USAP-DC

{"dp_type": "Project", "free_text": "Microstructure"}

[{"awards": "1141411 Baker, Ian", "bounds_geometry": "POLYGON((-180 -60,-144 -60,-108 -60,-72 -60,-36 -60,0 -60,36 -60,72 -60,108 -60,144 -60,180 -60,180 -63,180 -66,180 -69,180 -72,180 -75,180 -78,180 -81,180 -84,180 -87,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -87,-180 -84,-180 -81,-180 -78,-180 -75,-180 -72,-180 -69,-180 -66,-180 -63,-180 -60))", "dataset_titles": "Laboratory Experiments with H2SO4-Doped Ice; The Effects of Soluble Impurities on the Flow and Fabric of Polycrystalline Ice", "datasets": [{"dataset_uid": "601081", "doi": "10.15784/601081", "keywords": null, "people": "Hammonds, Kevin", "repository": "USAP-DC", "science_program": null, "title": "Laboratory Experiments with H2SO4-Doped Ice", "url": "https://www.usap-dc.org/view/dataset/601081"}, {"dataset_uid": "600380", "doi": "10.15784/600380", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Physical Properties; Snow", "people": "Baker, Ian", "repository": "USAP-DC", "science_program": null, "title": "The Effects of Soluble Impurities on the Flow and Fabric of Polycrystalline Ice", "url": "https://www.usap-dc.org/view/dataset/600380"}], "date_created": "Fri, 09 Oct 2020 00:00:00 GMT", "description": "Baker/1141411 This award supports a project to undertake a systematic examination of the effects of soluble impurities, particularly sulfuric acid, on the creep of polycrystalline ice as function of temperature, strain rate and impurity concentration. The working hypothesis is that soluble impurities will increase the flow rate of polycrystalline ice compared to high-purity ice, that this effect will be temperature dependent and that the impurities by affecting the re-crystallization and grain growth will change the fabric of the ice. Both H2SO4-doped and high-purity poly-crystalline ice will be produced by freezing sheets of ice, breaking them up, sieving the ice particles and then sintering them in a mold into fine-grained cylindrical specimens with at least ten grains across their diameter. The resulting microstructures (dislocation structure, grain size and shape, grain boundary character and micro-structural location of the acid) will be characterized using a variety of techniques including: optical microscopy, scanning electron microscopy, including secondary electron imaging, electron backscattered patterns, energy dispersive X-ray spectroscopy, electron channeling contrast imaging, and X-ray topography. The creep of both the H2SO4-doped and the high-purity polycrystalline ice will be undertaken at a range of temperatures and stresses. The ice?s response to the creep deformation (grain boundary sliding, dislocation motion, re-crystallization, grain boundary migration, impurity redistribution) will be studied using a combination of methods. The creep behavior will be modeled and related to the microstructure. Of particular interest is how impurities affect the activation energy for creep. The intellectual merit of the work is that it will lead to a better understanding of glacier ice and will enable glaciologists to model the influence of impurities on the flow and fabric development in polycrystalline ice. The broader impacts of the project include the knowledge that will be gained of the effects of impurities on the flow of ice which will allow paleoclimatologists to better interpret ice core data and will allow scientists developing predictive models to better address the flow of ice sheets under various climate change scenarios. The project will also lead to the education and training of a Ph.D. student, several undergraduates and some high school students. Results from the research will be published in refereed journals. Several undergraduates, typically two per year, will also perform the work. Dartmouth aggressively courts minority students at all degree levels, and we will seek women or minority group undergraduates for this project. The undergraduates will be supported by Dartmouth?s nationally-honored Women In Science Project or by REU funding. The undergraduates? research will integrate closely with the Ph.D. student?s studies. Hanover High School students will also be involved in the project and develop an educational kit to introduce students to the properties of ice. Results from the research will be published in refereed journals and presented at conferences.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "USA/NSF; USAP-DC; SNOW/ICE; Amd/Us; LABORATORY; Antarctica; AMD", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Baker, Ian", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "The Effects of Soluble Impurities on the Flow and Fabric of Polycrystalline Ice", "uid": "p0010133", "west": -180.0}, {"awards": "1142035 Obbard, Rachel; 1142167 Pettit, Erin", "bounds_geometry": "POLYGON((-112.3 -79.2,-112.2 -79.2,-112.1 -79.2,-112 -79.2,-111.9 -79.2,-111.8 -79.2,-111.7 -79.2,-111.6 -79.2,-111.5 -79.2,-111.4 -79.2,-111.3 -79.2,-111.3 -79.23,-111.3 -79.26,-111.3 -79.29,-111.3 -79.32,-111.3 -79.35,-111.3 -79.38,-111.3 -79.41,-111.3 -79.44,-111.3 -79.47,-111.3 -79.5,-111.4 -79.5,-111.5 -79.5,-111.6 -79.5,-111.7 -79.5,-111.8 -79.5,-111.9 -79.5,-112 -79.5,-112.1 -79.5,-112.2 -79.5,-112.3 -79.5,-112.3 -79.47,-112.3 -79.44,-112.3 -79.41,-112.3 -79.38,-112.3 -79.35,-112.3 -79.32,-112.3 -79.29,-112.3 -79.26,-112.3 -79.23,-112.3 -79.2))", "dataset_titles": "ApRES Firn Density Study; ApRES Vertical Strain Study; GPS Horizontal Strain Network; South Pole (SPICEcore) Borehole Deformation; WAIS Divide Borehole Deformation", "datasets": [{"dataset_uid": "601314", "doi": "10.15784/601314", "keywords": "Acoustic Televiewer; Anisotropy; Antarctica; Borehole Logging; Deformation; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Flow; WAIS