Articles | Volume 8, issue 5
https://doi.org/10.5194/se-8-883-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Special issue:
https://doi.org/10.5194/se-8-883-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
06 Sep 2017
Research article |
| 06 Sep 2017
EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Alten
Hafen 26, 27568 Bremerhaven, Germany
Ernst-Jan N. Kuiper
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Alten
Hafen 26, 27568 Bremerhaven, Germany
Faculty of Earth Science, Utrecht University, Postbus 80021, 3508 TA
Utrecht, the Netherlands
Gill M. Pennock
Faculty of Earth Science, Utrecht University, Postbus 80021, 3508 TA
Utrecht, the Netherlands
Sepp Kipfstuhl
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Alten
Hafen 26, 27568 Bremerhaven, Germany
Martyn R. Drury
Faculty of Earth Science, Utrecht University, Postbus 80021, 3508 TA
Utrecht, the Netherlands
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The flow of glaciers and ice streams is influenced by crystal fabric orientation. Besides sparse ice cores, these can be investigated by radar measurements. Here, we present an improved method which allows us to infer the horizontal fabric asymmetry using polarimetric phase-sensitive radar data. A validation of the method on a deep ice core from the Greenland Ice Sheet shows an excellent agreement, which is a large improvement over previously used methods.
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Polar ice is formed by ice crystals, which form fabrics that are utilised to interpret how ice sheets flow. It is unclear whether fabrics result from the current flow regime or if they are inherited. To understand the extent to which ice crystals can be reoriented when ice flow conditions change, we simulate and evaluate multi-stage ice flow scenarios according to natural cases. We find that second deformation regimes normally overprint inherited fabrics, with a range of transitional fabrics.
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In this study, we analyse whether ultrasonic measurements on ice core samples could be employed to derive information about the particular ice crystal orientation in these samples. We discuss if such ultrasonic scans of ice core samples could provide similarly detailed results as the established methods, which usually destroy the ice samples. Our geophysical approach is minimally invasive and could support the existing methods with additional and (semi-)continuous data points along the ice core.
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The Cryosphere, 11, 1075–1090, https://doi.org/10.5194/tc-11-1075-2017, https://doi.org/10.5194/tc-11-1075-2017, 2017
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The Cryosphere, 10, 3071–3089, https://doi.org/10.5194/tc-10-3071-2016, https://doi.org/10.5194/tc-10-3071-2016, 2016
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How glaciers or ice sheets flow is a result of microscopic processes controlled by the properties of individual ice crystals. We performed computer simulations on these processes and the effect of air bubbles between crystals. The simulations show that small-scale ice deformation is locally stronger than in other regions, which is enhanced by bubbles. This causes the ice crystals to recrystallise and change their properties in a way that potentially also affects the large-scale flow properties.
D. Jansen, M.-G. Llorens, J. Westhoff, F. Steinbach, S. Kipfstuhl, P. D. Bons, A. Griera, and I. Weikusat
The Cryosphere, 10, 359–370, https://doi.org/10.5194/tc-10-359-2016, https://doi.org/10.5194/tc-10-359-2016, 2016
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In this study we present examples of typical small-scale folds observed in the NEEM ice core, North Greenland, and discuss their characteristics. Numerical modelling of viscoplastic deformation and dynamic recrystallisation was used to improve the understanding of the formation of the observed structures under simple shear boundary conditions. We conclude that the folds originate from bands of grains with a tilted lattice relative to the strong lattice preferred orientation below 1500 m depth.
A. Diez, O. Eisen, C. Hofstede, A. Lambrecht, C. Mayer, H. Miller, D. Steinhage, T. Binder, and I. Weikusat
The Cryosphere, 9, 385–398, https://doi.org/10.5194/tc-9-385-2015, https://doi.org/10.5194/tc-9-385-2015, 2015
M. Montagnat, N. Azuma, D. Dahl-Jensen, J. Eichler, S. Fujita, F. Gillet-Chaulet, S. Kipfstuhl, D. Samyn, A. Svensson, and I. Weikusat
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Nicolas Stoll, Ilka Weikusat, Daniela Jansen, Paul Bons, Kyra Darányi, Julien Westhoff, Mária-Gema Llorens, David Wallis, Jan Eichler, Tomotaka Saruya, Tomoyuki Homma, Martyn Drury, Frank Wilhelms, Sepp Kipfstuhl, Dorthe Dahl-Jensen, and Johanna Kerch
EGUsphere, https://doi.org/10.5194/egusphere-2024-2653, https://doi.org/10.5194/egusphere-2024-2653, 2024
Short summary
Short summary
A better understanding of ice flow requires more observational data. The EastGRIP core is the first ice core through an active ice stream. We discuss crystal orientation data to determine the present deformation regimes. A comparison with other deep ice cores shows the unique properties of EastGRIP and that deep ice originates from the Eemian. We further show that the overall plug flow of NEGIS is characterised by many small-scale variations, which remain to be considered in ice-flow models.
Julien Westhoff, Johannes Freitag, Anaïs Orsi, Patricia Martinerie, Ilka Weikusat, Michael Dyonisius, Xavier Faïn, Kevin Fourteau, and Thomas Blunier
The Cryosphere, 18, 4379–4397, https://doi.org/10.5194/tc-18-4379-2024, https://doi.org/10.5194/tc-18-4379-2024, 2024
Short summary
Short summary
We study the EastGRIP area, Greenland, in detail with traditional and novel techniques. Due to the compaction of the ice, at a certain depth, atmospheric gases can no longer exchange, and the atmosphere is trapped in air bubbles in the ice. We find this depth by pumping air from a borehole, modeling, and using a new technique based on the optical appearance of the ice. Our results suggest that the close-off depth lies at around 58–61 m depth and more precisely at 58.3 m depth.
Sune Olander Rasmussen, Dorthe Dahl-Jensen, Hubertus Fischer, Katrin Fuhrer, Steffen Bo Hansen, Margareta Hansson, Christine S. Hvidberg, Ulf Jonsell, Sepp Kipfstuhl, Urs Ruth, Jakob Schwander, Marie-Louise Siggaard-Andersen, Giulia Sinnl, Jørgen Peder Steffensen, Anders M. Svensson, and Bo M. Vinther
Earth Syst. Sci. Data, 15, 3351–3364, https://doi.org/10.5194/essd-15-3351-2023, https://doi.org/10.5194/essd-15-3351-2023, 2023
Short summary
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Timescales are essential for interpreting palaeoclimate data. The data series presented here were used for annual-layer identification when constructing the timescales named the Greenland Ice-Core Chronology 2005 (GICC05) and the revised version GICC21. Hopefully, these high-resolution data sets will be useful also for other purposes.
Nicolas Stoll, Julien Westhoff, Pascal Bohleber, Anders Svensson, Dorthe Dahl-Jensen, Carlo Barbante, and Ilka Weikusat
The Cryosphere, 17, 2021–2043, https://doi.org/10.5194/tc-17-2021-2023, https://doi.org/10.5194/tc-17-2021-2023, 2023
Short summary
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Impurities in polar ice play a role regarding its climate signal and internal deformation. We bridge different scales using different methods to investigate ice from the Last Glacial Period derived from the EGRIP ice core in Greenland. We characterise different types of cloudy bands, i.e. frequently occurring milky layers in the ice, and analyse their chemistry with Raman spectroscopy and 2D imaging. We derive new insights into impurity localisation and deposition conditions.
Romilly Harris Stuart, Anne-Katrine Faber, Sonja Wahl, Maria Hörhold, Sepp Kipfstuhl, Kristian Vasskog, Melanie Behrens, Alexandra M. Zuhr, and Hans Christian Steen-Larsen
The Cryosphere, 17, 1185–1204, https://doi.org/10.5194/tc-17-1185-2023, https://doi.org/10.5194/tc-17-1185-2023, 2023
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This empirical study uses continuous daily measurements from the Greenland Ice Sheet to document changes in surface snow properties. Consistent changes in snow isotopic composition are observed in the absence of deposition due to surface processes, indicating the isotopic signal of deposited precipitation is not always preserved. Our observations have potential implications for the interpretation of water isotopes in ice cores – historically assumed to reflect isotopic composition at deposition.
Ole Zeising, Tamara Annina Gerber, Olaf Eisen, M. Reza Ershadi, Nicolas Stoll, Ilka Weikusat, and Angelika Humbert
The Cryosphere, 17, 1097–1105, https://doi.org/10.5194/tc-17-1097-2023, https://doi.org/10.5194/tc-17-1097-2023, 2023
Short summary
Short summary
The flow of glaciers and ice streams is influenced by crystal fabric orientation. Besides sparse ice cores, these can be investigated by radar measurements. Here, we present an improved method which allows us to infer the horizontal fabric asymmetry using polarimetric phase-sensitive radar data. A validation of the method on a deep ice core from the Greenland Ice Sheet shows an excellent agreement, which is a large improvement over previously used methods.
