Filtering by Subject: Glaciology

Ascent rates of 3D fractures driven by a finite batch of buoyant fluid

Timothy Davis, Eleonora Rivalta, Delphine Smittarello, et al.

Published: 2022-06-20
Subjects: Fluid Dynamics, Geology, Glaciology, Mechanics of Materials, Volcanology

Propagation of fluid-filled fractures by fluid buoyancy is important in a variety of settings, from magmatic dykes and veins to water-filled crevasses in glaciers. Industrial hydro-fracturing utilises fluid-driven fractures to increase the permeability of rock formations; the effect of buoyancy on fracture pathways in this context is typically neglected. Analytical approximations for the buoyant [...]

Surging vs. streaming: the dual fast ice flow response to variations in efficiency of the subglacial drainage landsystem

Ravier Edouard, Thomas Lelandais, Jean Vérité, et al.

Published: 2022-05-24
Subjects: Geomorphology, Glaciology

Observation and modelling have long contributed to associate surging and streaming of glaciers with glacier thermal regime, variations in meltwater availability and pressure and mechanical coupling at their beds. Using experimental modelling and palaeoglaciological mapping, we explore how the development of subglacial drainage landsystems controls variations in drainage efficiency and ice flow [...]

Complex motion of Greenland Ice Sheet outlet glaciers with basal temperate ice

Robert Law, Poul Christoffersen, Emma MacKie, et al.

Published: 2022-05-19
Subjects: Glaciology

Uncertainty associated with ice motion plagues sea-level rise predictions. Much of this uncertainty arises from imperfect representations of physical processes including basal slip and internal ice deformation, with ice-sheet models largely incapable of reproducing borehole-based observations. To investigate further, we model isolated 3D domains from fast-moving (Sermeq Kujalleq or Store Glacier) [...]

The CREp 36Cl exposure age calculator: development version “dev”

Irene Schimmelpfennig, Pierre-Henri BLARD, Jim Tesson, et al.

Published: 2022-05-04
Subjects: Geochemistry, Geology, Geomorphology, Glaciology, Sedimentology, Tectonics and Structure, Volcanology

Chlorine-36 (36Cl) is currently the only in situ cosmogenic nuclide applicable in carbonates, Ca- and K-rich feldspars and aphyric silicate rocks. Because the production reactions of 36Cl are more numerous and complex than those of other cosmogenic nuclides (e.g. 10Be, 3He), comprehensive and user-friendly calculators are essential for routine application of 36Cl to Earth surface research [...]

Late Glacial and Holocene Palaeolake History of the Última Esperanza Region of Southern Patagonia

Stephen J Roberts, Robert D McCulloch, Joseph F Emmings, et al.

Published: 2022-03-29
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Glaciology, Hydrology, Paleobiology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology

We undertook multiproxy analyses on two sediment cores from Lago Pato, a small lake basin at 51°S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake level change in the TdP and Última Esperanza region over the last ~30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Icefield [...]

Strain localisation and microstructure evolution in polycrystalline ice by in-situ strain field measurements

Marco Antonio Lopez-Sanchez, Thomas Chauve, Maurine Montagnat, et al.

Published: 2022-03-28
Subjects: Earth Sciences, Glaciology, Tectonics and Structure

We explore the links between the evolutions of the strain field and microstructure in coarse-grained Ih ice. Using digital image correlation (DIC), we monitored the evolution of the strain field in two columnar ice samples deformed by creep (uniaxial compression at constant load) at -7 ºC and 0.5 MPa up to 9.5% bulk shortening. After a brief transient (<0.2% bulk strain), in which strain [...]

Greenland ice sheet vulnerability under diverse climatic warming scenarios

Benjamin Andrew Keisling, Joerg M. Schaefer, Robert DeConto, et al.

Published: 2022-03-26
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Sea-level rise of even one meter will have drastic global impacts. Melting the Greenland Ice Sheet (GIS) would raise sea level by 7.4 meters. There is an urgent need to improve predictions of how quickly the GIS will contribute its first meter of sea-level rise, and from where on the ice sheet that water will come. Estimating the volume of Greenland ice that was lost during past warm periods [...]

Meltwater generation in ice stream shear margins: case study in Antarctic ice streams

Meghana Ranganathan, Jack-William Barotta, Colin R. Meyer, et al.

Published: 2022-01-05
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Liquid water within glacier ice and at the glacier beds exerts a significant control on ice flow and glacier stability through a number of processes, including altering the rheology of the ice and lubricating the bed. Some of this water is generated as melt in regions of rapid deformation, including shear margins, due to heating by viscous dissipation. However, how much meltwater is generated and [...]