Divide; WAIS Divide Ice Core", "people": "Pettit, Erin", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "WAIS Divide Borehole Deformation", "url": "https://www.usap-dc.org/view/dataset/601314"}, {"dataset_uid": "601322", "doi": "10.15784/601322", "keywords": "Antarctica; Firn; Firn Density; Glaciology; Ice Penetrating Radar; Phase Sensitive Radar; Radar; Snow/ice; Snow/Ice; WAIS Divide", "people": "Pettit, Erin", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "ApRES Firn Density Study", "url": "https://www.usap-dc.org/view/dataset/601322"}, {"dataset_uid": "601323", "doi": "10.15784/601323", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Penetrating Radar; Ice Strain; Phase Sensitive Radar; Radar; Snow/ice; Snow/Ice; WAIS Divide", "people": "Pettit, Erin", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "ApRES Vertical Strain Study", "url": "https://www.usap-dc.org/view/dataset/601323"}, {"dataset_uid": "200141", "doi": "", "keywords": null, "people": null, "repository": "UNAVCO", "science_program": null, "title": "GPS Horizontal Strain Network", "url": ""}, {"dataset_uid": "601315", "doi": "10.15784/601315", "keywords": "Acoustic Televiewer; Anisotropy; Antarctica; Borehole Logging; Deformation; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Ice Flow; Snow/ice; Snow/Ice; South Pole; SPICEcore", "people": "Pettit, Erin", "repository": "USAP-DC", "science_program": "SPICEcore", "title": "South Pole (SPICEcore) Borehole Deformation", "url": "https://www.usap-dc.org/view/dataset/601315"}], "date_created": "Fri, 15 May 2020 00:00:00 GMT", "description": "1142167/Pettit This award supports a project to develop a better understanding of the relation between ice microstructure, impurities, and ice flow and their connection to climate history for the West Antarctic Ice Sheet (WAIS) ice core site. This work builds on several ongoing studies at Siple Dome in West Antarctica and Dome C in East Antarctica. It is well known that the microstructure of ice evolves with depth and time in an ice sheet. This evolution of microstructure depends on the ice flow field, temperature, and impurity content. The ice flow field, in turn, depends on microstructure, leading to feedbacks that create layered variation in microstructure that relates to climate and flow history. The research proposed here focuses on developing a better understanding of: 1) how ice microstructure evolves with time and stress in an ice sheet and how that relates to impurity content, temperature, and strain rate; 2) how variations in ice microstructure and impurity content affect ice flow patterns near ice divides (on both small (1cm to 1m) and large (1m to 100km) scales); and 3) in what ways is the spatial variability of ice microstructure and its effect on ice flow important for interpretation of climate history in the WAIS Divide ice core. The study will integrate existing ice core and borehole data with a detailed study of ice microstructure using Electron Backscatter Diffraction (EBSD) techniques and measurements of borehole deformation through time using Acoustic Televiewers. This will be the first study to combine these two novel techniques for studying the relation between microstructure and deformation and it will build on other data being collected as part of other WAIS Divide borehole logging projects (e.g. sonic velocity, optical dust logging, temperature and other measurements on the ice core including fabric measurements from thin section analyses as well as studies of ice chemistry and stable isotopes. The intellectual merit of the work is that it will improve interpretation of ice core data (especially information on past accumulation) and overall understanding of ice flow. The broader impacts are that the work will ultimately contribute to a better interpretation of ice core records for both paleoclimate studies and for ice flow history, both of which connect to the broader questions of the role of ice in the climate system. The work will also advance the careers of two early-career female scientists, including one with a hearing impairment disability. This project will support a PhD student at the UAF and provide research and field experience for two or three undergraduates at Dartmouth. The PIs plan to include a teacher on their field team and collaborate with UAF\u0027s \"From STEM to STEAM\" toward enhancing the connection between art and science.", "east": -111.3, "geometry": "POINT(-111.8 -79.35)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR", "is_usap_dc": true, "keywords": "FIELD INVESTIGATION; GLACIERS/ICE SHEETS; WAIS Divide; ICE CORE RECORDS; USAP-DC; GLACIER MOTION/ICE SHEET MOTION; Radar", "locations": "WAIS Divide", "north": -79.2, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": null, "persons": "Pettit, Erin; Obbard, Rachel", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "UNAVCO; USAP-DC", "science_programs": "WAIS Divide Ice Core; SPICEcore", "south": -79.5, "title": "Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica", "uid": "p0010098", "west": -112.3}, {"awards": "1246045 Waddington, Edwin", "bounds_geometry": "POLYGON((-180 -70,-144 -70,-108 -70,-72 -70,-36 -70,0 -70,36 -70,72 -70,108 -70,144 -70,180 -70,180 -72,180 -74,180 -76,180 -78,180 -80,180 -82,180 -84,180 -86,180 -88,180 -90,144 -90,108 -90,72 -90,36 -90,0 -90,-36 -90,-72 -90,-108 -90,-144 -90,-180 -90,-180 -88,-180 -86,-180 -84,-180 -82,-180 -80,-180 -78,-180 -76,-180 -74,-180 -72,-180 -70))", "dataset_titles": "Code for inference of fabric from sonic velocity and thin-section measurements.; Code for models involving stochastic treatment of ice fabric", "datasets": [{"dataset_uid": "000244", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for