Maria-Gema Llorens, Albert Griera, Paul D. Bons, Ilka Weikusat, David J. Prior, Enrique Gomez-Rivas, Tamara de Riese, Ivone Jimenez-Munt, Daniel García-Castellanos, and Ricardo A. Lebensohn
The Cryosphere, 16, 2009–2024, https://doi.org/10.5194/tc-16-2009-2022, https://doi.org/10.5194/tc-16-2009-2022, 2022
Short summary
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Polar ice is formed by ice crystals, which form fabrics that are utilised to interpret how ice sheets flow. It is unclear whether fabrics result from the current flow regime or if they are inherited. To understand the extent to which ice crystals can be reoriented when ice flow conditions change, we simulate and evaluate multi-stage ice flow scenarios according to natural cases. We find that second deformation regimes normally overprint inherited fabrics, with a range of transitional fabrics.
Julien Westhoff, Giulia Sinnl, Anders Svensson, Johannes Freitag, Helle Astrid Kjær, Paul Vallelonga, Bo Vinther, Sepp Kipfstuhl, Dorthe Dahl-Jensen, and Ilka Weikusat
Clim. Past, 18, 1011–1034, https://doi.org/10.5194/cp-18-1011-2022, https://doi.org/10.5194/cp-18-1011-2022, 2022
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We present a melt event record from an ice core from central Greenland, which covers the past 10 000 years. Our record displays warm summer events, which can be used to enhance our understanding of the past climate. We compare our data to anomalies in tree ring width, which also represents summer temperatures, and find a good correlation. Furthermore, we investigate an outstandingly warm event in the year 986 AD or 991 AD, which has not been analyzed before.
Nicolas Stoll, Maria Hörhold, Tobias Erhardt, Jan Eichler, Camilla Jensen, and Ilka Weikusat
The Cryosphere, 16, 667–688, https://doi.org/10.5194/tc-16-667-2022, https://doi.org/10.5194/tc-16-667-2022, 2022
Short summary
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We mapped and analysed solid inclusion in the upper 1340 m of the EGRIP ice core with Raman spectroscopy and microstructure mapping, based on bulk dust content derived via continuous flow analysis. We observe a large variety in mineralogy throughout the core and samples. The main minerals are sulfates, especially gypsum, and terrestrial dust minerals, such as quartz, mica, and feldspar. A change in mineralogy occurs around 900 m depth indicating a climate-related imprint.
Steven Franke, Daniela Jansen, Tobias Binder, John D. Paden, Nils Dörr, Tamara A. Gerber, Heinrich Miller, Dorthe Dahl-Jensen, Veit Helm, Daniel Steinhage, Ilka Weikusat, Frank Wilhelms, and Olaf Eisen
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Short summary
Short summary
The Northeast Greenland Ice Stream (NEGIS) is the largest ice stream in Greenland. In order to better understand the past and future dynamics of the NEGIS, we present a high-resolution airborne radar data set (EGRIP-NOR-2018) for the onset region of the NEGIS. The survey area is centered at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP), and radar profiles cover both shear margins and are aligned parallel to several flow lines.
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The Cryosphere, 15, 5717–5737, https://doi.org/10.5194/tc-15-5717-2021, https://doi.org/10.5194/tc-15-5717-2021, 2021
Short summary
Short summary
We did a systematic analysis of the location of inclusions in the EGRIP ice core, the first ice core from an ice stream. We combine this with crystal orientation and grain size data, enabling the first overview about the microstructure of this unique ice core. Micro-inclusions show a strong spatial variability and patterns (clusters or horizontal layers); roughly one-third is located at grain boundaries. More holistic approaches are needed to understand deformation processes in the ice better.
Laura Crick, Andrea Burke, William Hutchison, Mika Kohno, Kathryn A. Moore, Joel Savarino, Emily A. Doyle, Sue Mahony, Sepp Kipfstuhl, James W. B. Rae, Robert C. J. Steele, R. Stephen J. Sparks, and Eric W. Wolff
Clim. Past, 17, 2119–2137, https://doi.org/10.5194/cp-17-2119-2021, https://doi.org/10.5194/cp-17-2119-2021, 2021
Short summary
Short summary
The ~ 74 ka eruption of Toba was one of the largest eruptions of the last 100 ka. We have measured the sulfur isotopic composition for 11 Toba eruption candidates in two Antarctic ice cores. Sulfur isotopes allow us to distinguish between large eruptions that have erupted material into the stratosphere and smaller ones that reach lower altitudes. Using this we have identified the events most likely to be Toba and place the eruption on the transition into a cold period in the Northern Hemisphere.
Valentin Basch, Martyn R. Drury, Oliver Plumper, Eric Hellebrand, Laura Crispini, Fabrice Barou, Marguerite Godard, and Elisabetta Rampone
Eur. J. Mineral., 33, 463–477, https://doi.org/10.5194/ejm-33-463-2021, https://doi.org/10.5194/ejm-33-463-2021, 2021
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This paper investigates the possibility for melts to migrate within extensively deformed crystals and assesses the impact of this intracrystalline melt percolation on the chemical composition of the deformed crystal. We here document that the presence of melt within a crystal greatly enhances chemical diffusive re-equilibration between the percolating melt and the mineral and that such a process occurring at crystal scale can impact the large-scale composition of the oceanic lithosphere.
Helle Astrid Kjær, Lisa Lolk Hauge, Marius Simonsen, Zurine Yoldi, Iben Koldtoft, Maria Hörhold, Johannes Freitag, Sepp Kipfstuhl, Anders Svensson, and Paul Vallelonga
The Cryosphere, 15, 3719–3730, https://doi.org/10.5194/tc-15-3719-2021, https://doi.org/10.5194/tc-15-3719-2021, 2021
Short summary
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Ice core analyses are often done in home laboratories after costly transport of samples from the field. This limits the amount of sample that can be analysed.
Here, we present the first truly field-portable continuous flow analysis (CFA) system for the analysis of impurities in snow, firn and ice cores while still in the field: the lightweight in situ analysis (LISA) box.
LISA is demonstrated in Greenland to reconstruct accumulation, conductivity and peroxide in snow cores.
Sebastian Hellmann, Melchior Grab, Johanna Kerch, Henning Löwe, Andreas Bauder, Ilka Weikusat, and Hansruedi Maurer
The Cryosphere, 15, 3507–3521, https://doi.org/10.5194/tc-15-3507-2021, https://doi.org/10.5194/tc-15-3507-2021, 2021
Short summary
Short summary
In this study, we analyse whether ultrasonic measurements on ice core samples could be employed to derive information about the particular ice crystal orientation in these samples. We discuss if such ultrasonic scans of ice core samples could provide similarly detailed results as the established methods, which usually destroy the ice samples. Our geophysical approach is minimally invasive and could support the existing methods with additional and (semi-)continuous data points along the ice core.
Paul D. Bons, Tamara de Riese, Steven Franke, Maria-Gema Llorens, Till Sachau, Nicolas Stoll, Ilka Weikusat, Julien Westhoff, and Yu Zhang
The Cryosphere, 15, 2251–2254, https://doi.org/10.5194/tc-15-2251-2021, https://doi.org/10.5194/tc-15-2251-2021, 2021
Short summary
Short summary
The modelling of Smith-Johnson et al. (The Cryosphere, 14, 841–854, 2020) suggests that a very large heat flux of more than 10 times the usual geothermal heat flux is required to have initiated or to control the huge Northeast Greenland Ice Stream. Our comparison with known hotspots, such as Iceland and Yellowstone, shows that such an exceptional heat flux would be unique in the world and is incompatible with known geological processes that can raise the heat flux.
Sebastian Hellmann, Johanna Kerch, Ilka Weikusat, Andreas Bauder, Melchior Grab, Guillaume Jouvet, Margit Schwikowski, and Hansruedi Maurer
The Cryosphere, 15, 677–694, https://doi.org/10.5194/tc-15-677-2021, https://doi.org/10.5194/tc-15-677-2021, 2021
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We analyse the orientation of ice crystals in an Alpine glacier and compare this orientation with the ice flow direction. We found that the crystals orient in the direction of the largest stress which is in the flow direction in the upper parts of the glacier and in the vertical direction for deeper zones of the glacier. The grains cluster around this maximum stress direction, in particular four-point maxima, most likely as a result of recrystallisation under relatively warm conditions.
Helle Astrid Kjær, Patrick Zens, Ross Edwards, Martin Olesen, Ruth Mottram, Gabriel Lewis, Christian Terkelsen Holme, Samuel Black, Kasper Holst Lund, Mikkel Schmidt, Dorthe Dahl-Jensen, Bo Vinther, Anders Svensson, Nanna Karlsson, Jason E. Box, Sepp Kipfstuhl, and Paul Vallelonga
The Cryosphere Discuss., https://doi.org/10.5194/tc-2020-337, https://doi.org/10.5194/tc-2020-337, 2021
Manuscript not accepted for further review
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We have reconstructed accumulation in 6 firn cores and 8 snow cores in Northern Greenland and compared with a regional Climate model over Greenland. We find the model underestimate precipitation especially in north-eastern part of the ice cap- an important finding if aiming to reconstruct surface mass balance.
