Paul Vallelonga

Keyword(s):

Inductively Coupled Plasma ◽

Ice Core ◽

Ice Cores ◽

Major Elements ◽

Inductively Coupled ◽

Low Concentrations ◽

Core Section ◽

Plasma Mass Spectrometry ◽

Abrupt Shifts ◽

Annual Time

Abstract. Several abrupt shifts from periods of extreme cold (Greenland stadials, GS) to relatively warmer conditions (Greenland interstadials, GI) called Dansgaard-Oeschger events are recorded in the Greenland ice cores. Using cryo-cell UV-laser-ablation inductively-coupled-plasma mass spectrometry (UV-LA-ICPMS), we analysed a 2.85 m NGRIP ice core section (~ 250 years; 2691.50–2688.65 m depth) across the transitions of GI-21.2, a short-lived interstadial prior to interstadial GI-21.1 (GI-21.2: 84.87–85.09 ka b2k). GI-21.2 is a ~ 100-year-long period with δ18O values 3–4 ‰ higher than the following ~ 200 years of stadial conditions (GS-21.2), which precede the major GI-21.1 warming. We report concentrations of "major" elements indicative of dust and/or sea salt (Na, Fe, Al, Ca, Mg) at a spatial resolution of ~ 200 μm, while maintaining detection limits in the low-ppb range, thereby achieving sub-annual time resolution even in deep NGRIP ice. We present an improved external calibration and quantification procedure using a set of five ice standards made from aqueous (international) standard solutions. Our results show that element concentrations decrease drastically (more than tenfold) at the warming onset of GI-21.2 at the scale of a single year, followed by relatively low concentrations characterizing the interstadial part before gradually reaching again typical stadial values.

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A new method of resolving annual precipitation for the past millennia from Tibetan ice cores

10.5194/tc-2021-115 ◽

2021 ◽

Author(s):

Wangbin Zhang ◽

Shugui Hou ◽

Shuang-Ye Wu ◽

Hongxi Pang ◽

Sharon B. Sneed ◽

...

Keyword(s):

High Resolution ◽

Inductively Coupled Plasma ◽

Flow Model ◽

Accumulation Rate ◽

Ice Core ◽

Ice Cores ◽

New Method ◽

Inductively Coupled ◽

Ice Cap ◽

Thinning Parameter

Abstract. Net accumulation records derived from ice cores provide the most direct measurement of past precipitation. However, quantitative reconstruction of accumulation for past millennia remains challenging due to the difficulty in identifying annual layers in the deeper sections of ice cores. In this study, we propose a new method to quantify annual accumulation from ice cores for past millennia, using as an example an ice core drilled at the Chongce ice cap in the northwestern Tibetan Plateau (TP). First, we used the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) technology to develop an ultra-high-resolution trace element records in three sections of the ice core and identified annual layers in each section based on seasonality of these elements. Second, based on nine 14C ages determined for this ice core, we developed a two-parameter flow model to established the thinning parameter of this ice core. Finally, we converted the thickness of annual layers in the three sample sections to past accumulation rates based on the thinning parameter derived from the ice-flow model. Our results show that the mean annual accumulation rate for the three sample sections are 102 mm/year (2511–2541 a B.P.), 76 mm/year (1682–1697 a B.P.) and 84 mm/year (781–789 a B.P.). For comparison, the Holocene mean precipitation is 103 mm/year. This method has the potential to reconstruct continuous high-resolution precipitation records covering millennia or even longer time periods.

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Calibrated cryo-cell UV-LA-ICPMS elemental concentrations from the NGRIP ice core reveal abrupt, sub-annual variability in dust across the GI-21.2 interstadial period

The Cryosphere ◽

10.5194/tc-11-1297-2017 ◽

2017 ◽

Vol 11 (3) ◽

pp. 1297-1309 ◽

Cited By ~ 5

Author(s):

Damiano Della Lunga ◽

Wolfgang Müller ◽

Sune Olander Rasmussen ◽

Anders Svensson ◽

Paul Vallelonga

Keyword(s):

Inductively Coupled Plasma ◽

Ice Core ◽

Ice Cores ◽

Major Elements ◽

Inductively Coupled ◽

Low Concentrations ◽

Core Section ◽

Plasma Mass Spectrometry ◽

Abrupt Shifts ◽

Annual Time

Abstract. Several abrupt shifts from periods of extreme cold (Greenland stadials, GS) to relatively warmer conditions (Greenland interstadials, GI) called Dansgaard–Oeschger events are recorded in the Greenland ice cores. Using cryo-cell UV-laser-ablation inductively coupled-plasma mass spectrometry (UV-LA-ICPMS), we analysed a 2.85 m NGRIP ice core section (2691.50–2688.65 m depth, age interval 84.86–85.09 ka b2k, thus covering ∼  230 years) across the transitions of GI-21.2, a short-lived interstadial prior to interstadial GI-21.1. GI-21.2 is a ∼  100-year long period with δ18O values 3–4 ‰ higher than the following ∼  200 years of stadial conditions (GS-21.2), which precede the major GI-21.1 warming. We report concentrations of major elements indicative of dust and/or sea salt (Na, Fe, Al, Ca, Mg) at a spatial resolution of ∼  200 µm, while maintaining detection limits in the low-ppb range, thereby achieving sub-annual time resolution even in deep NGRIP ice. We present an improved external calibration and quantification procedure using a set of five ice standards made from aqueous (international) standard solutions. Our results show that element concentrations decrease drastically (more than 10-fold) at the warming onset of GI-21.2 at the scale of a single year, followed by relatively low concentrations characterizing the interstadial part before gradually reaching again typical stadial values.

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