models involving stochastic treatment of ice fabric", "url": "https://github.com/mjhay/stochastic_fabric"}, {"dataset_uid": "000243", "doi": "", "keywords": null, "people": null, "repository": "GitHub", "science_program": null, "title": "Code for inference of fabric from sonic velocity and thin-section measurements.", "url": "https://github.com/mjhay/neem_sonic_model"}], "date_created": "Mon, 02 Apr 2018 00:00:00 GMT", "description": "Waddington/1246045 This award supports a project to investigate the onset and growth of folds and other disturbances seen in the stratigraphic layers of polar ice sheets. The intellectual merit of the work is that it will lead to a better understanding of the grain-scale processes that control the development of these stratigraphic features in the ice and will help answer questions such as what processes can initiate such disturbances. Snow is deposited on polar ice sheets in layers that are generally flat, with thicknesses that vary slowly along the layers. However, ice cores and ice-penetrating radar show that in some cases, after conversion to ice, and following lengthy burial, the layers can become folded, develop pinch-and-swell structures (boudinage), and be sheared by ice flow, at scales ranging from centimeters to hundreds of meters. The processes causing these disturbances are still poorly understood. Disturbances appear to develop first at the ice-crystal scale, then cascade up to larger scales with continuing ice flow and strain. Crystal-scale processes causing distortions of cm-scale layers will be modeled using Elle, a microstructure-modeling package, and constrained by fabric thin-sections and grain-elongation measurements from the West Antarctic Ice Sheet divide ice-core. A full-stress continuum anisotropic ice-flow model coupled to an ice-fabric evolution model will be used to study bulk flow of anisotropic ice, to understand evolution and growth of flow disturbances on the meter and larger scale. Results from this study will assist in future ice-core site selection, and interpretation of stratigraphy in ice cores and radar, and will provide improved descriptions of rheology and stratigraphy for ice-sheet flow models.The broader impacts are that it will bring greater understanding to ice dynamics responsible for stratigraphic disturbance. This information is valuable to constrain depth-age relationships in ice cores for paleoclimate study. This will allow researchers to put current climate change in a more accurate context. This project will provide three years of support for a graduate student as well as support and research experience for an undergraduate research assistant; this will contribute to development of talent needed to address important future questions in glaciology and climate change. The research will be communicated to the public through outreach events and results from the study will be disseminated through public and professional meetings as well as journal publications. The project does not require field work in Antarctica.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "NOT APPLICABLE; USAP-DC", "locations": null, "north": -70.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Waddington, Edwin D.", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repo": "GitHub", "repositories": "GitHub", "science_programs": null, "south": -90.0, "title": "Anisotropic Ice and Stratigraphic Disturbances", "uid": "p0000073", "west": -180.0}, {"awards": "1246320 Kruckenberg, Seth", "bounds_geometry": "POINT(-144.75 -76.53)", "dataset_titles": null, "datasets": null, "date_created": "Mon, 19 Sep 2016 00:00:00 GMT", "description": "Intellectual Merit: The PI proposes an investigation of mantle xenoliths entrained within a suite of ~1.4 Ma mafic volcanic centers in the Fosdick Mountains, Antarctica. These recently entrained mantle xenoliths offer a unique opportunity to characterize the West Antarctic lithospheric mantle that has been subject to active modification from Cretaceous to Present by plate-boundary processes, such as orthogonal to oblique plate convergence, intracontinental rifting, continental breakup, and Neogene volcanism. These volcanic centers derive from heterogeneous mantle sources and host a compositionally diverse suite of mantle xenoliths that have varied mineral assemblages and microstructures. The proposed research has two complementary goals: to assess structural and compositional heterogeneity within the upper mantle and the variability of intrinsic and extrinsic variables at a variety of lithospheric levels; and to use textural and compositional characterization of the xenolith suite to elucidate possible causes of heterogeneous seismic anisotropy within the Marie Byrd Land mantle lithosphere and inform competing hypotheses explaining the active volcanism, thermal anomaly, and slow seismic velocities beneath West Antarctica. Furthermore, characterization of samples of the mantle beneath West Antarctica provides a type of \u0027ground truth\u0027 in support of contemporary ANET/POLENET seismology research that seeks to determine mantle composition, temperature, and sources of seismic anisotropy. Broader impacts: The PI is in his first-year as a tenure track faculty member at Boston College. A postdoctoral researcher will be trained in EBSD techniques, interdisciplinary polar research, and the mentoring of undergraduate investigators. Two Boston College undergraduates will participate in the research and a priority will be placed on selecting underrepresented minorities and first-generation college students. An existing sample suite assembled over more than 20 years of NSF sponsored field work, will be used. The PI will create a digital database