Temperatures at 10 meters depth at 6 sites in Greenland were also determined and show a significant warming since the 1990's of 0.9 to 2.5 °C.
Seyedhamidreza Mojtabavi, Frank Wilhelms, Eliza Cook, Siwan M. Davies, Giulia Sinnl, Mathias Skov Jensen, Dorthe Dahl-Jensen, Anders Svensson, Bo M. Vinther, Sepp Kipfstuhl, Gwydion Jones, Nanna B. Karlsson, Sergio Henrique Faria, Vasileios Gkinis, Helle Astrid Kjær, Tobias Erhardt, Sarah M. P. Berben, Kerim H. Nisancioglu, Iben Koldtoft, and Sune Olander Rasmussen
Clim. Past, 16, 2359–2380, https://doi.org/10.5194/cp-16-2359-2020, https://doi.org/10.5194/cp-16-2359-2020, 2020
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We present a first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination. After field measurements and processing of the ice-core data, the GICC05 timescale is transferred from the NGRIP core to the EGRIP core by means of matching volcanic events and common patterns (381 match points) in the ECM and DEP records. The new timescale is named GICC05-EGRIP-1 and extends back to around 15 kyr b2k.
Alexander H. Weinhart, Johannes Freitag, Maria Hörhold, Sepp Kipfstuhl, and Olaf Eisen
The Cryosphere, 14, 3663–3685, https://doi.org/10.5194/tc-14-3663-2020, https://doi.org/10.5194/tc-14-3663-2020, 2020
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From 1 m snow profiles along a traverse on the East Antarctic Plateau, we calculated a representative surface snow density of 355 kg m−3 for this region with an error less than 1.5 %.
This density is 10 % higher and density fluctuations seem to happen on smaller scales than climate model outputs suggest. Our study can help improve the parameterization of surface snow density in climate models to reduce the error in future sea level predictions.
Jean-Louis Bonne, Hanno Meyer, Melanie Behrens, Julia Boike, Sepp Kipfstuhl, Benjamin Rabe, Toni Schmidt, Lutz Schönicke, Hans Christian Steen-Larsen, and Martin Werner
Atmos. Chem. Phys., 20, 10493–10511, https://doi.org/10.5194/acp-20-10493-2020, https://doi.org/10.5194/acp-20-10493-2020, 2020
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This study introduces 2 years of continuous near-surface in situ observations of the stable isotopic composition of water vapour in parallel with precipitation in north-eastern Siberia. We evaluate the atmospheric transport of moisture towards the region of our observations with simulations constrained by meteorological reanalyses and use this information to interpret the temporal variations of the vapour isotopic composition from seasonal to synoptic timescales.
Anders Svensson, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Thomas Blunier, Sune O. Rasmussen, Bo M. Vinther, Paul Vallelonga, Emilie Capron, Vasileios Gkinis, Eliza Cook, Helle Astrid Kjær, Raimund Muscheler, Sepp Kipfstuhl, Frank Wilhelms, Thomas F. Stocker, Hubertus Fischer, Florian Adolphi, Tobias Erhardt, Michael Sigl, Amaelle Landais, Frédéric Parrenin, Christo Buizert, Joseph R. McConnell, Mirko Severi, Robert Mulvaney, and Matthias Bigler
Clim. Past, 16, 1565–1580, https://doi.org/10.5194/cp-16-1565-2020, https://doi.org/10.5194/cp-16-1565-2020, 2020
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We identify signatures of large bipolar volcanic eruptions in Greenland and Antarctic ice cores during the last glacial period, which allows for a precise temporal alignment of the ice cores. Thereby the exact timing of unexplained, abrupt climatic changes occurring during the last glacial period can be determined in a global context. The study thus provides a step towards a full understanding of elements of the climate system that may also play an important role in the future.
Ernst-Jan N. Kuiper, Ilka Weikusat, Johannes H. P. de Bresser, Daniela Jansen, Gill M. Pennock, and Martyn R. Drury
The Cryosphere, 14, 2429–2448, https://doi.org/10.5194/tc-14-2429-2020, https://doi.org/10.5194/tc-14-2429-2020, 2020
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A composite flow law model applied to crystal size distributions from the NEEM deep ice core predicts that fine-grained layers in ice from the last Glacial period localize deformation as internal shear zones in the Greenland ice sheet deforming by grain-size-sensitive creep. This prediction is consistent with microstructures in Glacial age ice.
Ernst-Jan N. Kuiper, Johannes H. P. de Bresser, Martyn R. Drury, Jan Eichler, Gill M. Pennock, and Ilka Weikusat
The Cryosphere, 14, 2449–2467, https://doi.org/10.5194/tc-14-2449-2020, https://doi.org/10.5194/tc-14-2449-2020, 2020
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Fast ice flow occurs in deeper parts of polar ice sheets, driven by high stress and high temperatures. Above 262 K ice flow is further enhanced, probably by the formation of thin melt layers between ice crystals. A model applying an experimentally derived composite flow law, using temperature and grain size values from the deepest 540 m of the NEEM ice core, predicts that flow in fine-grained layers is enhanced by a factor of 10 compared to coarse-grained layers in the Greenland ice sheet.
Tetsuro Taranczewski, Johannes Freitag, Olaf Eisen, Bo Vinther, Sonja Wahl, and Sepp Kipfstuhl
The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-280, https://doi.org/10.5194/tc-2018-280, 2019
Preprint withdrawn
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We used melt layers detected in ice cores from the Renland ice cap in East Greenland to find evidence of past climate trends in this region. Our record provides such information for the past 10,000 years. We developed an attempt to increase the reliability of such a record by correcting deformation-induced biases. It proves that such simple to obtain melt records can be used to gather information about paleoclimate especially for regions where climate records are sparse.
Jilu Li, Jose A. Vélez González, Carl Leuschen, Ayyangar Harish, Prasad Gogineni, Maurine Montagnat, Ilka Weikusat, Fernando Rodriguez-Morales, and John Paden
The Cryosphere, 12, 2689–2705, https://doi.org/10.5194/tc-12-2689-2018, https://doi.org/10.5194/tc-12-2689-2018, 2018
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Ice properties inferred from multi-polarization measurements can provide insight into ice strain, viscosity, and ice flow. The Center for Remote Sensing of Ice Sheets used a ground-based radar for multi-channel and multi-polarization measurements at the NEEM site. This paper describes the radar system, antenna configurations, data collection, and processing and analysis of this data set. Comparisons between the radar observations, simulations, and ice core fabric data are in very good agreement.
Johanna Kerch, Anja Diez, Ilka Weikusat, and Olaf Eisen
The Cryosphere, 12, 1715–1734, https://doi.org/10.5194/tc-12-1715-2018, https://doi.org/10.5194/tc-12-1715-2018, 2018
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We investigate the effect of crystal anisotropy on seismic velocities in glacier ice by calculating seismic phase velocities using the exact c axis angles to describe the crystal orientations in ice-core samples for an alpine and a polar ice core. Our results provide uncertainty estimates for earlier established approximative calculations. Additionally, our findings highlight the variation in seismic velocity at non-vertical incidence as a function of the horizontal azimuth of the seismic plane.
Nancy A. N. Bertler, Howard Conway, Dorthe Dahl-Jensen, Daniel B. Emanuelsson, Mai Winstrup, Paul T. Vallelonga, James E. Lee, Ed J. Brook, Jeffrey P. Severinghaus, Taylor J. Fudge, Elizabeth D. Keller, W. Troy Baisden, Richard C. A. Hindmarsh, Peter D. Neff, Thomas Blunier, Ross Edwards, Paul A. Mayewski, Sepp Kipfstuhl, Christo Buizert, Silvia Canessa, Ruzica Dadic, Helle A. Kjær, Andrei Kurbatov, Dongqi Zhang, Edwin D. Waddington, Giovanni Baccolo, Thomas Beers, Hannah J. Brightley, Lionel Carter, David Clemens-Sewall, Viorela G. Ciobanu, Barbara Delmonte, Lukas Eling, Aja Ellis, Shruthi Ganesh, Nicholas R. Golledge, Skylar Haines, Michael Handley, Robert L. Hawley, Chad M. Hogan, Katelyn M. Johnson, Elena Korotkikh, Daniel P. Lowry, Darcy Mandeno, Robert M. McKay, James A. Menking, Timothy R. Naish, Caroline Noerling, Agathe Ollive, Anaïs Orsi, Bernadette C. Proemse, Alexander R. Pyne, Rebecca L. Pyne, James Renwick, Reed P. Scherer, Stefanie Semper, Marius Simonsen, Sharon B. Sneed, Eric J. Steig, Andrea Tuohy, Abhijith Ulayottil Venugopal, Fernando Valero-Delgado, Janani Venkatesh, Feitang Wang, Shimeng Wang, Dominic A. Winski, V. Holly L. Winton, Arran Whiteford, Cunde Xiao, Jiao Yang, and Xin Zhang
Clim. Past, 14, 193–214, https://doi.org/10.5194/cp-14-193-2018, https://doi.org/10.5194/cp-14-193-2018, 2018
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Temperature and snow accumulation records from the annually dated Roosevelt Island Climate Evolution (RICE) ice core show that for the past 2 700 years, the eastern Ross Sea warmed, while the western Ross Sea showed no trend and West Antarctica cooled. From the 17th century onwards, this dipole relationship changed. Now all three regions show concurrent warming, with snow accumulation declining in West Antarctica and the eastern Ross Sea.