Streamlined subglacial bedform sensitivity to bed characteristics across the deglaciated Northern Hemisphere

Marion A. McKenzie, Lauren Miller Simkins, Sarah Principato

Published: 2021-11-10
Subjects: Earth Sciences, Geology, Geomorphology, Glaciology

Streamlined subglacial bedforms observed in deglaciated landscapes provide the opportunity to assess the sensitivity of glacier dynamics to bed characteristics across broader spatiotemporal scales than is possible for contemporary glacial systems. While many studies of streamlined subglacial bedforms rely on manual mapping and qualitative (i.e., visual) assessment, we semi-automatically identify [...]

Persistent shallow micro-seismicity at Llaima volcano, Chile, with implications for long-term monitoring

Oliver Lamb, Jonathan M Lees, Luis Franco Marin, et al.

Published: 2021-11-01
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics, Volcanology

Identifying the source mechanisms of low-frequency earthquakes at ice-covered volcanoes can be challenging due to overlapping characteristics of glacially and magmatically derived seismicity. Here we present an analysis of two months of seismic data from Llaima volcano, Chile, recorded by the permanent monitoring network in 2019. We find over 2,000 repeating low-frequency events split across 82 [...]

Reproducibility in subsurface geoscience

Michael J. Steventon, Chris Jackson, Mark Ireland, et al.

Published: 2021-10-27
Subjects: Biogeochemistry, Cosmochemistry, Earth Sciences, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Geochemistry, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Hydrology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Paleobiology, Paleontology, Sedimentology, Soil Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Reproducibility, the extent to which consistent results are obtained when an experiment or study is repeated, sits at the foundation of science. The aim of this process is to produce robust findings and knowledge, with reproducibility being the screening tool to benchmark how well we are implementing the scientific method. However, the re-examination of results from many disciplines has caused [...]

Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet

Allie Balter-Kennedy, Nicolás E. Young, Jason P. Briner, et al.

Published: 2021-08-31
Subjects: Earth Sciences, Geochemistry, Geomorphology, Glaciology

Erosion beneath glaciers and ice sheets is a fundamental Earth-surface process dictating landscape development, which in turn influences ice-flow dynamics and the climate sensitivity of ice masses. The rate at which subglacial erosion takes place, however, is notoriously difficult to observe because it occurs beneath modern glaciers in a largely inaccessible environment. Here, we present 1) [...]

Safety and Belonging in the Field: A Checklist for Educators

Sarah E Greene, Gwen S. Antell, Jake Atterby, et al.

Published: 2021-08-19
Subjects: Atmospheric Sciences, Biogeochemistry, Climate, Cosmochemistry, Earth Sciences, Education, Environmental Education, Environmental Health and Protection, Environmental Indicators and Impact Assessment, Environmental Monitoring, Environmental Sciences, Environmental Studies, Fresh Water Studies, Geochemistry, Geographic Information Sciences, Geography, Geology, Geomorphology, Geophysics and Seismology, Glaciology, Higher Education, Human Geography, Hydrology, Life Sciences, Meteorology, Mineral Physics, Natural Resource Economics, Natural Resources and Conservation, Natural Resources Management and Policy, Nature and Society Relations, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Other Geography, Other Oceanography and Atmospheric Sciences and Meteorology, Other Planetary Sciences, Outdoor Education, Paleobiology, Paleontology, Physical and Environmental Geography, Physical Sciences and Mathematics, Planetary Biogeochemistry, Planetary Geochemistry, Planetary Geology, Planetary Geomorphology, Planetary Geophysics and Seismology, Planetary Glaciology, Planetary Hydrology, Planetary Mineral Physics, Planetary Sciences, Planetary Sedimentology, Remote Sensing, Sedimentology, Social and Behavioral Sciences, Soil Science, Spatial Science, Speleology, Stratigraphy, Sustainability, Tectonics and Structure, Volcanology, Water Resource Management

Ensuring taught fieldwork is a positive, generative, collective, and valuable experience for all participants requires considerations beyond course content. To guarantee safety and belonging, participants’ identities (backgrounds and protected characteristics) must be considered as a part of fieldwork planning and implementation. Furthermore, getting fieldwork right is an important step in [...]

Ice viscosity is more sensitive to stress than commonly assumed

Joanna Millstein, Brent Minchew, Samuel S Pegler

Published: 2021-08-12
Subjects: Glaciology

Accurate representation of the viscous flow of ice is fundamental to understanding glacier dynamics and projecting sea-level rise. Ice viscosity is often described by a simple but largely untested and uncalibrated constitutive relation, Glen’s Flow Law, wherein the rate of deformation is proportional to stress raised to the power n. The value n = 3 is commonly prescribed in ice-flow models, [...]

The impact of spatially varying ice sheet basal conditions on sliding at glacial time scales

Evan James Gowan, Sebastian Hinck, Lu Niu, et al.

Published: 2021-07-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics

Spatially variable bed conditions govern how ice sheets behave at glacial time scales (>1000 years). The presence or lack of complete sediment cover is responsible for changes in dynamics between the core and peripheral regions of the Laurentide and Fennoscandian ice sheets. A key component of this change is because sliding is promoted when unconsolidated sediments below the ice become water [...]


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