for microstructural, textural, and xenolith data for rapid dissemination to the international Antarctic community.", "east": -144.75, "geometry": "POINT(-144.75 -76.53)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -76.53, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Kruckenberg, Seth", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -76.53, "title": "Integrated Evaluation of Mantle Xenoliths from the Fosdick Mountains, Antarctica", "uid": "p0000400", "west": -144.75}, {"awards": "0944615 Brown, Michael; 0944600 Siddoway, Christine", "bounds_geometry": "POLYGON((-146.5 -76,-145.95 -76,-145.4 -76,-144.85 -76,-144.3 -76,-143.75 -76,-143.2 -76,-142.65 -76,-142.1 -76,-141.55 -76,-141 -76,-141 -76.15,-141 -76.3,-141 -76.45,-141 -76.6,-141 -76.75,-141 -76.9,-141 -77.05,-141 -77.2,-141 -77.35,-141 -77.5,-141.55 -77.5,-142.1 -77.5,-142.65 -77.5,-143.2 -77.5,-143.75 -77.5,-144.3 -77.5,-144.85 -77.5,-145.4 -77.5,-145.95 -77.5,-146.5 -77.5,-146.5 -77.35,-146.5 -77.2,-146.5 -77.05,-146.5 -76.9,-146.5 -76.75,-146.5 -76.6,-146.5 -76.45,-146.5 -76.3,-146.5 -76.15,-146.5 -76))", "dataset_titles": "Rock Samples collected from bedrock exposures, Ford Ranges, MBL", "datasets": [{"dataset_uid": "200415", "doi": "", "keywords": null, "people": null, "repository": "Polar Rock Repository", "science_program": null, "title": "Rock Samples collected from bedrock exposures, Ford Ranges, MBL", "url": "http://bprc.osu.edu/rr/"}], "date_created": "Thu, 09 Oct 2014 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eThe northern Ford ranges in Marie Byrd Land, Antarctica, record events and processes that transformed a voluminous succession of Lower Paleozoic turbidites intruded by calc-alkaline plutonic rocks into differentiated continental crust along the margin of Gondwana. In this study the Fosdick migmatite?granite complex will be used to investigate crustal evolution through an integrated program of fieldwork, structural geology, petrology, mineral equilibria modeling, geochronology and geochemistry. The PIs propose detailed traverses at four sites within the complex to investigate Paleozoic and Mesozoic orogenic cycles. They will use petrological associations, structural geometry, and microstructures of host gneisses and leucogranites to distinguish the migration and coalescence patterns for remnant melt flow networks, and carry out detailed sampling for geochronology, geochemistry and isotope research. Mafic plutonic phases will be sampled to acquire information about mantle contributions at the source. Mineral equilibria modeling of source rocks and granite products, combined with in situ mineral dating, will be employed to resolve the P?T?t trajectories arising from thickening/thinning of crust during orogenic cycles and to investigate melting and melt loss history. \u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis work involves research and educational initiatives for an early career female scientist, as well as Ph.D. and undergraduate students. Educational programs for high school audiences and undergraduate courses on interdisciplinary Antarctic science will be developed.", "east": -141.0, "geometry": "POINT(-143.75 -76.75)", "instruments": null, "is_usap_dc": true, "keywords": "Tectonic; TECTONICS; Transcurrent Faults; MAJOR ELEMENTS; Migmatite; Structural Geology; Gneiss Dome; Geochronology; AGE DETERMINATIONS; Detachment Faults; Marie Byrd Land", "locations": "Marie Byrd Land", "north": -76.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Siddoway, Christine; Brown, Mike", "platforms": null, "repo": "Polar Rock Repository", "repositories": "Polar Rock Repository", "science_programs": null, "south": -77.5, "title": "Collaborative research: Polyphase Orogenesis and Crustal Differentiation in West Antarctica", "uid": "p0000259", "west": -146.5}, {"awards": "0944078 Albert, Mary", "bounds_geometry": "POINT(112.05 79.28)", "dataset_titles": "Firn Permeability and Density at WAIS Divide", "datasets": [{"dataset_uid": "609602", "doi": "10.7265/N57942NT", "keywords": "Antarctica; Firn; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Physical Properties; WAIS Divide; WAIS Divide Ice Core", "people": "Albert, Mary R.", "repository": "USAP-DC", "science_program": "WAIS Divide Ice Core", "title": "Firn Permeability and Density at WAIS Divide", "url": "https://www.usap-dc.org/view/dataset/609602"}], "date_created": "Fri, 15 Aug 2014 00:00:00 GMT", "description": "This award supports a project to investigate the transformations from snow to firn to ice and the underlying physics controlling firn\u0027s ability to store atmospheric samples from the past. Senior researchers, a graduate student, and several undergraduates will make high-resolution measurements of both the diffusivity and permeability profiles of firn cores from several sites in Antarctica and correlate the results with their microstructures quantified using advanced materials characterization techniques (scanning electron microscopy and x-ray computed tomography). The use of cores from different sites will enable us to examine the influence of different local climate conditions on the firn structure. We will use the results to help interpret existing measurements of firn air chemical composition at several sites where firn air measurements exist. There are three closely-linked goals of this project: to quantify the dependence of interstitial transport properties on firn microstructure from the surface down to the pore close-off depth, to determine at what depths bubbles form and entrap air, and investigate the extent to which these features exhibit site-to-site differences, and to use the measurements of firn air composition and firn structure to better quantify the differences between