{"dp_type": "Dataset", "free_text": "Deformation"}
[{"awards": "1245871 McCarthy, Christine", "bounds_geometry": null, "date_created": "Thu, 23 Dec 2021 00:00:00 GMT", "description": "This data set contains text files for the experimental logs of ice-on-rock friction experiments that were conducted in a double direct shear apparatus at temperatures of -16.4 C to -2 C. There are eleven files (C28-C34, C39-C41, and C44). Each file contains 4 columns of data that correspond to time (s), vertical displacement (microns), friction, and velocity. The data were prepared by converting voltages from experimental feedbacks, to appropriate units using calibrations, as conducted separate. Miscellaneous loading and unloading data were removed and the data was filtered modestly (100 point moving average filter in matlab). The data set includes all information needed to plot friction or velocity vs. time or displacement from the beginning to end of the run. ", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "McCarthy, Christine M.; Skarbek, Rob; Savage, Heather", "project_titles": "Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers", "projects": [{"proj_uid": "p0010186", "repository": "USAP-DC", "title": "Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Dataset for Tidal modulation of ice streams: Effect of periodic sliding velocity on ice friction and healing", "uid": "601497", "west": null}, {"awards": "1245871 McCarthy, Christine", "bounds_geometry": null, "date_created": "Fri, 30 Jul 2021 00:00:00 GMT", "description": "This data set contains rate and state frictional parameters for ice-on-rock friction experiments that were conducted in a double direct shear apparatus as temperatures of -16.4 C to -2 C. The frictional parameters were deteremined by directly fitting the frictional response to controlled, harmonic oscillations in load point velocity. The data set includes all information needed to reproduce the fits, as well as tables of the frictional parameters for both the aging and slip law forms of frictional state evolution.", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Skarbek, Rob; McCarthy, Christine M.; Savage, Heather", "project_titles": "Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers", "projects": [{"proj_uid": "p0010186", "repository": "USAP-DC", "title": "Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Rate-state friction parameters for ice-on-rock oscillation experiments", "uid": "601467", "west": null}, {"awards": "0440670 Hulbe, Christina", "bounds_geometry": ["POLYGON((-180 -77,-177 -77,-174 -77,-171 -77,-168 -77,-165 -77,-162 -77,-159 -77,-156 -77,-153 -77,-150 -77,-150 -77.9,-150 -78.8,-150 -79.7,-150 -80.6,-150 -81.5,-150 -82.4,-150 -83.3,-150 -84.2,-150 -85.1,-150 -86,-153 -86,-156 -86,-159 -86,-162 -86,-165 -86,-168 -86,-171 -86,-174 -86,-177 -86,180 -86,177.5 -86,175 -86,172.5 -86,170 -86,167.5 -86,165 -86,162.5 -86,160 -86,157.5 -86,155 -86,155 -85.1,155 -84.2,155 -83.3,155 -82.4,155 -81.5,155 -80.6,155 -79.7,155 -78.8,155 -77.9,155 -77,157.5 -77,160 -77,162.5 -77,165 -77,167.5 -77,170 -77,172.5 -77,175 -77,177.5 -77,-180 -77))"], "date_created": "Fri, 19 Feb 2021 00:00:00 GMT", "description": "The surface of the Ross Ice Shelf (RIS) is textured by flow stripes, crevasses and other fea- tures related to ice flow and deformation. Here, moderate resolution optical satellite images are used to map and classify regions of the RIS characterized by different surface textures. Because the textures arise from ice deformation, the map is used to identify structural provinces with common deformation history. We classify four province types: regions associated with large outlet glaciers, shear zones, exten- sion downstream of obstacles and suture zones between provinces with different upstream sources. Adjacent provinces with contrasting histories are in some locations deforming at different rates, suggest- ing that our province map is also an ice fabric map. Structural provinces have more complicated shapes in the part of the ice shelf fed by West Antarctic ice streams than in the part fed by outlet glaciers from the Transantarctic Mountains. The map may be used to infer past variations in stress conditions and flow events that cannot be inferred from flow traces alone.", "east": 155.0, "geometry": ["POINT(-177.5 -81.5)"], "keywords": "Antarctica; Cryosphere", "locations": "Antarctica", "north": -77.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hulbe, Christina; Ledoux, Christine; Forbes, Martin", "project_titles": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams", "projects": [{"proj_uid": "p0000096", "repository": "USAP-DC", "title": "Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -86.0, "title": "MOA-derived Structural Feature Map of the Ross Ice Shelf", "uid": "601432", "west": -150.0}, {"awards": "1142167 Pettit, Erin", "bounds_geometry": ["POINT(-180 -90)"], "date_created": "Mon, 04 May 2020 00:00:00 GMT", "description": "Acoustic Televiewer measures borehole shape and tilt. These data were collected to study detailed borehole deformation with respect to ice properties to expand our understanding of the flow law for ice. ", "east": -180.0, "geometry": ["POINT(-180 -90)"], "keywords": "Acoustic Televiewer; Anisotropy; Antarctica; Borehole Logging; Cryosphere; Deformation; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Ice Flow; Snow/Ice; South Pole; SPICEcore", "locations": "South Pole; Antarctica", "north": -90.