Thomas Laepple, Thomas Münch, Mathieu Casado, Maria Hoerhold, Amaelle Landais, and Sepp Kipfstuhl
The Cryosphere, 12, 169–187, https://doi.org/10.5194/tc-12-169-2018, https://doi.org/10.5194/tc-12-169-2018, 2018
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We explain why snow pits across different sites in East Antarctica show visually similar isotopic variations. We argue that the similarity and the apparent cycles of around 20 cm in the δD and δ18O variations are the result of a seasonal cycle in isotopes, noise, for example from precipitation intermittency, and diffusion. The near constancy of the diffusion length across many ice-coring sites explains why the structure and cycle length is largely independent of the accumulation conditions.
Thomas van der Werf, Vasileios Chatzaras, Leo Marcel Kriegsman, Andreas Kronenberg, Basil Tikoff, and Martyn R. Drury
Solid Earth, 8, 1211–1239, https://doi.org/10.5194/se-8-1211-2017, https://doi.org/10.5194/se-8-1211-2017, 2017
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The strength of Earth's lower crust affects the cycle of earthquakes in tectonic plate boundaries. To understand the mechanical properties of the lower crust beneath northern Baja California, Mexico, we studied rocks, which were transferred to the surface during the eruption of Quaternary volcanoes. The lower crust is strongly deformed, hot, and dry. During transient events of deformation, the lower crust is weak, and its strength is similar to the strength of the upper mantle.
Tim Carlsen, Gerit Birnbaum, André Ehrlich, Johannes Freitag, Georg Heygster, Larysa Istomina, Sepp Kipfstuhl, Anaïs Orsi, Michael Schäfer, and Manfred Wendisch
The Cryosphere, 11, 2727–2741, https://doi.org/10.5194/tc-11-2727-2017, https://doi.org/10.5194/tc-11-2727-2017, 2017
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The optical size of snow grains (ropt) affects the reflectivity of snow surfaces and thus the local surface energy budget in particular in polar regions. The temporal evolution of ropt retrieved from ground-based, airborne, and spaceborne remote sensing could reproduce optical in situ measurements for a 2-month period in central Antarctica (2013/14). The presented validation study provided a unique testbed for retrievals of ropt under Antarctic conditions where in situ data are scarce.
Thomas Münch, Sepp Kipfstuhl, Johannes Freitag, Hanno Meyer, and Thomas Laepple
The Cryosphere, 11, 2175–2188, https://doi.org/10.5194/tc-11-2175-2017, https://doi.org/10.5194/tc-11-2175-2017, 2017
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The importance of post-depositional changes for the temperature interpretation of water isotopes is poorly constrained by observations. Here, for the first time, temporal isotope changes in the open-porous firn are directly analysed using a large array of shallow isotope profiles. By this, we can reject the possibility of post-depositional change beyond diffusion and densification as the cause of the discrepancy between isotope and local temperature variations at Kohnen Station, East Antarctica.
Jan Eichler, Ina Kleitz, Maddalena Bayer-Giraldi, Daniela Jansen, Sepp Kipfstuhl, Wataru Shigeyama, Christian Weikusat, and Ilka Weikusat
The Cryosphere, 11, 1075–1090, https://doi.org/10.5194/tc-11-1075-2017, https://doi.org/10.5194/tc-11-1075-2017, 2017
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This study contributes to investigations of the effect of impurities on ice microstructure and flow properties. For the first time we mapped over 5000 micro-inclusions in four samples from the EDML and NEEM polar ice cores. The particle distributions show no correlation with grain boundaries and thus we conclude that particle pinning plays only a secondary role for the microstructure evolution. Alternative mechanisms are discussed.
Florian Steinbach, Paul D. Bons, Albert Griera, Daniela Jansen, Maria-Gema Llorens, Jens Roessiger, and Ilka Weikusat
The Cryosphere, 10, 3071–3089, https://doi.org/10.5194/tc-10-3071-2016, https://doi.org/10.5194/tc-10-3071-2016, 2016
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How glaciers or ice sheets flow is a result of microscopic processes controlled by the properties of individual ice crystals. We performed computer simulations on these processes and the effect of air bubbles between crystals. The simulations show that small-scale ice deformation is locally stronger than in other regions, which is enhanced by bubbles. This causes the ice crystals to recrystallise and change their properties in a way that potentially also affects the large-scale flow properties.
Christoph Florian Schaller, Johannes Freitag, Sepp Kipfstuhl, Thomas Laepple, Hans Christian Steen-Larsen, and Olaf Eisen
The Cryosphere, 10, 1991–2002, https://doi.org/10.5194/tc-10-1991-2016, https://doi.org/10.5194/tc-10-1991-2016, 2016
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Along a traverse through North Greenland in May 2015 we collected snow cores up to 2 m in depth and analyzed their properties (e.g., density). A new technique for this sampling and an adapted algorithm for comparing data sets from different positions and aligning stratigraphic features are presented. We find good agreement of the density layering in the snowpack over hundreds of kilometers. This allows the construction of a representative density profile that is statistically validated.
François Ritter, Hans Christian Steen-Larsen, Martin Werner, Valérie Masson-Delmotte, Anais Orsi, Melanie Behrens, Gerit Birnbaum, Johannes Freitag, Camille Risi, and Sepp Kipfstuhl
The Cryosphere, 10, 1647–1663, https://doi.org/10.5194/tc-10-1647-2016, https://doi.org/10.5194/tc-10-1647-2016, 2016
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We present successful continuous measurements of water vapor isotopes performed in Antarctica in January 2013. The interest is to understand the impact of the water vapor isotopic composition on the near-surface snow isotopes. Our study reveals a diurnal cycle in the snow isotopic composition in phase with the vapor. This finding suggests fractionation during the sublimation of the ice, which has an important consequence on the interpretation of water isotope variations in ice cores.
Thomas Münch, Sepp Kipfstuhl, Johannes Freitag, Hanno Meyer, and Thomas Laepple
Clim. Past, 12, 1565–1581, https://doi.org/10.5194/cp-12-1565-2016, https://doi.org/10.5194/cp-12-1565-2016, 2016
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Ice-core oxygen isotope ratios are a key climate archive to infer past temperatures, an interpretation however complicated by non-climatic noise. Based on 50 m firn trenches, we present for the first time a two-dimensional view (vertical × horizontal) of how oxygen isotopes are stored in Antarctic firn. A statistical noise model allows inferences for the validity of ice coring efforts to reconstruct past temperatures, highlighting the need of replicate cores for Holocene climate reconstructions.
D. Jansen, M.-G. Llorens, J. Westhoff, F. Steinbach, S. Kipfstuhl, P. D. Bons, A. Griera, and I. Weikusat
The Cryosphere, 10, 359–370, https://doi.org/10.5194/tc-10-359-2016, https://doi.org/10.5194/tc-10-359-2016, 2016
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In this study we present examples of typical small-scale folds observed in the NEEM ice core, North Greenland, and discuss their characteristics. Numerical modelling of viscoplastic deformation and dynamic recrystallisation was used to improve the understanding of the formation of the observed structures under simple shear boundary conditions. We conclude that the folds originate from bands of grains with a tilted lattice relative to the strong lattice preferred orientation below 1500 m depth.
S. Weißbach, A. Wegner, T. Opel, H. Oerter, B. M. Vinther, and S. Kipfstuhl
Clim. Past, 12, 171–188, https://doi.org/10.5194/cp-12-171-2016, https://doi.org/10.5194/cp-12-171-2016, 2016
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Based on a set of 12 intermediate deep ice cores, covering an area of about 200 000 km2, we studied the spatial and temporal d18O patterns of northern Greenland over the past millennium and found a strong east-west gradient related to the main ice divide. A stacked record with significantly reduced noise revealed distinct climate variations with a pronounced Little Ice Age and distinct warm events such as the Medieval Climate Anomaly, around AD 1420 and in the 20th century.