atmospheric composition (present and past), and the air trapped in both the firn and in air bubbles within ice by comparing the results of the proposed work with firn air measurements that have been made at the WAIS Divide and Megadunes sites. The broader impacts of this project are that the study will this study will enable us to elucidate the fundamental controls on the metamorphism of firn microstructure and its impact on processes of gas entrapment that are important to understanding ice core evidence of past atmospheric composition and climate change. The project will form the basis for the graduate research of a PhD student at Dartmouth, with numerous opportunities for undergraduate involvement in cold room measurements and outreach. The investigators have a track record of successfully mentoring women students, and will build on this experience. In conjunction with local earth science teachers, and graduate and undergraduate students will design a teacher-training module on the role of the Polar Regions in climate change. Once developed and tested, this module will be made available to the broader polar research community for their use with teachers in their communities.", "east": -112.05, "geometry": "POINT(-112.05 -79.28)", "instruments": "EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e MICROTOMOGRAPHY; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e MICROSCOPES; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e SCANNING ELECTRON MICROSCOPES", "is_usap_dc": true, "keywords": "Firn Air; FIELD SURVEYS; Physics; GROUND-BASED OBSERVATIONS; Antarctica; Megadunes; Tomography; Wais Divide-project; Firn Core; FIELD INVESTIGATION; Not provided; Firn Permeability; LABORATORY; Visual Observations; Ice; Firn; WAIS Divide; Microstructure; Density", "locations": "Antarctica; WAIS Divide", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Baker, Ian; Albert, Mary R.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.28, "title": "Firn Metamorphism: Microstructure and Physical Properties", "uid": "p0000049", "west": -112.05}, {"awards": "0738975 Baker, Ian", "bounds_geometry": null, "dataset_titles": "Siple Dome A (SDMA) Grain Orientation 640 - 790 Meters", "datasets": [{"dataset_uid": "609526", "doi": "10.7265/N53T9F5X", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Sample/collection Description; Sample/Collection Description; Siple Dome; Siple Dome Ice Core; South Pole; WAISCORES", "people": "Obbard, Rachel; Sieg, Katherine; Baker, Ian", "repository": "USAP-DC", "science_program": "Siple Dome Ice Core", "title": "Siple Dome A (SDMA) Grain Orientation 640 - 790 Meters", "url": "https://www.usap-dc.org/view/dataset/609526"}], "date_created": "Mon, 26 Nov 2012 00:00:00 GMT", "description": "This award supports a project to fully characterize the microstructure in ice cores, in particular the microstructural locations of impurities, grain orientations and strain gradients. This work will complement the optical observations, electrical conductivity measurement, and precise, detailed measurements of the soluble ion and gas contents that are performed by others. Linking the concentrations of soluble ions and gases, measured to a few parts per billion, to the optically determined annual layer structure and the stable isotope data in ice cores has enabled a great deal to be established about the concentrations and depth/age distributions of particles, trace gases and impurities for several polar ice cores. Ice core studies carried out by several groups contribute immensely to our understanding of paleoclimate and, to our ability to predict future climate change. The work will build on previous measurements and technique development in this area, as well as focusing on new techniques to characterize ice cores. The work will use both scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDS) and confocal scanning optical microscopy coupled with Raman spectroscopy (RS) to determine the microstructural locations of impurities and correlate this information with depth/age, and impurity type and concentration for several polar ice cores. The Broader Impacts of the proposed work are that knowledge of the location of impurities coupled with the grain orientation (both c- and a-axis) and grain misorientation information will allow paleoclimatologists to better interpret ice core data and other scientists to understand and model the physical and mechanical properties of natural ice sheets. Other Broader Impacts of the work are that the work will be performed and lead to the education of a Ph.D. student. At the end of the project, as well as the knowledge gained from coursework, the graduate student will have experience in ice core specimen preparation and characterization using scanning electron microscopy, x-ray microanalysis, confocal scanning microscopy, Raman spectroscopy and ion chromatography. Results from the research will be published in refereed journals, presented at conferences, and placed on a web page.