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Pettit, Erin", "project_titles": "Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica", "projects": [{"proj_uid": "p0010098", "repository": "USAP-DC", "title": "Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "SPICEcore", "south": -90.0, "title": "South Pole (SPICEcore) Borehole Deformation", "uid": "601315", "west": -180.0}, {"awards": "0732804 McPhee, Miles", "bounds_geometry": ["POINT(166.25 -77.42)"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "The Office of Polar Programs, Antarctic Integrated and System Science Program has made this award to support an interdisciplinary study of the effects of the ocean on the stability of glacial ice in the most dynamic region the West Antarctic Ice Sheet, namely the Pine Island Glacier in the Amundsen Sea Embayment. The collaborative project builds on the knowledge gained by the highly successful West Antarctic Ice Sheet program and is being jointly sponsored with NASA. Recent observations indicate a significant ice loss, equivalent to 10% of the ongoing increase in sea-level rise, in this region. These changes are largest along the coast and propagate rapidly inland, indicating the critical impact of the ocean on ice sheet stability in the region. While a broad range of remote sensing and ground-based instrumentation is available to characterize changes of the ice surface and internal structure (deformation, ice motion, melt) and the shape of the underlying sediment and rock bed, instrumentation has yet to be successfully deployed for observing boundary layer processes of the ocean cavity which underlies the floating ice shelf and where rapid melting is apparently occurring. Innovative, mini ocean sensors that can be lowered through boreholes in the ice shelf (about 500 m thick) will be developed and deployed to automatically provide ocean profiling information over at least three years. Their data will be transmitted through a conducting cable frozen in the borehole to the surface where it will be further transmitted via satellite to a laboratory in the US. Geophysical and remote sensing methods (seismic, GPS, altimetry, stereo imaging, radar profiling) will be applied to map the geometry of the ice shelf, the shape of the sub ice-shelf cavity, the ice surface geometry and deformations within the glacial ice. To integrate the seismic, glaciological and oceanographic observations, a new 3-dimensional coupled ice-ocean model is being developed which will be the first of its kind. NASA is supporting satellite based research and the deployment of a robotic-camera system to explore the environment in the ocean cavity underlying the ice shelf and NSF is supporting all other aspects of this study. \n\nBroader impacts: This project is motivated by the potential societal impacts of rapid sea level rise and should result in critically needed improvements in characterizing and predicting the behavior of coupled ocean-ice systems. It is a contribution to the International Polar Year and was endorsed by the International Council for Science as a component of the \u0027Multidisciplinary Study of the Amundsen Sea Embayment\u0027 proposal #258 of the honeycomb of endorsed IPY activities. The research involves substantial international partnerships with the British Antarctic Survey and the University of Bristol in the UK. The investigators will partner with the previously funded \u0027Polar Palooza\u0027 education and outreach program in addition to undertaking a diverse set of outreach activities of their own. Eight graduate students and one undergraduate as well as one post doc will be integrated into this research project.\n", "east": 166.25, "geometry": ["POINT(166.25 -77.42)"], "keywords": "Antarctica; Atmosphere; Cryosphere; McMurdo; Meteorology; Oceans; Ross Island; Southern Ocean", "locations": "McMurdo; Ross Island; Southern Ocean; Antarctica", "north": -77.42, "nsf_funding_programs": null, "persons": "McPhee, Miles G.", "project_titles": "Collaborative Research; IPY: Ocean-Ice Interaction in the Amundsen Sea sector of West Antarctica", "projects": [{"proj_uid": "p0000043", "repository": "USAP-DC", "title": "Collaborative Research; IPY: Ocean-Ice Interaction in the Amundsen Sea sector of West Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.42, "title": "Ocean-Ice Interaction in the Amundsen Sea Sector of West Antarctica", "uid": "600072", "west": 166.25}, {"awards": "0538195 Marone, Chris; 0424589 Gogineni, S. Prasad; 0440523 Baker, Ian", "bounds_geometry": ["POINT(-147.753056 61.781667)", "POINT(147.758889 61.779444)", "POINT(-83.006944 