A. Svensson, S. Fujita, M. Bigler, M. Braun, R. Dallmayr, V. Gkinis, K. Goto-Azuma, M. Hirabayashi, K. Kawamura, S. Kipfstuhl, H. A. Kjær, T. Popp, M. Simonsen, J. P. Steffensen, P. Vallelonga, and B. M. Vinther
Clim. Past, 11, 1127–1137, https://doi.org/10.5194/cp-11-1127-2015, https://doi.org/10.5194/cp-11-1127-2015, 2015
J. Christmann, R. Müller, K. G. Webber, D. Isaia, F. H. Schader, S. Kipfstuhl, J. Freitag, and A. Humbert
Earth Syst. Sci. Data, 7, 87–92, https://doi.org/10.5194/essd-7-87-2015, https://doi.org/10.5194/essd-7-87-2015, 2015
A. Diez, O. Eisen, C. Hofstede, A. Lambrecht, C. Mayer, H. Miller, D. Steinhage, T. Binder, and I. Weikusat
The Cryosphere, 9, 385–398, https://doi.org/10.5194/tc-9-385-2015, https://doi.org/10.5194/tc-9-385-2015, 2015
C. Elsässer, D. Wagenbach, I. Levin, A. Stanzick, M. Christl, A. Wallner, S. Kipfstuhl, I. K. Seierstad, H. Wershofen, and J. Dibb
Clim. Past, 11, 115–133, https://doi.org/10.5194/cp-11-115-2015, https://doi.org/10.5194/cp-11-115-2015, 2015
P. Vallelonga, K. Christianson, R. B. Alley, S. Anandakrishnan, J. E. M. Christian, D. Dahl-Jensen, V. Gkinis, C. Holme, R. W. Jacobel, N. B. Karlsson, B. A. Keisling, S. Kipfstuhl, H. A. Kjær, M. E. L. Kristensen, A. Muto, L. E. Peters, T. Popp, K. L. Riverman, A. M. Svensson, C. Tibuleac, B. M. Vinther, Y. Weng, and M. Winstrup
The Cryosphere, 8, 1275–1287, https://doi.org/10.5194/tc-8-1275-2014, https://doi.org/10.5194/tc-8-1275-2014, 2014
M. Montagnat, N. Azuma, D. Dahl-Jensen, J. Eichler, S. Fujita, F. Gillet-Chaulet, S. Kipfstuhl, D. Samyn, A. Svensson, and I. Weikusat
The Cryosphere, 8, 1129–1138, https://doi.org/10.5194/tc-8-1129-2014, https://doi.org/10.5194/tc-8-1129-2014, 2014
H. C. Steen-Larsen, V. Masson-Delmotte, M. Hirabayashi, R. Winkler, K. Satow, F. Prié, N. Bayou, E. Brun, K. M. Cuffey, D. Dahl-Jensen, M. Dumont, M. Guillevic, S. Kipfstuhl, A. Landais, T. Popp, C. Risi, K. Steffen, B. Stenni, and A. E. Sveinbjörnsdottír
Clim. Past, 10, 377–392, https://doi.org/10.5194/cp-10-377-2014, https://doi.org/10.5194/cp-10-377-2014, 2014
S. O. Rasmussen, P. M. Abbott, T. Blunier, A. J. Bourne, E. Brook, S. L. Buchardt, C. Buizert, J. Chappellaz, H. B. Clausen, E. Cook, D. Dahl-Jensen, S. M. Davies, M. Guillevic, S. Kipfstuhl, T. Laepple, I. K. Seierstad, J. P. Severinghaus, J. P. Steffensen, C. Stowasser, A. Svensson, P. Vallelonga, B. M. Vinther, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 2713–2730, https://doi.org/10.5194/cp-9-2713-2013, https://doi.org/10.5194/cp-9-2713-2013, 2013
A. Svensson, M. Bigler, T. Blunier, H. B. Clausen, D. Dahl-Jensen, H. Fischer, S. Fujita, K. Goto-Azuma, S. J. Johnsen, K. Kawamura, S. Kipfstuhl, M. Kohno, F. Parrenin, T. Popp, S. O. Rasmussen, J. Schwander, I. Seierstad, M. Severi, J. P. Steffensen, R. Udisti, R. Uemura, P. Vallelonga, B. M. Vinther, A. Wegner, F. Wilhelms, and M. Winstrup
Clim. Past, 9, 749–766, https://doi.org/10.5194/cp-9-749-2013, https://doi.org/10.5194/cp-9-749-2013, 2013
Related subject area
Glaciology
Strain field evolution at the ductile-to-brittle transition: a case study on ice
Thomas Chauve, Maurine Montagnat, Cedric Lachaud, David Georges, and Pierre Vacher
Solid Earth, 8, 943–953, https://doi.org/10.5194/se-8-943-2017, https://doi.org/10.5194/se-8-943-2017, 2017
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For the first time, digital image correlation was used to follow strain field development and evolution during micro-cracking, at the ductile-to-brittle transition in polycrystalline ice.
Owing to the high-temperature conditions of the tests, dynamic recrystallization mechanisms (nucleation and sub-grain rotation) efficiently participate in the stress redistribution during and after crack opening, and even lead to local crack closure.
Cited articles
Alley, R., Gow, A., and Meese, D.: Mapping c-axis fabrics to study physical processes in ice, J. Glaciol., 41, 197–203, 1995.
Alley, R. B.: Flow-law hypotheses for ice-sheet modelling, J. Glaciol., 38, 245–256, 1992.
Alley, R. B., Clark, P. U., Huybrechts, P., and Joughin, I.: Ice-Sheet and Sea-Level Changes, Science, 310, 456–460, 2005.
Arnaud, L., M., G., Barnola, J. M., and Duval, P.: Imaging firn and bubly ice in coaxial reflected light: a new technique for the characterization of these porous media, J. Glaciol., 44, 326–332, 1998.
Ashby, M. F.: The deformation of plastically non-homogenous materials, Philos. Mag., 21, 399–424, 1970.
Ashby, M. F. and Duval, P.: The creep of polycrystalline ice, Cold Reg. Sci. Technol., 11, 285–300, 1985.
Baker, I.: Imaging dislocations in ice, Microsc. Res. Techn., 62, 70–82, 2003.
Barnes, P. R. F.: Comment on “Grain boundary ridge on sintered bonds between ice crystals” [J. Appl. Phys. 90, 5782 (2001)], J. Appl. Phys., 93, 783–785, 2003.
Barrette, P. D. and Sinha, N. K.: Lattice misfit as revealed by dislocation etch pits in a deformed ice crystal, J. Mater. Sci. Lett., 13, 1478–1481, 1994.
Beem, L. H., Jezek, K. C., and Van Der Veen, C.: Basal melt rates beneath Whillans ice stream, west antarctica, J. Glaciol., 56, 647–654, 2010.
Binder, T., Garbe, C., Wagenbach, D., Freitag, J., and Kipfstuhl, S.: Extraction and parameterization of grain boundary networks, using a dedicated method of automatic image analysis, J. Microsc., 250, 130–141, 2013a.
Binder, T., Weikusat, I., Freitag, F., Garbe, C., Wagenbach, D., and Kipfstuhl, S.: Microstructure through an ice sheet, Materials Science Forum 753, 481–484, Trans Tech Publications, Switzerland, Proceedings of ReX&GG2013, 5–10 May 2013, Sydney, 2013b.
Bindoff, N. L., Willebrand, J., Artale, V., Cazenave, A., Gregory, J., Gulev, S., Hanawa, K., Quere, C. K., Levitus, S., Nojiri, Y., Shum, C., Talley, L., and Unnikrishnan, A.: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, chap. Observations, Oceanic Climate Change and Sea Level, 385–432, 2007.
Bons, P. D., Jansen, D., Mundel, F., Bauer, C. C., Binder, T., Eisen, O., Jessell, M. W., Llorens, M.-G., Steinbach, F., Steinhage, D., and Weikusat, I.: Converging flow and anisotropy cause largescale folding in Greenland's ice sheet, Nat. Commun., 7, 11427, https://doi.org/10.1038/ncomms11427, 2016.
Breton, D. J., Baker, I., and Cole, D. M.: Microstructural evolution of polycrystalline ice during confined creep testing, Cold Reg. Sci. Technol., 127, 25–36, 2016.
Bryant, G. W. and Mason, B. J.: Etch pits and dislocations in ice crystals, Phil. Mag., Structure and Properties of Condensed Matter, 5, 1221–1227, 1960.
Chauve, T., Montagnat, M., Piazolo, S. C., Journaux, B., Wheeler, J., Barou, F., Mainprice, D., and Tommasi, A.: Non-basal dislocations should be accounted for in simulating ice mass flow, Earth Planet. Sc. Lett., 473, 247–255, https://doi.org/10.1016/j.epsl.2017.06.020, 2017.
Dansgaard, W., Clausen, H. B., Gundestrup, N., Hammer, C. U., Johnsen, S. F., Kristinsdottir, P. M., and Reeh, N.: A New Greenland Deep Ice Core, Science, 218, 1273–1277, 1982.
