Ilka Weikusat
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View article: Folding due to anisotropy in ice, from drill-core-scale cloudy bands to km-scale internal reflection horizons
Folding due to anisotropy in ice, from drill-core-scale cloudy bands to km-scale internal reflection horizons Open
Upright folds in ice sheets are observed on the cm scale in cloudy bands in drill cores and on the km scale in radargrams. We address the question of the folding mechanism for these folds by analysing the power spectra of fold trains to ob…
View article: Air clathrate hydrates in the EDML ice core, Antarctica
Air clathrate hydrates in the EDML ice core, Antarctica Open
In the deeper part of polar ice sheets, air hydrates trap most of the ancient air molecules, which are essential for understanding past climate. We use digital image analysis to create a high-resolution record of air hydrate number, size, …
View article: Microstructure and ice dynamics – Integrating Grain Properties, Fabric, and Borehole Data in the NEEM Ice Core
Microstructure and ice dynamics – Integrating Grain Properties, Fabric, and Borehole Data in the NEEM Ice Core Open
The physical properties of ice grains, including grain size and orientation, are fundamental to understanding ice flow and deformation processes in polar ice sheets. This study leverages a newly developed large-area scanning microscope (xL…
View article: Linking crystallographic orientation and ice stream dynamics: evidence from the EastGRIP ice core
Linking crystallographic orientation and ice stream dynamics: evidence from the EastGRIP ice core Open
A better understanding of glacial ice flow and how it is influenced by internal deformation is required to improve the projections of future sea level rise under a warming climate. Large ice streams, the main contributors to solid-ice disc…
View article: Physical properties in the shear margin of the Northeast Greenland Ice Stream
Physical properties in the shear margin of the Northeast Greenland Ice Stream Open
The North-East Greenland Ice Stream (NEGIS) is a major contributor to ice loss experienced by the Greenland Ice Sheet. Our current understanding of the mechanics of this highly dynamic feature is limited compared to the surrounding slowly …
View article: Cryo-SEM and EBSD on air clathrate hydrates in polar ice
Cryo-SEM and EBSD on air clathrate hydrates in polar ice Open
In the deeper part of polar ice sheets, air clathrate hydrates (commonly referred to as air hydrates) trap most of the ancient air molecules in their crystal structure, which is the only direct paleo-atmosphere access used for paleoclimati…
View article: Air clathrate hydrates in the EDML ice core, Antarctica
Air clathrate hydrates in the EDML ice core, Antarctica Open
In the deeper part of polar ice sheets, air hydrates trap most of the ancient air molecules, which are essential for understanding past climate. We use digital image analysis to create a high-resolution record of air hydrate number, size a…
View article: How to make an ice stream
How to make an ice stream Open
Fast-flowing ice streams drain most of the inland ice from the Antarctic and Greenland ice sheets. Despite their critical role, the formation mechanisms of ice streams and their shear margins remain controversial. We present a three-dimens…
View article: Folding due to anisotropy in ice, from drill core-scale cloudy bands to km-scale internal reflection horizons
Folding due to anisotropy in ice, from drill core-scale cloudy bands to km-scale internal reflection horizons Open
Upright folds in ice sheets are observed on the cm-scale in cloudy bands in drill cores and on the km-scale in radargrams. We address the question of the folding mechanism for these folds, by analysing the power spectra of fold trains to o…
View article: EastGRIP ice core reveals the exceptional evolution of crystallographic preferred orientation throughout the Northeast Greenland Ice Stream
EastGRIP ice core reveals the exceptional evolution of crystallographic preferred orientation throughout the Northeast Greenland Ice Stream Open
A better understanding of glacial ice flow and how it is influenced by internal deformation is required to improve the projections of future sea-level rise in a warming climate. Especially large ice streams, the main contributors to solid …
View article: Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores – results from the EastGRIP region
Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores – results from the EastGRIP region Open
We investigate the lock-in zone (LIZ) of the East Greenland Ice Core Project (EastGRIP) region, northeastern Greenland, in detail. We present results from the firn air-pumping campaign of the S6 borehole, forward modeling, and a novel tech…
View article: Formation Mechanisms of Large‐Scale Folding in Greenland's Ice Sheet
Formation Mechanisms of Large‐Scale Folding in Greenland's Ice Sheet Open
Radio‐echo sounding (RES) shows large‐scale englacial stratigraphic folds are ubiquitous in Greenland's ice sheet. However, there is no consensus yet on how these folds form. Here, we use the full‐Stokes code Underworld2 to simulate ice mo…
View article: Folded ice in the upper North East Greenland Ice Stream reveal timing of the onset of streaming
Folded ice in the upper North East Greenland Ice Stream reveal timing of the onset of streaming Open
Only a few localised ice streams drain most ice from the Greenland Ice Sheet. Thus, understanding ice stream behaviour and their temporal variability is crucially important to predict future sea-level change. The interior trunk of the 700 …
View article: Duplex Structures in the EastGRIP Ice Core - the Loss of Stratigraphic Integrity
Duplex Structures in the EastGRIP Ice Core - the Loss of Stratigraphic Integrity Open