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e SCANNING ELECTRON MICROSCOPES", "is_usap_dc": true, "keywords": "FEI Xl30 Environmental Scanning Electron Microscope - Field Emission Gun (esem - Feg); LABORATORY; Electron Backscatter Diffraction", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Baker, Ian; Obbard, Rachel; Sieg, Katherine", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": null, "title": "Advanced Microstructural Characterization of Polar Ice Cores", "uid": "p0000178", "west": null}, {"awards": "9910093 Powell, Thomas", "bounds_geometry": null, "dataset_titles": "Expedition data of NBP0104", "datasets": [{"dataset_uid": "002657", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0104", "url": "https://www.rvdata.us/search/cruise/NBP0104"}, {"dataset_uid": "002584", "doi": null, "keywords": null, "people": null, "repository": "R2R", "science_program": null, "title": "Expedition data of NBP0104", "url": "https://www.rvdata.us/search/cruise/NBP0104"}], "date_created": "Tue, 04 May 2010 00:00:00 GMT", "description": "This project is a contribution to a coordinated attempt to understand the interactions of biological and physical dynamics by developing relationships among the evolution of the antarctic winter ice and snow cover, biological habitat variability, and the seasonal progression of marine ecological processes. The work will be carried out in the context of the Southern Ocean Experiment of the Global Ocean Ecosystem Dynamics Study (Globec), a large, multi-investigator study of the winter survival strategy of krill under the antarctic sea ice in the vicinity of Marguerite Bay on the western side of the Antarctic Peninsula. The objective of this project is to make a quantitative assessment of the small scale temperature and salinity structure of the oceanic surface layer in order to study the effect of stratification and turbulence on the biochemical and biological processes under the winter sea ice. The water masses on the continental shelf off Marguerite Bay consist of inflowing Upper Circumpolar Deep Water, which is relatively warm, salty, oxygen-poor, and nutrient-rich. In winter atmospheric processes cool and freshen this water, and recharge it with oxygen to produce Antarctic Surface Water which is diffused seaward, and supports both a sea ice cover and a productive krill-based food web. The modification processes work through mixing associated with shear instabilities of the internal wave field, double diffusion of salt and heat, and mixing driven by surface stress and convection. These processes will be quantified with two microstructure profilers, capable of resolving the small but crucial vertical variations that drive these processes. ***", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROFILERS/SOUNDERS \u003e ACOUSTIC SOUNDERS \u003e MSBS", "is_usap_dc": false, "keywords": "R/V NBP", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Powell, Thomas", "platforms": "WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V NBP", "repo": "R2R", "repositories": "R2R", "science_programs": null, "south": null, "title": "Collaborative Research: WinDSSOcK: Winter Distribution and Success of Southern Ocean Krill", "uid": "p0000804", "west": null}, {"awards": "0538639 Waddington, Edwin", "bounds_geometry": "POLYGON((-112.1 -79.4,-112.09 -79.4,-112.08 -79.4,-112.07 -79.4,-112.06 -79.4,-112.05 -79.4,-112.04 -79.4,-112.03 -79.4,-112.02 -79.4,-112.01 -79.4,-112 -79.4,-112 -79.41,-112 -79.42,-112 -79.43,-112 -79.44,-112 -79.45,-112 -79.46,-112 -79.47,-112 -79.48,-112 -79.49,-112 -79.5,-112.01 -79.5,-112.02 -79.5,-112.03 -79.5,-112.04 -79.5,-112.05 -79.5,-112.06 -79.5,-112.07 -79.5,-112.08 -79.5,-112.09 -79.5,-112.1 -79.5,-112.1 -79.49,-112.1 -79.48,-112.1 -79.47,-112.1 -79.46,-112.1 -79.45,-112.1 -79.44,-112.1 -79.43,-112.1 -79.42,-112.1 -79.41,-112.1 -79.4))", "dataset_titles": null, "datasets": null, "date_created": "Thu, 01 Apr 2010 00:00:00 GMT", "description": "0538639\u003cbr/\u003eWaddington\u003cbr/\u003eThis award supports a project to study the patterns of accumulation variation and microstructural properties near the WAIS Divide ice core site in a 2.5 km array of 20 m boreholes. Borehole Optical Stratigraphy (BOS) is a novel optical measurement system that detects annual-scale layers in firn that result from changes in firn microstructure, giving annual-scale records of how accumulation varied spatially over the last 40-50 years. Data from borehole optical stratigraphy can eventually be calibrated against other data on the microstructural parameters of firn to calibrate BOS\u0027s sensitivity to density, pore-volume, and pore-shape variations, and to show by proxy how these parameters vary in space across the survey area. Statistical analysis of layer-thickness and layer-brightness data will enable prediction of: 1) interannual accumulation variability, 2) variability in layer-thickness at decadal scales due to changing spatial patterns in accumulation and 3) variability in microstructure-driven metamorphism due to changing spatial patterns of microstructure. With these statistics in hand, a scientist measuring climatic shifts found in the WAIS Divide ice core will be able to determine the fraction by which signals they measure exceed the signal due to background accumulation variations. As an added benefit, while still in the field, we will determine a preliminary depth-age scale for the firn by optical layer-counting, to the depth of the deepest air-filled firn hole available. This will be a valuable result for core-drilling operations and for preliminary data-analysis on the core. In terms of broader impacts, this project will advance education by training a post-doctoral student in field techniques. The P.I. and the post-doctoral researcher will participate in an undergraduate seminar called \"What is Scientific Research?