Drury, M. and Pennock, G.: Subgrain Rotation Recrystallization in Minerals Materials, Sci. Forum, 550, 95–104, 2007.
Drury, M., Humphreys, F., and White, S.: Large strain deformation studies using polycrystalline magnesium as a rock analogue. Part II: dynamic recrystallisation mechanisms at high temperatures, Phys. Earth Planet. In., 40, 201–207, 1985.
Duval, P. and Montagnat, M.: Comment on “Superplastic deformation of ice: Experimental observations” by D. L. Goldsby and D. L. Kohlstedt, J. Geophys. Res.-Sol. Ea., 107, 2082, https://doi.org/10.1029/2001JB000946, 2002.
Duval, P., Ashby, M. F., and Anderman, I.: Rate-contolling processes in the creep of polycrystalline ice, J. Phys. Chem., 87, 4066–4074, 1983.
Eichler, J., Weikusat, I., and Kipfstuhl, S.: Orientation-tensor eigenvalues along the NEEM ice core, https://doi.org/10.1594/PANGAEA.838059, 2013.
Eichler, J., Kleitz, I., Bayer-Giraldi, M., Jansen, D., Kipfstuhl, S., Shigeyama, W., Weikusat, C., and Weikusat, I.: Location and distribution of micro-inclusions in the EDML and NEEM ice cores using optical microscopy and in situ Raman spectroscopy, The Cryosphere, 11, 1075–1090, https://doi.org/10.5194/tc-11-1075-2017, 2017.
EPICA: Eight glacial cycles from an Antarctic ice core, Nature, 429, 623–628, 2004.
EPICA: One-to-one coupling of glacial climate variability in Greenland and Antarctica, Nature, 444, 195–198, 2006.
Faria, S. H., Weikusat, I., and Azuma, N.: The Microstructure of Polar Ice. Part I: Highlights from ice core research, J. Struct. Geol., 61, 2–20, 2014a.
Faria, S. H., Weikusat, I., and Azuma, N.: The microstructure of polar ice. part II: State of the art, Journal of Structural Geology, 61, 21–49, 2014b.
Fitzpatrick, J. J., Voight, D. E., Fegyveresi, J. M., Stevens, N. T., Spencer, M. K., Cole-Dai, J., Alley, R. B., Jardine, G. E., Cravens, E. D., Wilen, L. A., Fudge, T., and McConnell, J. R.: Physical properties of the WAIS Divide ice core, J. Glaciol., 60, 1181–1198, 2014.
Fukuda, A. and Higashi, A.: X-ray diffraction topographic studies of dislocations in natural large ice single crystals, Jpn. J. Appl. Phys., 8, 993–999, 1969.
Fukuda, A., Hondoh, T., and Higashi, A.: Dislocation mechansisms of plastic deformation of ice, J. Phys., 48, 163–171, 1987.
Gifkins, R. C.: Grain-boundary sliding and its accommodation during creep and superplasticity, Metall. Trans. A, 7, 1225–1232, 1976.
Glen, J. W.: The creep of polycrystalline ice, P. R. Soc. Lond. A, 228, 519–538, 1955.
Goldsby, D. and Kohlstedt, D.: Grain boundary sliding in fine-grained ice, Scripta Mater., 37, 1399–1406, 1997.
Goldsby, D. L. and Kohlstedt, D. L.: Superplastic deformation of ice: experimental observations, J. Geophys. Res.-Sol. Ea., 106, 11017–11030, 2001.
Goldsby, D. L. and Kohlstedt, D. L.: Superplastic deformation of ice: experimental observations: reply, J. Geophys. Res.-Sol. Ea., 107, 2313, https://doi.org/10.1029/2002JB001842, 2002.
Gottstein, G. and Shvindlerman, L. S.: Grain boundary migration in metals, CRC Press, Taylor & Francis Group, Boca Raton, London, New York, 1999.
Greve, R. and Blatter, H.: Dynamics of Ice Sheets and Glaciers, edited by: Hutter, K., Springer-Verlag Berlin Heidelberg, 287 pp., 2009.
Hamann, I., Weikusat, C., Azuma, N., and Kipfstuhl, S.: Evolution of ice crystal microstructures during creep experiments, J. Glaciol., 53, 479–489, 2007.
Higashi, A., Fukuda, A., Shoji, H., Oguro, M., Hondoh, T., and Goto-Azuma, K.: Lattice defects in ice crystals, Hokkaido University Press, Sapporo, Japan, 1988.
Hirth, J. P. and Lothe, J.: Theory of Dislocations. Krieger Publishing Company, 857 pp., 1982.
Hock, R.: Glacier melt: a review of processes and their modelling, Prog. Phys. Geogr., 29, 362–391, 2005.
Hondoh, T.: Nature and behaviour of dislocations in ice, in: Physics of Ice Core Records, edited by: Hondoh, T., Hokkaido University Press, Sapporo, 3–24, 2000.
Hondoh, T.: Anisotropy of ice plasticity and dislocations in ice : anomalous properties of hexagonal ice Ih associated with cubic structure Ic Low temperature, Science, 64, 141–156, 2006.
Hondoh, T.: An overview of microphysical processes in ice sheets: Toward nanoglaciology, in: Physics of Ice Core Records II, edited by: Hondoh, T., Vol. 68, Supplement Issue of Low Temperature Science, 2010.
Hughes, T.: Modeling ice sheets from the bottom up, Quaternary Sci. Rev., 28, 1831–1849, 2009.
Humphreys, F.: Characterisation of fine-scale microstructures by electron backscatter diffraction (EBSD), Scr. Mater., 51, 771–776, 2004.
Humphreys, F. J. and Hatherly, M.: Recrystallization and Related Annealing Phenomena, Elsevier, Oxford, UK, 574 pp., 2004.
Hutchinson, J. W.: Creep and plasticity of hexagonal polycrystals as related to single crystal slip, Metall. Mater. Trans. A, 8, 1465–1469, 1977.
Huybrechts, P.: Ice Sheet Modeling, chap. Encyclopedia of the Antarctic, Routledge, New York and London, 514–517, 2007.
Iliescu, D., Baker, I., and Chang, H.: Determining the Orientations of Ice Crystals Using Electron Backscatter Patterns, Microsc. Res. Techniq., 63, 183–187, 2004.
Ion, S., Humphreys, F., and White, S. H.: Dynamic recrystallisation and the development of microstructure during the high temperature deformation of magnesium, Acta Metall., 30, 1909–1919, 1982.
IPCC: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, chap. Summary for Policymakers, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK and New York, NY, USA, 2007.
IPCC: Climate change 2014: Synthesis report. contribution of working groups I, II and III to the Fifth assessment report of the intergovernmental panel on climate change, Core Writing Team, edited by: Pachauri, R. K. and Meyer, L. A., IPCC, Geneva, Switzerland, 151, 2014.
Jansen, D., Llorens, M.-G., Westhoff, J., Steinbach, F., Kipfstuhl, S., Bons, P. D., Griera, A., and Weikusat, I.: Small-scale disturbances in the stratigraphy of the NEEM ice core: observations and numerical model simulations, The Cryosphere, 10, 359–370, https://doi.org/10.5194/tc-10-359-2016, 2016.
Joughin, I., Smith, B., Howat, I., and Scambos, T.: MEaSUREs Greenland Ice Velocity Map from InSAR Data, Version 2. Boulder, Colorado, USA: NASA DAAC at the National Snow and Ice Data Center, https://doi.org/10.5067/OC7B04ZM9G6Q, 2015.
Ketcham, W. M. and Hobbs, P. V.: An experimental determination of the surface energies of ice, Philos. Mag., 19, 1161–1173, 1969.
Kipfstuhl, S., Hamann, I., Lambrecht, A., Freitag, J., Faria, S., Grigoriev, D., and Azuma, N.: Microstructure mapping: a new method for imaging deformation induced microstructural features of ice on the grain scale, J. Glaciol., 52, 398–406, 2006.
Kipfstuhl, S., Faria, S. H., Azuma, N., Freitag, J., Hamann, I., Kaufmann, P., Miller, H., Weiler, K., and Wilhelms, F.: Evidence of dynamic recrystallization in polar firn, J. Geophys. Res., 114, B05204, https://doi.org/10.1029/2008JB005583, 2009.
Krischke, A., Oechsner, U., and Kipfstuhl, S.: Microstructure Analysis of Polar Ice Cores Physics' Best, DPG, WILEY-VCH Verlag, Weinheim, 20–22, 2015a.
Krischke, A., Oechsner, U., and Kipfstuhl, S.: Rapid Microstructure Analysis of Polar Ice Cores Optik & Photonik, WILEY-VCH Verlag, Weinheim, 10, 32–35, 2015b.
