USAP-DC

{"dp_type": "Dataset", "free_text": "Porosity"}

[{"awards": "2149518 Fudge, Tyler; 2019719 Brook, Edward", "bounds_geometry": ["POINT(159.356 -76.73)"], "date_created": "Fri, 19 Dec 2025 00:00:00 GMT", "description": "These data cover four depth regimes from the ALHIC1901 core from the Allan Hills Blue Ice Area, Antarctica. We derived crystal properties such as grain size and preferred orientation of the c-axis (fabric) via an Automated Fabric Analyser (G50 by Russelhead Instruments). These data are useful for understanding the current deformation at the ALHIC1901 site impacting the preserved climate record.", "east": 159.356, "geometry": ["POINT(159.356 -76.73)"], "keywords": "Air Bubbles; Allan Hills; Antarctica; Bubble Number Density; Cryosphere; Ice Deformation; Microstructure; Porosity", "locations": "Antarctica; Allan Hills", "north": -76.73, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "persons": "Stoll, Nicolas", "project_titles": "Center for Oldest Ice Exploration; Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}, {"proj_uid": "p0010365", "repository": "USAP-DC", "title": "Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -76.73, "title": "Allan Hills ALHIC1901 ice core fabric data", "uid": "602011", "west": 159.356}, {"awards": "2019719 Brook, Edward; 2149518 Fudge, Tyler", "bounds_geometry": ["POINT(159.356 -76.73)"], "date_created": "Fri, 19 Dec 2025 00:00:00 GMT", "description": "These data cover four depth regimes from the ALHIC1901 core from the Allan Hills Blue Ice Area, Antarctica. We derived several 2D bubble characteristics from analysing stinted images of ice sample thin sections, such as bubble size and elongation (aspect ratio) These data are useful for understanding the current deformation at the ALHIC1901 site impacting the preserved climate record.", "east": 159.356, "geometry": ["POINT(159.356 -76.73)"], "keywords": "Air Bubbles; Allan Hills; Antarctica; Bubble Number Density; Cryosphere; Ice Deformation; Microstructure; Porosity", "locations": "Allan Hills; Antarctica", "north": -76.73, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "persons": "Stoll, Nicolas; Fudge, T. J.", "project_titles": "Center for Oldest Ice Exploration; Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}, {"proj_uid": "p0010365", "repository": "USAP-DC", "title": "Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -76.73, "title": "Allan Hills ALHIC1901 ice core 2D bubble parameters", "uid": "602010", "west": 159.356}, {"awards": "2019719 Brook, Edward; 2149518 Fudge, Tyler", "bounds_geometry": ["POINT(159.356 -76.73)"], "date_created": "Fri, 19 Dec 2025 00:00:00 GMT", "description": "These data cover several depth regimes from the ALHIC1901 core from the Allan Hills Blue Ice Area, Antarctica. We derived several bubble characteristics from 3D Computer Tomography analysis, such as bubble size, elongation (aspect ratio), number density and porosity. These data are useful for understanding the current deformation at the ALHIC1901 site impacting the preserved climate record.", "east": 159.356, "geometry": ["POINT(159.356 -76.73)"], "keywords": "Air Bubbles; Allan Hills; Antarctica; Bubble Number Density; Cryosphere; Ice Deformation; Microstructure; Porosity", "locations": "Antarctica; Allan Hills", "north": -76.73, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "persons": "Stoll, Nicolas; Freitag, Johannes", "project_titles": "Center for Oldest Ice Exploration; Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections", "projects": [{"proj_uid": "p0010321", "repository": "USAP-DC", "title": "Center for Oldest Ice Exploration"}, {"proj_uid": "p0010365", "repository": "USAP-DC", "title": "Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "COLDEX", "south": -76.73, "title": "Allan Hills ALHIC1901 ice core 3D bubble parameters", "uid": "602009", "west": 159.356}, {"awards": null, "bounds_geometry": null, "date_created": "Fri, 12 Dec 2025 00:00:00 GMT", "description": "The spatial variability of firn properties, including microstructure, is critical for mass-balance estimates and ice- core interpretations. This includes local and regional variations in firn microstructure, which influence compaction and air movement in the firn. Some of the oldest ice cores are located in blue-ice areas and originated from low-accumulation areas. Surface processes, including small variations in surface conditions and topography, may cause significant alteration of the firn microstructure and bulk firn properties in low-accumulation areas, as firn may interact with surface processes for long periods of time (e.g., hundreds of years). Here, we examine the impact of very low-accumulation rates (A = O(10\u22123 \u2212 10\u22122 m/a)) on firn microstructure using micro-computed tomography data from a firn core (PICO2303) retrieved in the accumulation zone at Allan Hills Blue Ice Area (BIA), Antarctica during the 2023-2024 NSF-COLDEX field season. First, we analyze microstructural parameters such as total porosity, density, specific surface area, degree of anisotropy, and structure thickness, as well as 2D and 3D