40.067222)"], "date_created": "Wed, 14 Apr 2010 00:00:00 GMT", "description": "This data set includes the results of laboratory experiments examining the constitutive properties of subglacial till, under dynamic stressing. The data include the results of shear strain and stress experiments. Testing was carried out in a servo-controlled biaxial shear device under controlled temperature and stress conditions, allowing both sliding and microstructural processes to be studied in detail. Till samples were collected from Matanuska, Alaska and from Caesar till at the Laurentide Ice Sheet. \n\nThe data are available via FTP in ASCII text format (.txt).", "east": 147.758889, "geometry": ["POINT(-147.753056 61.781667)", "POINT(147.758889 61.779444)", "POINT(-83.006944 40.067222)"], "keywords": "Cryosphere; Geology/Geophysics - Other; Glaciers/Ice Sheet; Shear Stress; Solid Earth; Strain", "locations": null, "north": 61.781667, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Marone, Chris; Anandakrishnan, Sridhar", "project_titles": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till", "projects": [{"proj_uid": "p0000554", "repository": "USAP-DC", "title": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": 40.067222, "title": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till", "uid": "609460", "west": -147.753056}, {"awards": "0228842 Grew, Edward", "bounds_geometry": ["POLYGON((76 -69.3,76.05 -69.3,76.1 -69.3,76.15 -69.3,76.2 -69.3,76.25 -69.3,76.3 -69.3,76.35 -69.3,76.4 -69.3,76.45 -69.3,76.5 -69.3,76.5 -69.32,76.5 -69.34,76.5 -69.36,76.5 -69.38,76.5 -69.4,76.5 -69.42,76.5 -69.44,76.5 -69.46,76.5 -69.48,76.5 -69.5,76.45 -69.5,76.4 -69.5,76.35 -69.5,76.3 -69.5,76.25 -69.5,76.2 -69.5,76.15 -69.5,76.1 -69.5,76.05 -69.5,76 -69.5,76 -69.48,76 -69.46,76 -69.44,76 -69.42,76 -69.4,76 -69.38,76 -69.36,76 -69.34,76 -69.32,76 -69.3))"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role and fate of Boron in high-grade metamorphic rocks of the Larsemann Hills region of Antarctica. Trace elements provide valuable information on the changes sedimentary rocks undergo as temperature and pressure increase during burial. One such element, boron, is particularly sensitive to increasing temperature because of its affinity for aqueous fluids, which are lost as rocks are buried. Boron contents of unmetamorphosed pelitic sediments range from 20 to over 200 parts per million, but rarely exceed 5 parts per million in rocks subjected to conditions of the middle and lower crust, that is, temperatures of 700 degrees C or more in the granulite-facies, which is characterized by very low water activities at pressures of 5 to 10 kbar (18-35 km burial). Devolatization reactions with loss of aqueous fluid and partial melting with removal of melt have been cited as primary causes for boron depletion under granulite-facies conditions. Despite the pervasiveness of both these processes, rocks rich in boron are locally found in the granulite-facies, that is, there are mechanisms for retaining boron during the metamorphic process. The Larsemann Hills, Prydz Bay, Antarctica, are a prime example. More than 20 lenses and layered bodies containing four borosilicate mineral species crop out over a 50 square kilometer area, which thus would be well suited for research on boron-rich granulite-facies metamorphic rocks. While most investigators have focused on the causes for loss of boron, this work will investigate how boron is retained during high-grade metamorphism. Field observations and mapping in the Larsemann Hills, chemical analyses of minerals and their host rocks, and microprobe age dating will be used to identify possible precursors and deduce how the precursor materials recrystallized into borosilicate rocks under granulite-facies conditions. \n\nThe working hypothesis is that high initial boron content facilitates retention of boron during metamorphism because above a certain threshold boron content, a mechanism \u0027kicks in\u0027 that facilitates retention of boron in metamorphosed rocks. For example, in a rock with large amounts of the borosilicate tourmaline, such as stratabound tourmalinite, the breakdown of tourmaline to melt could result in the formation of prismatine and grandidierite, two borosilicates found in the Larsemann Hills. This situation is rarely observed in rocks with modest boron content, in which breakdown of tourmaline releases boron into partial melts, which in turn remove boron when they leave the system. Stratabound tourmalinite is associated with manganese-rich quartzite, phosphorus-rich rocks and sulfide concentrations that could be diagnostic for recognizing a tourmalinite protolith in a highly metamorphosed complex where sedimentary features have been destroyed by deformation. Because partial melting plays an important role in the fate of boron during metamorphism, our field and laboratory research will focus on the relationship between the borosilicate units, granite pegmatites and other granitic intrusives. The results of our study will provide