Chemical Evidence in Polar Ice Cores from Dielectric Profiling

The dielectric stratigraphy of a 130 m ice core from Dolleman Island, Antarctic Peninsula, shows large variations in the dielectric relaxation process and in conductivity. A comparison with the chemical stratigraphy of the core demonstrates the decisive role played by both acids and salts in determining the electrical behaviour of natural ice. The dielectric response is sensitive both to the type of impurity and to its distribution within the ice fabric. The evidence supports other observations of the localization of sulphuric acid at three-grain boundaries: in contrast, the salt impurity appears to be largely incorporated into the ice lattice. The overriding importance of the dielectric profiling technique is that it is the only profiling tool so far developed that is sensitive to the presence of salt in polar ice cores.

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Polar ice stratigraphy from laser-light scattering: scattering from meltwater

Journal of Glaciology ◽

10.1017/s0022143000012387 ◽

1994 ◽

Vol 40 (136) ◽

pp. 504-508 ◽

Cited By ~ 17

Author(s):

Michael Ram ◽

Matthias Illing

Keyword(s):

Light Scattering ◽

Sample Size ◽

Tree Ring ◽

Laser Light ◽

Ice Core ◽

Ice Cores ◽

Laser Light Scattering ◽

Polar Ice ◽

The Core ◽

Considerable Success

Abstract We describe a new laser-light-scattering instrument for measuring variations in dust concentration along polar ice cores. We have used this instrument with considerable success on the GISP2 ice core from central Greenland. Reproducibility is excellent and the required ice-sample size is relatively small. When combined with visual stratigraphy and ECM, the distinct annual spring/ summer dust peaks we observe can be used to date the core with tree-ring-like precision.

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Polar ice stratigraphy from laser-light scattering: scattering from meltwater

Journal of Glaciology ◽

10.3189/s0022143000012387 ◽

1994 ◽

Vol 40 (136) ◽

pp. 504-508

Author(s):

Michael Ram ◽

Matthias Illing

Keyword(s):

Light Scattering ◽

Sample Size ◽

Tree Ring ◽

Laser Light ◽

Ice Core ◽

Ice Cores ◽

Laser Light Scattering ◽

Polar Ice ◽

The Core ◽

Considerable Success

AbstractWe describe a new laser-light-scattering instrument for measuring variations in dust concentration along polar ice cores. We have used this instrument with considerable success on the GISP2 ice core from central Greenland. Reproducibility is excellent and the required ice-sample size is relatively small. When combined with visual stratigraphy and ECM, the distinct annual spring/ summer dust peaks we observe can be used to date the core with tree-ring-like precision.

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Differentiating bubble-free layers from melt layers in ice cores using noble gases

Journal of Glaciology ◽

10.3189/2015jog14j237 ◽

2015 ◽

Vol 61 (227) ◽

pp. 585-594 ◽

Cited By ~ 9

Author(s):

Anais J. Orsi ◽

Kenji Kawamura ◽

John M. Fegyveresi ◽

Melissa A. Headly ◽

Richard B. Alley ◽

...

Keyword(s):

Reliable Method ◽

Gas Transport ◽

Ice Core ◽

Ice Cores ◽

Gas Composition ◽

Polar Ice ◽

Clathrate Formation ◽

Ice Caps ◽

The Core ◽

Visual Identification

AbstractMelt layers are clear indicators of extreme summer warmth on polar ice caps. The visual identification of refrozen meltwater as clear bubble-free layers cannot be used to study some past warm periods, because, in deeper ice, bubbles are lost to clathrate formation. We present here a reliable method to detect melt events, based on the analysis of Kr/Ar and Xe/Ar ratios in ice cores, and apply it to the detection of melt in clathrate ice from the Eemian at NEEM, Greenland. Additionally, melt layers in ice cores can compromise the integrity of the gas record by dissolving soluble gases, or by altering gas transport in the firn, which affects the gas chronology. We find that the easily visible 1 mm thick bubble-free layers in the WAIS Divide ice core do not contain sufficient melt to alter the gas composition in the core, and do not cause artifacts or discontinuities in the gas chronology. The presence of these layers during winter, and the absence of anomalies in soluble gases, suggests that these layers can be formed by processes other than refreezing of meltwater. Consequently, the absence of bubbles in thin crusts is not in itself proof of a melt event.