Kuramoto, T., Goto-Azuma, K., Hirabayashi, M., Miyake, T., Motoyama, H., Dahl-Jensen, D., and Steffensen, J. P.: Seasonal variations of snow chemistry at NEEM, Greenland, Ann. Glaciol., 52, 193–200, 2011.
Lemke, P., Ren, J., Alley, R., Allison, I., Carrasco, J., Flato, G., Fujii, Y., Kaser, G., Mote, P., Thomas, R., and Zhang, T.: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK and New York, NY, USA, 337–383, 2007.
Levi, L., DeAchaval, E. M., and Suraski, E.: Experimental study of non-basal dislocations in ice crystals, J. Glaciol., 5, 691–699, 1965.
Lloyd, G. E., Farmer, A. B., and Mainprice, D.: Misorientation analysis and the formation and orientation of subgrain and grain boundaries, Tectonophysics, 279, 55–78, 1997.
Llorens, M.-G., Griera, A., Bons, P. D., Lebensohn, R. A., Evans, L. A., Jansen, D., and Weikusat, I.: Full-field predictions of ice dynamic recrystallisation under simple shear conditions, Earth Planet. Sc. Lett., 450, 233–242, 2016.
Llorens, M.-G., Griera, A., Steinbach, F., Bons, P. D., Gomez-Rivas, E., Jansen, D., Roessiger, J., Lebensohn, R. A., and Weikusat, I.: Dynamic recrystallisation during deformation of polycrystalline ice: insights from numerical simulations, Philos. T. R. Soc. A, 375, 20150346, https://doi.org/10.1098/rsta.2015.0346, 2017.
Llorens Verde, M. G., Griera, A., Bons, P. D., Roessiger, J., Lebensohn, R., Evans, L., and Weikusat, I.: Dynamic recrystallisation of ice aggregates during co-axial viscoplastic deformation: a numerical approach, J. Glaciol., 62, 359–377, 2016.
Mainprice, D., Lloyd, G. E., and Casey, M.: Individual orientation measurements in quartz polycrystals – advantages and limitations for texture and petrophysical property determinations, J. Struct. Geol., 15, 1169–1187, 1993.
Means, W. D. and Ree, J. H.: Seven types of subgrain boundaries in OCP, J. Struct. Geol., 10, 765–770, 1988.
Miyamoto, A., Saito, T., and Hondoh, T.: Visual observation of volume relaxation under different storage temperatures in the dome fuji ice core, Antarctica, in: Physics of Ice Core Records II, edited by: Hondoh, T., Vol. 2 of PICR, 68, 73–79, 2009.
Miyamoto, A., Weikusat, I., and Hondoh, T.: Complete determination of ice crystal orientation and microstructure investigation on ice core samples enabled by a new x-ray laue diffraction method, J. Glaciol., 57, 67–74, 2011.
Montagnat, M. and Duval, P.: Rate controlling processes in the creep of polar ice, influence of grain boundary migration associated with recrystallization, Earth Planet. Sc. Lett., 183, 179–186, 2000.
Montagnat, M. and Duval, P.: Dislocations in ice and deformation mechanisms: from single crystals to polar ice, Defect and Diffusion Forum, Scitec Pub., 229, 43–54, 2004.
Montagnat, M., Duval, P., Bastie, P., Hamelin, B., Brissaud, O., de Angelis, M., Petit, J.-R., and Lipenkov, V. Y.: High crystalline quality of large single crystals of subglacial ice above lake vostok (antarctica) revealed by hard x-ray diffraction, Comptes Rendus de l'Academie des Sciences – Series IIA – Earth and Planetary Science, 333, 419–425, 2001.
Montagnat, M., Duval, P., Bastie, P., Hamelin, B., and Lipenkov, V. Y.: Lattice distortion in ice crystals from the Vostok core (Antarctica) revealed by hard X-ray diffraction, implication in the deformation of ice at low stresses, Earth Planet. Sc. Lett., 214, 369–378, 2003.
Montagnat, M., Azuma, N., Dahl-Jensen, D., Eichler, J., Fujita, S., Gillet-Chaulet, F., Kipfstuhl, S., Samyn, D., Svensson, A., and Weikusat, I.: Fabric along the NEEM ice core, Greenland, and its comparison with GRIP and NGRIP ice cores, The Cryosphere, 8, 1129–1138, https://doi.org/10.5194/tc-8-1129-2014, 2014.
Montagnat, M., Chauve, T., Barou, F., Tommasi, A., Beausir, B., and Fressengeas, C.: Analysis of dynamic recrystallization of ice from EBSD orientation mapping, Front. Earth Sci., 3, https://doi.org/10.3389/feart.2015.00081, 2015.
Muguruma, J., Mae, S., and Higashi, A.: Void formation by non-basal glide in ice single crystals, Philos. Mag., 13, 625–629, 1966.
Mullins, W. W.: Theory of thermal grooving, J. Appl. Phys., 28, 333–339, 1957.
Nakaya, U.: Mechanical properties of single crystal of ice, Part I. Geometry of deformation, US Army Snow Ice and Permafrost Research Establishment, Research Report 28, 1958.
NEEM community members: Eemian interglacial reconstructed from a greenland folded ice cores, Nature, 493, 489–494, 2013.
Neumann, B.: Texture development of recrystallised quartz polycrystals unravelled by orientation and misorientation characteristics, J. Struct. Geol., 22, 1695–1711, 2000.
Nishida, K. and Narita, H.: Three-dimensional observations of ice crystal characteristics in polar ice sheets, J. Geophys. Res., 101, 21311–21317, 1996.
Obbard, R., Baker, I., and Sieg, K.: Using electron backscatter diffraction patterns to examine recrystallization in polar ice sheets, J. Glaciol., 52, 546–557, 2006.
Oerter, H., Drücker, C., Kipfstuhl, S., and Wilhelms, F.: Kohnen station – the drilling camp for the epica deep ice core in dronning maud land, Polarforschung, 78, 1–23, 2009.
Pauer, F., Kipfstuhl, S., Kuhs, W. F., and Shoji, H.: Air clathrate crystals from the GRIP deep ice core, Greenland: a number-, size- and shape-distribution study, J. Glaciol., 45, 22–30, https://doi.org/10.1017/S0022143000003002, 1999.
Peternell, M., Russell-Head, D. S., and Wilson, C. J. L.: A technique for recording polycrystalline structure and orientation during in situ deformation cycles of rock analogues using an automated fabric analyser, J. Microsc., 242, 181–188, 2010.
Piazolo, S., Montagnat, M., and Blackford, J. R.: Sub-structure characterization of experimentally and naturally deformed ice using cryo-EBSD, J. Microsc., 230, 509–519, 2008.
Prior, D. J., Boyle, A. P., Brenker, F., Cheadle, M. C., Day, A., Lopez, G., Peruzzo, L., Potts, G. J., Reddy, S., Spiess, R., Timms, N. E., Trimby, P., Wheeler, J., and Zetterström, L.: The application of electron backscatter diffraction and orientation contrast imaging in the SEM, to textural problems in rocks, Am. Mineral., 84, 1741–1759, 1999.
Prior, D. J., Wheeler, J., Peruzzo, L., Spiess, R., and Storey, C.: Some garnet microstructures: an illustration of the potential of orientation maps and misorientation analysis in microstructural studies, J. Struct. Geol., 24, 999–1011, 2002.
Prior, D., Lilly, K., Seidemann, M., Vaughan, M., Becroft, L., Easingwood, R., Diebold, S., Obbard, R., Daghlian, C., Baker, I., Caswell, T., Golding, N., Goldsby, D., Durham, W. B., Piazolo, S., and Wilson, C.: Making EBSD on water ice routine, J. Microsc., 259, 237–256, 2015.
Randle, V. and Engler, O.: Introduction to texture analysis: Macrotexture, Microtexture and Orientation Mapping, CRC Press, Taylor & Francis Group, Boca Raton, London, New York, 388 pp., 2000.
Rasmussen, S. O., Abbott, P. M., Blunier, T., Bourne, A. J., Brook, E., Buchardt, S. L., Buizert, C., Chappellaz, J., Clausen, H. B., Cook, E., Dahl-Jensen, D., Davies, S. M., Guillevic, M., Kipfstuhl, S., Laepple, T., Seierstad, I. K., Severinghaus, J. P., Steffensen, J. P., Stowasser, C., Svensson, A., Vallelonga, P., Vinther, B. M., Wilhelms, F., and Winstrup, M.: A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core, Clim. Past, 9, 2713–2730, https://doi.org/10.5194/cp-9-2713-2013, 2013.
Richeton, T., Le, L., Chauve, T., Bernacki, M., Berbenni, S., and Montagnat, M.: Modelling the transport of geometrically necessary dislocations on slip systems: application to single- and multi-crystals of ice, Model. Simul. Mater. Sc., 25, 025010, https://doi.org/10.1088/1361-651X/aa5341, 2017.