information on cycling of boron at deeper levels in the Earth\u0027s crust and on possible sources of boron for granites originating from deep-seated rocks. An undergraduate student will participate in the electron microprobe age-dating of monazite and xenotime as part of a senior project, thereby integrating the proposed research into the educational mission of the University of Maine. In response to a proposal for fieldwork, the Australian Antarctic Division, which maintains Davis station near the Larsemann Hills, has indicated that they will support the Antarctic fieldwork.", "east": 76.5, "geometry": ["POINT(76.25 -69.4)"], "keywords": "Antarctica; Chemistry:Rock; Geochemistry; Geochronology; Solid Earth", "locations": "Antarctica", "north": -69.3, "nsf_funding_programs": null, "persons": "Grew, Edward", "project_titles": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?", "projects": [{"proj_uid": "p0000431", "repository": "USAP-DC", "title": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.5, "title": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?", "uid": "600030", "west": 76.0}, {"awards": "0538195 Marone, Chris", "bounds_geometry": null, "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "This award supports a project to conduct laboratory experiments and numerical modeling to determine the constitutive properties of subglacial till under dynamic stressing and to test the hypothesis that granular properties of till are sufficient, when coupled elastically to a large ice stream, to reproduce the field observations of triggered slip and subglacial seismicity. Testing will be carried out in a servo-controlled biaxial shear device under controlled temperature and stress conditions, which will allow both sliding and microstructural processes to be studied in detail. The main focus of the work will be on laboratory measurements. In addition, we will construct continuum models to evaluate whether our results can predict complex ice sheet motions and observed characteristics of subglacial seismicity. In terms of broader impacts, the proposed work will encourage interactions between the rock-mechanics and glaciology communities and will bring together members of different scientific backgrounds and vocabularies, but similar problems and data. The project will train undergraduate and graduate students at Penn State University and the scientists involved plan to give presentations to grade school classes, scout groups, and at community open houses. Results will be presented at professional meetings and will be published in a timely manner. The work will result in a better understanding of glacial motion and the physics of earthquake slip, which is essential for understanding ice sheet dynamics and earthquake hazard.", "east": null, "geometry": null, "keywords": "Antarctica; Cryosphere; Glacial Till; Glaciers/Ice Sheet; lab experiment; Marine Sediments; Physical Properties; Solid Earth", "locations": "Antarctica", "north": null, "nsf_funding_programs": null, "persons": "Marone, Chris; Anandakrishnan, Sridhar", "project_titles": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till", "projects": [{"proj_uid": "p0000554", "repository": "USAP-DC", "title": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till", "uid": "600054", "west": null}, {"awards": "9615502 Harrison, William", "bounds_geometry": ["POINT(-148.693 -81.595)", "POINT(-148.822 -81.655)"], "date_created": "Thu, 22 Feb 2007 00:00:00 GMT", "description": "At the Siple Dome area of Antarctica, much of the ice flow is vertical, which causes vertical ice deformation. To measure this phenomenon, the investigators used a method known as vertical strain rate. This project was a part of the West Antarctic Ice Sheet Cores (WAISCORES) project for deep ice coring in West Antarctica. WAISCORES is supported by the Office of Polar Programs (OPP), National Science Foundation (NSF).\n\nThis data set consists of a table of long-term average strain rates measured between 1999 and 2002 at Siple Dome, Antarctica. The measurements were taken in hot-water boreholes by bridge gauges. Data are available in tab-delimited ASCII text format or PDF via FTP.", "east": -148.693, "geometry": ["POINT(-148.693 -81.595)", "POINT(-148.822 -81.655)"], "keywords": "Antarctica; Cryosphere; Geodetic; Geology/Geophysics - Other; Glaciers/Ice Sheet; Glaciology; Siple Dome; Siple Dome Ice Core; Strain; WAISCORES", "locations": "Siple Dome; Antarctica", "north": -81.595, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Harrison, William; Morack, James; Waddington, Edwin D.; Pettit, Erin; Zumberge, Mark; Elsberg, Daniel", "project_titles": "Ice Dynamics, the Flow Law, and Vertical Strain at Siple Dome", "projects": [{"proj_uid": "p0000601", "repository": "USAP-DC", "title": "Ice Dynamics, the Flow Law, and Vertical Strain at Siple Dome"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": -81.655, "title": "Vertical Strain at Siple Dome, Antarctica, 1999-2002", "uid": "609214", "west": -148.822}, {"awards": "0135989 