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Methanesulphonic acid movement in solid ice cores

Annals of Glaciology ◽

10.3189/172756404781814645 ◽

2004 ◽

Vol 39 ◽

pp. 540-544 ◽

Cited By ~ 13

Author(s):

Barbara T. Smith ◽

Tas D. Van Ommen ◽

Mark A. J. Curran

Keyword(s):

Diffusion Coefficient ◽

Biological Activity ◽

Sea Ice ◽

Diffusion Mechanism ◽

Ice Core ◽

Ice Cores ◽

East Antarctica ◽

The Core ◽

Central Value

AbstractMethanesulphonic acid (MSA) is an important trace-ion constituent in ice cores, with connections to biological activity and sea-ice distribution. Post-depositional movement of MSA has been documented in firn, and this study investigates movement in solid ice by measuring variations in MSA distribution across several horizontal sections from an ice core after 14.5 years storage. The core used is from below the bubble close-off depth at Dome Summit South, Law Dome, East Antarctica. MSA concentration was studied at 3 and 0.5 cm resolution across the core widths. Its distribution was uniform through the core centres, but the outer 3 cm showed gradients in concentrations down to less than half of the central value at the core edge. This effect is consistent with diffusion to the surrounding air during its 14.5 year storage. The diffusion coefficient is calculated to be 2 ×10–13 m2 s–1, and the implications for the diffusion mechanism are discussed.

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Dating of ice cores from temperate glaciers - Significant mass loss in the accumulation area of the Adamello glacier indicated by the chronology of a 46 m ice core

10.5194/egusphere-egu21-7473 ◽

2021 ◽

Author(s):

Theo Jenk ◽

Daniela Festi ◽

Margit Schwikowski ◽

Valter Maggi ◽

Klaus Oeggl

Keyword(s):

Mass Loss ◽

Ice Core ◽

Ice Cores ◽

Italian Alps ◽

Accumulation Zone ◽

The Core ◽

Annual Layer ◽

Significant Mass Loss ◽

Carbon Concentrations ◽

Significant Mass

Dating glaciers is an arduous yet essential task in ice core studies, which becomes even more challenging for the dating of glaciers suffering from mass loss in the accumulation zone as result of climate warming. In this context, we present the dating of a 46 m deep ice core from the Central Italian Alps retrieved in 2016 from the Adamello glacier (Pian di Neve, 3100 m a.s.l.). We will show how the timescale for the core could be obtained by integrating results from the analyses of the radionuclides 210Pb and 137Cs with annual layer counting derived from pollen and refractory black carbon concentrations. Our results clearly indicate that the surface of the glacier is older than the drilling date of 2016 by about 20 years and that the 46 m ice core reaches back to around 1944. Despite the severe mass loss affecting this glacier even in the accumulation zone, we show that it is possible to obtain a reliable timescale for such a temperate glacier. These results are very encouraging and open new perspectives on the potential of such glaciers as informative palaeoarchives. We thus consider it important to present our dating approach to a broader audience.

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Towards radiocarbon dating of ice cores

Journal of Glaciology ◽

10.3189/002214309790794922 ◽

2009 ◽

Vol 55 (194) ◽

pp. 985-996 ◽

Cited By ~ 33

Author(s):

M. Sigl ◽

T.M. Jenk ◽

T. Kellerhals ◽

S. Szidat ◽

H.W. Gäggeler ◽

...

Keyword(s):

Aerosol Particles ◽

Ice Core ◽

Ice Cores ◽

Swiss Alps ◽

Carbonaceous Aerosol ◽

Polar Ice ◽

Low Latitude ◽

Bolivian Andes ◽

Glacier Ice ◽

Dating Method

AbstractA recently developed dating method for glacier ice, based on the analysis of radiocarbon in carbonaceous aerosol particles, is thoroughly investigated. We discuss the potential of this method to achieve a reliable dating using examples from a mid- and a low-latitude ice core. Two series of samples from Colle Gnifetti (4450 m a.s.l., Swiss Alps) and Nevado Illimani (6300 m a.s.l., Bolivian Andes) demonstrate that the 14C ages deduced from the water-insoluble organic carbon fraction represent the age of the ice. Sample sizes ranged between 7 and 100 μg carbon. For validation we compare our results with those from independent dating. This new method is thought to have major implications for dating non-polar ice cores in the future, as it provides complementary age information for time periods not accessible with common dating techniques.

