Preprints
Filtering by Subject: Glaciology
Meltwater generation in ice stream shear margins: case study in Antarctic ice streams
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
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
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
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
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
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
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
Published: 2021-07-28
Subjects: Earth Sciences, Glaciology, Physical Sciences and Mathematics
Spatially variable basal conditions are thought to govern how ice sheets behave at glacial time scales (>1000 years) and responsible for changes in dynamics between the core and peripheral regions of the Laurentide and Fennoscandian ice sheets. Basal motion is accomplished via the deformation of unconsolidated sediments, or via sliding of the ice over an undeformable bed. We present an ice sheet [...]
Melting temperature changes during slip across subglacial cavities drive basal mass exchange
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
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
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
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
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
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
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 [...]