The EastGRIP ice core is drilled through the Northeast Greenland Ice Stream, which has a surface velocity of 55 m/yr towards NNE at the drill site. Deriving a better understanding of internal deformation and the rheology within an ice…
View article: Air clathrate hydrates of the Antarctic EPICA Dronning Maud Land ice core
Air clathrate hydrates of the Antarctic EPICA Dronning Maud Land ice core Open
Polar ice cores are a unique climate archive as they provide the most direct record of past atmospheric gas compositions. In the deeper part of polar ice sheets, most of the ancient air molecules are stored in the crystal lattice of clathr…
View article: A structural geologist's view on the Northeast Greenland Ice Stream
A structural geologist's view on the Northeast Greenland Ice Stream Open
The Northeast Greenland Ice Stream (NEGIS) is a fascinating, over 500 km long structure in the Greenland Ice Sheet. The ice stream shows many features, such as folds and shear zones, that are also common in other ductile rocks. Geological …
View article: Deformation and recrystallization inside the Northeast Greenland Ice Stream – findings from microstructural analysis of the EastGRIP ice core
Deformation and recrystallization inside the Northeast Greenland Ice Stream – findings from microstructural analysis of the EastGRIP ice core Open
Solid ice discharge from land-based ice masses into the ocean raises the global sea level and accelerates due to anthropogenic climate change. Modelling ice flow dynamics aims to provide better projections of future sea level rise. The Ant…
View article: Shear margins in upper half of Northeast Greenland Ice Stream were established two millennia ago
Shear margins in upper half of Northeast Greenland Ice Stream were established two millennia ago Open
Only a few localised ice streams drain most of the ice from the Greenland Ice Sheet. Thus, understanding ice stream behaviour and its temporal variability is crucially important to predict future sea-level change. The interior trunk of the…
View article: Ice Modeling Indicates Formation Mechanisms of Large-scale Folding in Greenland's Ice Sheet
Ice Modeling Indicates Formation Mechanisms of Large-scale Folding in Greenland's Ice Sheet Open
Radio-echo sounding (RES) has shown that large-scale folds in the englacial stratigraphy is ubiquitous in Greenland’s ice sheet. However, there is no consensus yet on how these folds form. Here, we use the full-Stokes code Underworld2 to s…
View article: Bridging the Gap Between Experimental and Natural Fabrics: Modeling Ice Stream Fabric Evolution and its Comparison With Ice‐Core Data
Bridging the Gap Between Experimental and Natural Fabrics: Modeling Ice Stream Fabric Evolution and its Comparison With Ice‐Core Data Open
Fabrics, also known as textures or crystallographic preferred orientations, reveal information about the deformation history of the flow of polycrystalline materials, including glacial ice, olivine in the mantle, and feldspar and quartz in…
View article: Comment on egusphere-2023-1904
Comment on egusphere-2023-1904 Open
Abstract. We investigate the lock-in zone (LIZ) of the EastGRIP region, Northeast Greenland, in detail. We present results from the firn air pumping campaign of the S6 borehole, forward modeling, and a novel technique for finding the lock-…
View article: Clathrate hydrates of air in polar ice and their importance for climate science
Clathrate hydrates of air in polar ice and their importance for climate science Open
clathrate hydrates are solid guest-host com- pounds, formed by small molecules (guests; e.g. N2, O2, cH4 or cO2) trapped in a crystal- line framework (host) of hydrogen-bonded water molecules (chazallon and Kuhs 2002). In natural environme…
View article: Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores - results from the EastGRIP region
Combining traditional and novel techniques to increase our understanding of the lock-in depth of atmospheric gases in polar ice cores - results from the EastGRIP region Open
We investigate the lock-in zone (LIZ) of the EastGRIP region, Northeast Greenland, in detail. We present results from the firn air pumping campaign of the S6 borehole, forward modeling, and a novel technique for finding the lock-in depth (…
View article: The new frontier of microstructural impurity research in polar ice
The new frontier of microstructural impurity research in polar ice Open
Deciphering the localisation of solid and dissolved impurities on the micron-scale in glacial ice remains a challenge, but is critical to understand the integrity of ice core records and internal deformation. Here we report on the state-of…
View article: C-axis data from 3 depths at EGRIP
C-axis data from 3 depths at EGRIP Open
C-axis data as azimuth and latitude in degrees, from 3 depths at EGRIP: 145.93m, 1048.3m, 1449.07m
View article: C-axis data from 3 depths at EGRIP
C-axis data from 3 depths at EGRIP Open
C-axis data as azimuth and latitude in degrees, from 3 depths at EGRIP: 145.93m, 1048.3m, 1449.07m
View article: Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within
Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within Open
Impurities in polar ice play a critical role in ice flow, deformation, and the integrity of the ice core record. Especially cloudy bands, visible layers with high impurity concentrations, are prominent features in ice from glacial periods.…
View article: Supporting data for manuscript "Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within "
Supporting data for manuscript "Chemical and visual characterisation of EGRIP glacial ice and cloudy bands within " Open
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers micron-resolution 2D chemical imaging, which has been adapted recently to ice core analysis. The datasets are supporting information for the manuscript "Chemica…