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Environmental records from polar ice cores

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1990.0026 ◽

1990 ◽

Vol 330 (1615) ◽

pp. 459-462 ◽

Cited By ~ 1

Keyword(s):

Solar Activity ◽

Ice Core ◽

Ice Cores ◽

Polar Ice ◽

Cosmogenic Isotope ◽

Wide Range ◽

Recent Part ◽

Ice Core Records

Polar ice cores provide a wide range of information on past atmospheric climate (temperature, precipitation) and environment (gas and aerosol concentrations). The dating can be very accurate for the more recent part of the records but accuracy decreases with depth and time. Measurements of cosmogenic isotope concentrations (such as 10 Be) provide information on palaeo-precipitation rates and particular events can be used to correlate ice core records. Besides these climatic applications, 10 Be concentration records in ice cores also contain information on solar activity changes.

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Measurements of CO2 and CH4 concentrations in air in a polar ice core

Journal of Glaciology ◽

10.1017/s0022143000015860 ◽

1993 ◽

Vol 39 (132) ◽

pp. 209-215 ◽

Cited By ~ 21

Author(s):

Takakiyo Nakazawa ◽

Toshinobu Machida ◽

Kenji Esumi ◽

Masayuki Tanaka ◽

Yoshiyuki Fujii ◽

...

Keyword(s):

Gas Chromatography ◽

Preliminary Analysis ◽

Extraction Efficiency ◽

Ice Core ◽

Fine Powder ◽

Glacial Period ◽

Polar Ice ◽

The Core ◽

Precise Analysis ◽

Better Than

AbstractDry and wet air-extraction systems and precise analysis systems of the CO2and CH4concentrations for a polar ice core were developed to reconstruct their ancient levels. A dry-extraction system was capable of crushing an ice sample of 1000 g into fine powder within 2 min, and its air-extraction efficiency was found to be 98%. The CO2and CH4concentrations of extracted air were determined using gas chromatography with a flame-ionized detector. The overall precision of our measurements, including air extraction, was estimated to be better than ± 1 ppmv for CO2and + 10 ppbv for CH4. Preliminary analysis of the ice core drilled at Mizuho Station, Antarctica, showed that the CO2and CH4concentrations at 3340–3700 year BP were about 280 ppmv and 700ppbv, respectively. The Yamato core drilled at the terminus of the glacial flow near the Yamato Mountains, Antarctica, yielded concentrations of 230–240 ppmv for CO2and 520–550 ppbv for CH4, suggesting that the core had formed during the glacial period.

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Grain Growth in Polar Ice: II. Application

Journal of Glaciology ◽

10.1017/s0022143000012132 ◽

1986 ◽

Vol 32 (112) ◽

pp. 425-433 ◽

Cited By ~ 84

Author(s):

R.B. Alley ◽

J.H. Perepezko ◽

C.R. Bentley

Keyword(s):

Grain Boundaries ◽

Grain Growth ◽

Growth Rates ◽

Boundary Migration ◽

Ice Core ◽

Ice Cores ◽

Geometric Constraints ◽

Polar Ice ◽

High Concentration ◽

Micro Particles

AbstractGrain growth observed in polar ice that is not deforming rapidly can be accounted for if concentrations and distributions of extrinsic materials (microparticles, bubbles, and dissolved impurities) are characterized fully. Dissolved impurities segregate to grain boundaries and slow grain growth in all cold glacial ice. The high concentration of soluble impurities in Wisconsinan ice from the Dome C (Antarctica) ice core (and perhaps other ice cores) probably causes the small grain-sizes observed in that ice. Microparticles have little effect on grain growth in ordinary ice. In ice layers that appear dirty owing to concentrations of volcanic tephra (such as in the Byrd Station (Antarctica) ice core) or of morainal material, micro particles reduce grain-growth rates significantly. The relatively high vapor pressure of ice allows rapid growth and high mobility of intergranular necks, so grain growth in firn is limited by boundary migration rather than by neck growth. Bubbles formed by pore close-off at the firn-ice transition are less mobile than grain boundaries, causing bubble-boundary separation whenever geometric constraints are satisfied; however, such separation reduces grain-growth rates by only about 10%. The observed linear increase of grain area with time is thus predicted by theory, but the growth rate depends on soluble-impurity concentrations as well as on temperature.

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