\", incorporating progress and results from this project. They will also communicate about their progress and field experience with a middle-school science and math class.", "east": -112.0, "geometry": "POINT(-112.05 -79.45)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e OPTICAL DUST LOGGERS", "is_usap_dc": false, "keywords": "Spatial Variability; FIELD INVESTIGATION; Not provided; LABORATORY; Stratigraphy; Borehole Optical Stratigraphy; Optical Layer-Counting; Microstructure; Firn; Depth-Age-Model; Optical; WAIS Divide; FIELD SURVEYS; Accumulation", "locations": "WAIS Divide", "north": -79.4, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fudge, T. J.; Waddington, Edwin D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": -79.5, "title": "Spatial Variability in Firn Properties from Borehole Optical Stratigraphy at the Inland WAIS Core Site", "uid": "p0000237", "west": -112.1}, {"awards": "9980379 Baker, Ian", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Mon, 15 Feb 2010 00:00:00 GMT", "description": "This award is for support for three years of funding to study the effects of impurities on the flow of poly- crystalline ice. It has been known for thirty years that both hydrofluoric acid (HF) and hydrochloric acid (HCl) dramatically decrease the strength of ice and recent work by the author\u0027s group has shown that sulfuric acid (H2SO4) produces a similar reduction in strength. However, these data are for single crystals at strain rates and stresses that far exceed those found in glaciers and ice sheets, and often at concentrations that far exceed those in natural ice. Therefore, it is not known how impurities found in nature affect the flow of polycrystalline ice at slow strain rates. In this research, the effects of nitric acid and sulfuric acid (which are naturally occurring impurities in ice) on the microstructure (dislocation structure, grain boundary structure and location of the acids) and creep of polycrystalline ice (at a range of temperatures and stresses) will be determined. The ice\u0027s response to creep deformation will be studied using a combination of x-ray topography, optical microscopy and scanning electron microscopy. X-ray microanalysis in an environmental scanning electron microscope will be used to study the location of impurities. The structure and creep behavior of the acid-doped ice will be compared with those of both high-purity laboratory-grown ice and ice from Byrd Station, Antarctica. The end-result of this project will be to elucidate the effects of naturally-occurring acid impurities on the mechanical properties of polycrystalline ice under conditions relevant to the deformation of glaciers and ice sheets, including and understanding of how impurities affect the underlying deformation mechanisms.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e ION CHROMATOGRAPHS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e PARTICLE DETECTORS; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e SCANNING ELECTRON MICROSCOPES", "is_usap_dc": true, "keywords": "Ice Core Data; Ice Core; Microstructure; Ice Sheet; Ice Core Chemistry; Antarctic Ice Sheet; LABORATORY", "locations": "Antarctic Ice Sheet", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Baker, Ian; Obbard, Rachel", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": null, "title": "The Effects of Impurities on the Flow of Polycrystalline Ice", "uid": "p0000015", "west": null}, {"awards": "0125570 Scambos, Ted; 0125276 Albert, Mary", "bounds_geometry": null, "dataset_titles": "Access AGDC data online by navigating to Data Sets. Data sets are arranged by Principal Investigators. Access data that are combined into multiple data sets, or compiled products.; AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation; GPR and GPS Data: Characteristics of Snow Megadunes and their Potential Effects on Ice Core Interpretation; Snow and Firn Permeability: Characteristics of Snow Megadunes and their Potential Effects on Ice Core Interpretation; The Antarctic Glaciological Data Center (AGDC) at the National Snow and Ice Data Center (NSIDC) archives and distributes Antarctic glaciological and cryospheric system data collected by the U.S. Antarctic Program.", "datasets": [{"dataset_uid": "609282", "doi": "10.7265/N5Q23X5F", "keywords": "Antarctica; East Antarctic Plateau; Glaciology; GPR; GPS; Navigation; Paleoclimate; Snow/ice; Snow/Ice", "people": "Scambos, Ted; Bauer, Rob", "repository": "USAP-DC", "science_program": null, "title": "GPR and GPS Data: Characteristics of Snow Megadunes and their Potential Effects on Ice Core Interpretation", "url": "https://www.usap-dc.org/view/dataset/609282"}, {"dataset_uid": "609283", "doi": "10.7265/N5K935F3", "keywords": "Antarctica; Atmosphere; East Antarctic Plateau; Glaciers/ice Sheet; Glaciers/Ice Sheet; Meteorology; Snow/ice; Snow/Ice", "people": "Bauer, Rob; Fahnestock, Mark; Scambos, Ted; Haran, Terry", "repository": "USAP-DC", "science_program": null, "title": "AWS Data: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation", "url": "https://www.usap-dc.org/view/dataset/609283"}, {"dataset_uid": "001669", "doi": "", "keywords": null, "people": null, "repository": "NSIDC", "science_program": null, "title": "Access AGDC data online by navigating to Data Sets. Data sets are arranged by Principal Investigators. Access data that are combined into multiple data sets, or compiled products.", "url": "http://nsidc.org/data/agdc_investigators.html"}, {"dataset_uid": "609299", "doi": "10.7265/N5639MPD", "keywords": "Antarctica; East Antarctic Plateau; Glaciology; Physical Properties; Snow/ice; Snow/Ice", "people": "Albert, Mary R.; Courville, Zoe; Cathles, Mac", "repository": "USAP-DC", "science_program": null, "title": "Snow and Firn Permeability: Characteristics of Snow Megadunes and their Potential Effects on Ice Core Interpretation", "url": "https://www.usap-dc.org/view/dataset/609299"}, {"dataset_uid": "001343", "doi": "", "keywords": null, "people": null, "repository": "NSIDC", "science_program": null, "title": "The Antarctic Glaciological Data Center (AGDC) at the National Snow and Ice Data Center (NSIDC) archives and distributes Antarctic glaciological and cryospheric system data collected by the U.S. Antarctic Program.", "url": "https://nsidc.org/data/agdc/"}], "date_created": "Wed, 04 Jan 2006 00:00:00 