Ruth, U., Barnola, J.-M., Beer, J., Bigler, M., Blunier, T., Castellano, E., Fischer, H., Fundel, F., Huybrechts, P., Kaufmann, P., Kipfstuhl, S., Lambrecht, A., Morganti, A., Oerter, H., Parrenin, F., Rybak, O., Severi, M., Udisti, R., Wilhelms, F., and Wolff, E.: “EDML1”: a chronology for the EPICA deep ice core from Dronning Maud Land, Antarctica, over the last 150 000 years, Clim. Past, 3, 475–484, https://doi.org/10.5194/cp-3-475-2007, 2007.
Saylor, D. M. and Rohrer, G. S.: Measuring the Influence of Grain- Boundary Misorientation on Thermal Groove Geometry in Ceramic Polycrystals, J. Am. Ceram. Soc., 82, 1529–1536, 1999.
Schulson, E. M. and Duval, P.: Creep and Fracture of Ice, Cambridge University Press, Cambridge, UK, 2009.
Shearwood, C. and Whitworth, R. W.: The velocity of dislocations in ice, Philos. Mag. A, 64, 289–302, 1991.
Song, M., Baker, I., and Cole, D. M.: The effect of particles on creep rate and microstructures of granular ice, J. Glaciol., 54, 533–537, 2008.
Steinbach, F., Bons, P. D., Griera, A., Jansen, D., Llorens, M.-G., Roessiger, J., and Weikusat, I.: Strain localization and dynamic recrystallization in the ice–air aggregate: a numerical study, The Cryosphere, 10, 3071–3089, https://doi.org/10.5194/tc-10-3071-2016, 2016.
Steinbach, F., Kuiper, E. N., Eichler, J., Bons, P. D., Drury, M. R., Griera, A., Pennock, G. M., and Weikusat, I.: Grain dissection: A new process for grain size reduction in polar ice cores and numerical models, Front. Earth Sci., in press, 2017.
Stocker, T., Dahe, Q., Plattner, G.-K., Tignor, M., Allen, S., and Midgley, P.: Workshop report of the intergovernmental panel on climate change workshop on sea level rise and ice sheet instabilities, available at: www.ipcc-wg1.unibe.ch/meetings/slrisi/slrisi.html (last access: 17 August 2017), 2010.
Suzuki, S.: Grain Coarsening of Microcrystals of Ice. (III), Low Temperature Science Ser. A, 28, 47–61, 1970.
Suzuki, S. and Kuroiwa, D.: Grain-boundary energy and grain-boundary groove angles in ice, J. Glaciol., 11, 265–277, 1972.
Thoma, M., Grosfeld, K., Mayer, C., and Pattyn, F.: Interaction between ice sheet dynamics and subglacial lake circulation: a coupled modelling approach, The Cryosphere, 4, 1–12, https://doi.org/10.5194/tc-4-1-2010, 2010.
Trepied, L., Doukhan, J. C., and Paquet, J.: Subgrain boundaries in quartz theoretical analysis and microscopic observations, Phys. Chem. Miner., 5, 201–218, 1980.
Vaughan, D. and Arthern, R.: Why is it hard to predict the future of ice sheets?, Science, 315, 1503–1504, 2007.
Wei, Y. and Dempsey, J. P.: The motion of non-basal dislocations in ice crystals, Philos. Mag. A, 69, 1–10, 1994.
Wang, Y., Thorsteinsson, T., Kipfstuhl, S., Miller, H., Dahl-Jensen, D., and Shoji, H.: A vertical girdle fabric in the NorthGRIP deep ice core, North Greenland, Ann. Glaciol., 35, 515–520, 2002.
Wegner, A., Fischer, H., Delmonte, B., Petit, J.-R., Erhardt, T., Ruth, U., Svensson, A., Vinther, B., and Miller, H.: The role of seasonality of mineral dust concentration and size on glacial/interglacial dust changes in the EPICA Dronning Maud Land ice core, J. Geophys. Res.-Atmos., 120, 9916–993, 2015.
Wei, Y. and Dempsey, J. P.: The motion of non-basal dislocations in ice crystals, Philos. Mag. A, 69, 1–10, 1994.
Weikusat, C., Freitag, J., and Kipfstuhl, S.: Raman spectroscopy of gaseous inclusions in EDML ice core: First results microbubbles, J. Glaciol., 58, 761–766, 2012.
Weikusat, I., Kipfstuhl, S., Azuma, N., Faria, S. H., and Miyamoto, A.: Deformation Microstructures in an Antarctic Ice Core (EDML) and in Experimentally Deformed Artifcial Ice, in: Physics of Ice Core Records II. Vol. 2 of PICR, edited by: Hondoh, T., Vol. 68, 115–123, 2009a.
Weikusat, I., Kipfstuhl, S., Faria, S. H., Azuma, N., and Miyamoto, A.: Subgrain boundaries and related microstructural features in EPICA Dronning Maud Land (EDML) deep ice core, J. Glaciol., 55, 461–472, 2009b.
Weikusat, I., de Winter, D. A. M., Pennock, G. M., Hayles, M., Schneijdenberg, C. T. W. M., and Drury, M. R.: Cryogenic EBSD on ice: preserving a stable surface in a low pressure SEM, J. Microsc., 242, 295–310, 2010.
Weikusat, I., Miyamoto, A., Faria, S. H., Kipfstuhl, S., Azuma, N., and Hondoh, T.: Subgrain boundaries in Antarctic ice quantified by X-ray Laue diffraction, J. Glaciol., 57, 85–94, 2011.
Weikusat, I., Lambrecht, A., and Kipfstuhl, S.: Eigenvalues of crystal orientation tensors for c-axes distributions of vertical thin sections from the EDML ice core, https://doi.org/10.1594/PANGAEA.807142, 2013.
Weikusat, I., Kuiper, E.-J. N., Pennock, G. M., Kipfstuhl, S., and Drury, M. R.: EBSD analysis of subgrain boundaries and dislocation slip systems in Antarctic and Greenland ice, PANGAEA, https://doi.org/10.1594/PANGAEA.879614, 2017a.
Weikusat, I., Jansen, D., Binder, T., Eichler, J., Faria, S. H., Wilhelms, F., Kipfstuhl, S., Sheldon, S., Miller, H., Dahl-Jensen, D., and Kleiner, T.: Physical analysis of an Antarctic ice core – towards an integration of micro- and macrodynamics of polar ice, Philos. T. R. Soc. Lond. A, 375, 20150347, https://doi.org/10.1098/rsta.2015.0347, 2017b.
Weertman, J. and Weertman, J. R.: Elementary Dislocation Theory, Oxford University Press, UK, 231 pp., 1992.
Wesche, C., Eisen, O., Oerter, H., Schulte, D., and Steinhage, D.: Surface topography and ice flow in the vicinity of the EDML deep-drilling site, Antarctica, J. Glaciol., 53, 442–448, 2007.
Wilhelms, F., Sheldon, S. G., Hamann, I., and Kipfstuhl, S.: Implications for and findings from deep ice core drillings – An example: The ultimate tensile strength of ice at high strain rates, Physics and Chemistry of Ice, The proceedings of the International Conference on the Physics and Chemistry of Ice held at Bremerhaven, Germany, 23–28 July 2006, 635–639, 2007.
Wilhelms, F., Miller, H., Gerasimoff, M. D., Drücker, C., Frenzel, A., Fritzsche, D., Grobe, H., Hansen, S. B., Hilmarsson, S. Æ., Hoffmann, G., Hörnby, K., Jaeschke, A., Jakobsdóttir, S. S., Juckschat, P., Karsten, A., Karsten, L., Kaufmann, P. R., Karlin, T., Kohlberg, E., Kleffel, G., Lambrecht, A., Lambrecht, A., Lawer, G., Schärmeli, I., Schmitt, J., Sheldon, S. G., Takata, M., Trenke, M., Twarloh, B., Valero-Delgado, F., and Wilhelms-Dick, D.: The EPICA Dronning Maud Land deep drilling operation Ann. Glaciol., 55, 355–366, 2014.
Wilson, C., Burg, J., and Mitchell, J.: The origin of kinks in polycrystalline ice, Tectonophysics, 127, 27–48, 1986.
Wolovick, M. J. and Creyts, T. T.: Overturned folds in ice sheets: Insights from a kinematic model of traveling sticky patches and comparisons with observations, J. Geophys. Res.-Earth, 121, 1065–108, 2016.
Short summary
Understanding the flow of large ice masses on Earth is a major challenge in our changing climate. Deformation mechanisms are governed by the strong anisotropy of ice. As anisotropy is currently moving into the focus of ice sheet flow studies, we provide a detailed analysis of microstructure data from natural ice core samples which directly relate to anisotropic plasticity. Our findings reveal surprising dislocation activity which seems to contradict the concept of macroscopic ice anisotropy.
Understanding the flow of large ice masses on Earth is a major challenge in our changing...