reconstructed digital datasets. Subsequently, we compare our observations with a firn core from Dadic et al. (2015) that we refer to here as AHMIF, and located \u223c9 km downslope. In the PICO2303 core, we find 1) faceted grains, 2) wind crusts, 3) vertically oriented networks, and 4) specific surface area of 1.5 m^2/kg greater and density of 205 kg/m^3 lower below the surface compared to those measured in the AHMIF core. We propose that these characteristics are a result of differences in both surface processes (e.g., formation and decay of sastrugi) and subsurface evolution (e.g., depth-hoar formation) that likely occur at varying degrees.", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": null, "nsf_funding_programs": null, "persons": "Horlings, B. Ilyse", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": null, "title": "Firn microstructure from micro-computer tomography of PICO2303, Allan Hills Blue Ice Area, Antarctica", "uid": "602002", "west": null}, {"awards": "1935438 McCarthy, Christine", "bounds_geometry": null, "date_created": "Tue, 27 May 2025 00:00:00 GMT", "description": "This archive contains data from temperature-controlled, uniaxial compaction experiments on synthetic firn samples. Synthetic firn samples with a diameter of 1 in and a height of ~45 mm were created from seed ice that was prepared following the standard ice method. Sample fabrication took place in a cold room with a temperature of -25\u00b0C to -20\u00b0C, where the seed ice was mechanically crushed and sieved to a grain size of 210 - 500 microns.\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eThe experiments were conducted in an apparatus that allows for: control of axial loads up to 3.5 MPa with a precision of 0.1 kPa, measurement of axial displacement with a precision of 1 micron, and control of sample temperatures down to -40\u00b0C with a precision of 0.05\u00b0C. Each experiment was conducted at a constant temperature and targeted axial stress. Samples were compacted uniaxially for about week. The archive contains data from 21 experiments: at four target stresses (0.5 MPa, 1 MPa, 2 MPa, and 3.4 MPa) and five different temperatures (-40\u00b0C, -30\u00b0C, -20\u00b0C, -10\u00b0C, and -2\u00b0C) at each target stress. Plus an additional experiment at 1 MPa and T = -10\u00b0C.\r\n\u003cbr/\u003e\r\n\u003cbr/\u003eThree sets of data are provided for each experiment. (I) Mechanical data recorded at 1 Hz: axial displacement, sample height, density, porosity, target stress, seal stress, and applied stress. (II) Strain rates computed over a subset of the mechanical data. (III) Data from grain size analysis conducted on samples after compaction. The grain size data includes five optical microscopy images from each sample and measurements of grain sizes from those images.\r\n\u003cbr/\u003e\r\n\u003cbr/\u003e", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere; Firn; Firn Density", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Skarbek, Rob; Houdyshell, Kris; McCarthy, Christine M.", "project_titles": "Understanding Firn Rheology Through Laboratory Compaction Experiments and Radar Data", "projects": [{"proj_uid": "p0010185", "repository": "USAP-DC", "title": "Understanding Firn Rheology Through Laboratory Compaction Experiments and Radar Data"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Mechanical and Grain Size Data from Constant Stress Uniaxial Compaction Experiments on Synthetic Firn", "uid": "601937", "west": null}, {"awards": "1543537 Priscu, John", "bounds_geometry": ["POINT(-149.50134 -84.640287)"], "date_created": "Wed, 01 Feb 2023 00:00:00 GMT", "description": "This dataset contains bulk sediment properties measurements from cores collected from Mercer Subglacial Lake by the SALSA project. Included are: physical properties (bulk density, mass water content, porosity, shear strength, particle size distribution, and mineralogy); carbon (inorganic and organic); iron (ascorbate- and dithionite-extractable); and sulfur (acid-volatile and chromium-reducible).", "east": -149.50134, "geometry": ["POINT(-149.50134 -84.640287)"], "keywords": "Antarctica; Carbon; Glacier; Glaciers/ice Sheet; Glaciers/Ice Sheet; Iron; Mercer Subglacial Lake; Mineralogy; Particle Size; Physical Properties; SALSA; Sediment Core; Sulfur; West Antarctic Ice Sheet", "locations": "Mercer Subglacial Lake; Mercer Subglacial Lake; Antarctica; West Antarctic Ice Sheet", "north": -84.640287, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Dore, John; Campbell, Timothy; Michaud, Alexander; Hawkings, Jon; Skidmore, Mark; Tranter, Martyn; Venturelli, Ryan A; Science Team, SALSA", "project_titles": "Collaborative Research: Subglacial Antarctic Lakes Scientific Access (SALSA): Integrated Study of Carbon Cycling in Hydrologically-active Subglacial Environments", "projects": [{"proj_uid": "p0010119", "repository": "USAP-DC", "title": "Collaborative Research: Subglacial Antarctic Lakes Scientific Access (SALSA): Integrated Study of Carbon Cycling in Hydrologically-active Subglacial Environments"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -84.640287, "title": "Discrete