GMT", "description": "This award supports a program of field surveys of an area within the large, well-developed megadune field southeast of Vostok station. The objectives are to determine the physical characteristics of the firn across the dunes, including typical climate indicators such as stable isotopes and major chemical species, and to install instruments to measure the time variation of near-surface wind and temperature with depth, to test and refine hypotheses for megadune formation. Field study will consist of surface snowpit and shallow core sampling, ground penetrating radar (GPR) profiling, GPS topographic and ice motion surveys, AWS installation, accumulation/ ablation measurements, subsurface temperature, and firn permeability studies. Field work in two successive seasons is proposed. Continent-wide remote sensing studies of the dunes will be continued, using the new group of instruments that are now, or will shortly be available (e.g., MODIS, MISR, GLAS, AMSR). The earlier study of topographic, passive microwave, and SAR characteristics will be extended, with the intent of determining the relationships of dune amplitude and wavelength to climate parameters, and further development of models of dune formation. Diffusion, ventilation, and vapor transport processes within the dune firn will be modeled as well. A robust program of outreach is planned and reporting to inform both the public and scientists of the fundamental in-situ and remote sensing characteristics of these uniquely Antarctic features will be an important part of the work. Because of their extreme nature, their broad extent, and their potential impact on the climate record, it is important to improve our current understanding of these. Megadunes are a manifestation of an extreme terrestrial climate and may provide insight on past terrestrial climate, or to processes active on other planets. Megadunes are likely to represent an end-member in firn diagenesis, and as such, may have much to teach us about the processes involved.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e RECORDERS/LOGGERS \u003e AWS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e ICE AUGERS; IN SITU/LABORATORY INSTRUMENTS \u003e PROBES \u003e SNOWPACK TEMPERATURE PROBE; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS; IN SITU/LABORATORY INSTRUMENTS \u003e PROBES \u003e PERMEAMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PHOTON/OPTICAL DETECTORS \u003e CAMERAS \u003e CAMERAS; IN SITU/LABORATORY INSTRUMENTS \u003e CURRENT/WIND METERS \u003e ANEMOMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e GPS \u003e GPS RECEIVERS; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e RADAR; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e IMAGING RADARS \u003e SAR; EARTH REMOTE SENSING INSTRUMENTS \u003e ACTIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e RADAR SOUNDERS \u003e GPR; IN SITU/LABORATORY INSTRUMENTS \u003e CHEMICAL METERS/ANALYZERS \u003e AIR PERMEAMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e CURRENT/WIND METERS \u003e ANEMOMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e POSITIONING/NAVIGATION \u003e RADIO \u003e ARGOS; IN SITU/LABORATORY INSTRUMENTS \u003e PRESSURE/HEIGHT METERS \u003e PRESSURE SENSORS; IN SITU/LABORATORY INSTRUMENTS \u003e TEMPERATURE/HUMIDITY SENSORS \u003e THERMOMETERS \u003e THERMOMETERS; EARTH REMOTE SENSING INSTRUMENTS \u003e PASSIVE REMOTE SENSING \u003e PROFILERS/SOUNDERS \u003e WIND PROFILERS; IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e CORING DEVICES; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e DENSIOMETERS; IN SITU/LABORATORY INSTRUMENTS \u003e GAUGES \u003e BALANCE", "is_usap_dc": true, "keywords": "Internal Layering; ICESAT; Vapor-Redeposition; Antarctic; Wind Speed; FIELD INVESTIGATION; Surface Morphology; Antarctica; GROUND-BASED OBSERVATIONS; ARWS; Polar Firn Air; Microstructure; Gas Diffusivity; WEATHER STATIONS; Surface Temperatures; RADARSAT-2; Ice Core; Wind Direction; AWS; Ice Sheet; Snow Pit; Dunefields; Climate Record; Megadunes; GROUND STATIONS; METEOROLOGICAL STATIONS; Antarctic Ice Sheet; Density; Atmospheric Pressure; Firn Permeability; FIELD SURVEYS; Radar; Permeability; Field Survey; Firn Temperature Measurements; Snow Megadunes; Thermal Conductivity; LANDSAT; Firn; Ice Core Interpretation; East Antarctic Plateau; Not provided; Surface Winds; Sublimation; Snow Density; Ice Climate Record; Glaciology; Snow Permeability; Air Temperature; Paleoenvironment; Automated Weather Station", "locations": "Antarctica; Antarctic Ice Sheet; Antarctic; East Antarctic Plateau", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY \u003e HOLOCENE", "persons": "Courville, Zoe; Cathles, Mac; Scambos, Ted; Bauer, Rob; Fahnestock, Mark; Haran, Terry; Shuman, Christopher A.; Albert, Mary R.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e ARWS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND-BASED OBSERVATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e GROUND STATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e METEOROLOGICAL STATIONS; LAND-BASED PLATFORMS \u003e PERMANENT LAND SITES \u003e WEATHER STATIONS; Not provided; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e ICE, CLOUD AND LAND ELEVATION SATELLITE (ICESAT) \u003e ICESAT; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e LANDSAT \u003e LANDSAT; SPACE-BASED PLATFORMS \u003e EARTH OBSERVATION SATELLITES \u003e RADARSAT \u003e RADARSAT-2", "repo": "USAP-DC", "repositories": "NSIDC; USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: Characteristics of Snow Megadunes and Their Potential Effect on Ice Core Interpretation", "uid": "p0000587", "west": null}]

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