Preprints

Filtering by Subject: Glaciology

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 [...]

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 ice 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: 2021-10-26
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 [...]

Reassessing the flow law of glacier ice using satellite observations

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 [...]

Melting temperature changes during slip across subglacial cavities drive basal mass exchange

Alan Rempel, Colin R. Meyer, Kiya Riverman

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

The importance of glacier sliding has motivated a rich literature describing the thermomechanical interactions between ice, liquid water, and bed materials. Early recognition of the gradient in melting temperature across small bed obstacles led to focussed studies of regelation. An appreciation for the limits on ice deformation rates downstream of larger obstacles highlighted a role for [...]

Water flow through sediments and at the ice-sediment interface beneath Sermeq Kujalleq (Store Glacier), Greenland

Samuel Huckerby Doyle, Bryn Hubbard, Poul Christoffersen, et al.

Published: 2021-07-05
Subjects: Earth Sciences, Glaciology

Subglacial hydrology modulates basal motion but remains poorly constrained, particularly for soft-bedded Greenlandic outlet glaciers. Here, we report detailed measurements of the response of subglacial water pressure to the connection and drainage of adjacent water-filled boreholes drilled through kilometre-thick ice on Sermeq Kujalleq (Store Glacier). These measurements provide evidence for gap [...]

Cosmogenic 3He in terrestrial rocks: a review

Pierre-Henri BLARD

Published: 2021-07-05
Subjects: Earth Sciences, Geochemistry, Geology, Geomorphology, Glaciology, Other Earth Sciences

This review article summarizes the state of the art of cosmogenic 3He (3Hec), with a focus on the most efficient methods and strategies for measuring this cosmogenic noble gas in the terrestrial minerals. Our ability to accurately and precisely measure cosmogenic 3He in minerals is mainly constrained by the level of the non-cosmogenic 3He background (i.e., magmatic, radiogenic, nucleogenic, and [...]

A Model Workflow for GeoDeepDive: Locating Pliocene and Pleistocene Ice-Rafted Debris

Simon Goring, Jeremiah Marsicek, Shan Ye, et al.

Published: 2021-07-02
Subjects: Earth Sciences, Glaciology, Sedimentology

Machine learning technology promises a more efficient and scalable approach to locating and aggregating data and information from the burgeoning scientific literature. Realizing this promise requires provision of applications, data resources, and the documentation of analytic workflows. GeoDeepDive provides a digital library comprising over 13 million peer-reviewed documents and the computing [...]

C:N:P stoichiometry in six distinct habitats of a glacier terminus in the Yangtze River Source Area

Ze Ren, Hongkai Gao, Wei Luo, et al.

Published: 2021-07-01
Subjects: Biogeochemistry, Earth Sciences, Ecology and Evolutionary Biology, Environmental Sciences, Glaciology, Life Sciences, Other Environmental Sciences, Sustainability

Glaciers are among the least explored environments on Earth, especially from a perspective of nutrient stoichiometry. In this study, we documented and compared the nutrient availabilities (concentrations) and composition (stoichiometric ratios) of nutrients (C, N, and P) in six distinct habitats of a glacier terminus in the Yangtze River Source area, including surface ice (SI), basal ice (BI), [...]

Deglaciation-enhanced mantle CO2 fluxes at Yellowstone imply positive climate feedback

Fiona Clerc, Mark Behn, Brent Minchew

Published: 2021-06-25
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Glaciology, Tectonics and Structure, Volcanology

The generation of mantle melts in response to decompression by glacial unloading has been linked to enhanced volcanic activity and volatile release in Iceland and in global eruptive records. However, it is unclear whether this process is also important in magmatically-active systems that do not show evidence of enhanced eruption rates. For example, the deglaciation of the Yellowstone ice cap did [...]

A fully-coupled 3D model of a large Greenlandic outlet glacier with evolving subglacial hydrology, frontal plume melting and calving

Samuel James Cook, Poul Christoffersen, Joe Todd

Published: 2021-06-25
Subjects: Glaciology

We present the first fully coupled 3D full-Stokes model of a tidewater glacier, incorporating ice flow, subglacial hydrology, plume-induced frontal melting and calving. We apply the model to Store Glacier (Sermeq Kujalleq) in west Greenland to simulate a year of high melt (2012) and one of low melt (2017). In terms of modelled hydrology, we find perennial channels extending 5 km inland from the [...]

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