bulk sediment properties data from Mercer Subglacial Lake", "uid": "601661", "west": -149.50134}, {"awards": "1043528 Alley, Richard", "bounds_geometry": ["POINT(-112.085 -79.467)"], "date_created": "Tue, 16 Jan 2018 00:00:00 GMT", "description": "This dataset includes all surface, snowpit, crust, AWS, and near-surface thermistor data used for analyses and publication \"Surface formation, preservation, and history of low-porosity crusts at the WAIS Divide site, West Antarctica\" DOI: https://doi.org/10.5194/tc-12-1-2018", "east": -112.085, "geometry": ["POINT(-112.085 -79.467)"], "keywords": "Antarctica; Atmosphere; AWS; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Meteorology; Physical Properties; Snow Pit; Temperature; WAIS Divide; WAIS Divide Ice Core; Weatherstation", "locations": "Antarctica; WAIS Divide", "north": -79.467, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "persons": "Fegyveresi, John; Alley, Richard", "project_titles": "Collaborative Research: Continued Study of Physical Properties of the WAIS Divide Deep Core; Collaborative Research: Physical Properties of the WAIS Divide Deep Core", "projects": [{"proj_uid": "p0000038", "repository": "USAP-DC", "title": "Collaborative Research: Physical Properties of the WAIS Divide Deep Core"}, {"proj_uid": "p0000027", "repository": "USAP-DC", "title": "Collaborative Research: Continued Study of Physical Properties of the WAIS Divide Deep Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.467, "title": "WAIS Divide Surface and Snow-pit Data, 2009-2013", "uid": "601079", "west": -112.085}, {"awards": "1043740 Lenczewski, Melissa", "bounds_geometry": ["POLYGON((165 -77.5,165.3 -77.5,165.6 -77.5,165.9 -77.5,166.2 -77.5,166.5 -77.5,166.8 -77.5,167.1 -77.5,167.4 -77.5,167.7 -77.5,168 -77.5,168 -77.6,168 -77.7,168 -77.8,168 -77.9,168 -78,168 -78.1,168 -78.2,168 -78.3,168 -78.4,168 -78.5,167.7 -78.5,167.4 -78.5,167.1 -78.5,166.8 -78.5,166.5 -78.5,166.2 -78.5,165.9 -78.5,165.6 -78.5,165.3 -78.5,165 -78.5,165 -78.4,165 -78.3,165 -78.2,165 -78.1,165 -78,165 -77.9,165 -77.8,165 -77.7,165 -77.6,165 -77.5))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "The PI proposes to utilize computer models used by hydrogeologists to establish the fate and transport of contamination and determine the extent of drilling fluid contamination in the ANDRILL SMS core. For these models, previously collected logs of lithology, porosity, fracture density, fracture type, fracture orientation, drilling fluid loss, drilling fluid characteristics and temperature will be used as input parameters. In addition, biodegradation and sorption constants for the drilling fluid will be determined and incorporated into the models. Samples of drilling fluids used during coring as well as the return fluids were collected at the drill site using standard microbiological sampling techniques. Fluids will be tested at in situ temperatures under aerobic and anaerobic conditions to determine biodegradation constants. Sorption will be determined between the drilling fluids and core samples using standard isotherm methods. Geochemical and microbial fingerprints of the fluids and the changes during biodegradation will determine the potential impact of the drilling fluids on the isolated microbial communities and the geochemistry within various subsurface lithologic units beneath the southern McMurdo Sound in Antarctica. The results of this study could potentially provide guidelines on developing less detrimental methods for future exploration, if deemed necessary through this research.\nThis proposed project will train a graduate student. The methods developed for analyses of samples in this project will serve as a guide for future studies of similar interest and will improve the understanding of ecological impacts of geologic drilling in Antarctica. The results of this study will be used as a reference for comparison with future studies examining newly developed, and improved, sample collection methods in future exploratory drilling projects in pristine environments. The PI is new to Antarctic research.\n", "east": 168.0, "geometry": ["POINT(166.5 -78)"], "keywords": "Andrill; Antarctica; Chemistry:fluid; Chemistry:Fluid; Chemistry:rock; Chemistry:Rock; Drilling Fluid; Geochemistry; McMurdo; Ross Sea; Sediment Core", "locations": "Ross Sea; McMurdo; Antarctica", "north": -77.5, "nsf_funding_programs": null, "persons": "Lenczewski, Melissa", "project_titles": "Fate of Drilling Fluids during the South McMurdo Sound Project (SMS) of the Antarctic Geological Drilling Program (ANDRILL)", "projects": [{"proj_uid": "p0000468", "repository": "USAP-DC", "title": "Fate of Drilling Fluids during the South McMurdo Sound Project (SMS) of the Antarctic Geological Drilling Program (ANDRILL)"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "ANDRILL", "south": -78.5, "title": "Fate of Drilling Fluids during the South McMurdo Sound Project (SMS) of the Antarctic Geological Drilling Program (ANDRILL)", "uid": "600129", "west": 165.0}]

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