Wilen, Larry", "bounds_geometry": ["POINT(148 81)"], "date_created": "Wed, 02 Mar 2005 00:00:00 GMT", "description": "This data set contains measurements of the orientation and deformation of the crystal c-axes (fabric) of ice core samples collected from the Siple Dome Ice Core A, Antarctica (81\u00b0S, 148\u00b0W) between 22.764 m and 992.385 m in depth. The instrument used for the measurements consists of a fiber-optic white light source, one fixed black-and-white video camera, and four rotation stages. The data are in ASCII tab-delimited text format and are available via FTP.", "east": 148.0, "geometry": ["POINT(148 81)"], "keywords": "Antarctica; Cryosphere; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Siple Dome; Siple Dome Ice Core", "locations": "Siple Dome; Antarctica", "north": 81.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Wilen, Larry", "project_titles": "Collaborative Research: Fabric and Texture Characteristics of Micro-Physical Processes in Ice", "projects": [{"proj_uid": "p0000134", "repository": "USAP-DC", "title": "Collaborative Research: Fabric and Texture Characteristics of Micro-Physical Processes in Ice"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Siple Dome Ice Core", "south": 81.0, "title": "Ice Fabric Characteristics: Siple Dome, A Core", "uid": "609255", "west": 148.0}]
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Dataset Title/Abstract/Map | NSF Award(s) | Date Created | PIs / Scientists | Project Links | Abstract | Bounds Geometry | Geometry | Selected | Visible |
---|---|---|---|---|---|---|---|---|---|
Dataset for Tidal modulation of ice streams: Effect of periodic sliding velocity on ice friction and healing
|
1245871 |
2021-12-23 | McCarthy, Christine M.; Skarbek, Rob; Savage, Heather |
Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers |
This data set contains text files for the experimental logs of ice-on-rock friction experiments that were conducted in a double direct shear apparatus at temperatures of -16.4 C to -2 C. There are eleven files (C28-C34, C39-C41, and C44). Each file contains 4 columns of data that correspond to time (s), vertical displacement (microns), friction, and velocity. The data were prepared by converting voltages from experimental feedbacks, to appropriate units using calibrations, as conducted separate. Miscellaneous loading and unloading data were removed and the data was filtered modestly (100 point moving average filter in matlab). The data set includes all information needed to plot friction or velocity vs. time or displacement from the beginning to end of the run. | [] | [] | false | false |
Rate-state friction parameters for ice-on-rock oscillation experiments
|
1245871 |
2021-07-30 | Skarbek, Rob; McCarthy, Christine M.; Savage, Heather |
Laboratory Study of Ice Deformation under Tidal Loading Conditions with Application to Antarctic Glaciers |
This data set contains rate and state frictional parameters for ice-on-rock friction experiments that were conducted in a double direct shear apparatus as temperatures of -16.4 C to -2 C. The frictional parameters were deteremined by directly fitting the frictional response to controlled, harmonic oscillations in load point velocity. The data set includes all information needed to reproduce the fits, as well as tables of the frictional parameters for both the aging and slip law forms of frictional state evolution. | [] | [] | false | false |
MOA-derived Structural Feature Map of the Ross Ice Shelf
|
0440670 |
2021-02-19 | Hulbe, Christina; Ledoux, Christine; Forbes, Martin |
Collaborative Research: Using Fracture Patterns and Ice Thickness to Study the History and Dynamics of Grounding Line Migration and Shutdown of Kamb and Whillans Ice Streams |
The surface of the Ross Ice Shelf (RIS) is textured by flow stripes, crevasses and other fea- tures related to ice flow and deformation. Here, moderate resolution optical satellite images are used to map and classify regions of the RIS characterized by different surface textures. Because the textures arise from ice deformation, the map is used to identify structural provinces with common deformation history. We classify four province types: regions associated with large outlet glaciers, shear zones, exten- sion downstream of obstacles and suture zones between provinces with different upstream sources. Adjacent provinces with contrasting histories are in some locations deforming at different rates, suggest- ing that our province map is also an ice fabric map. Structural provinces have more complicated shapes in the part of the ice shelf fed by West Antarctic ice streams than in the part fed by outlet glaciers from the Transantarctic Mountains. The map may be used to infer past variations in stress conditions and flow events that cannot be inferred from flow traces alone. | ["POLYGON((-180 -77,-177 -77,-174 -77,-171 -77,-168 -77,-165 -77,-162 -77,-159 -77,-156 -77,-153 -77,-150 -77,-150 -77.9,-150 -78.8,-150 -79.7,-150 -80.6,-150 -81.5,-150 -82.4,-150 -83.3,-150 -84.2,-150 -85.1,-150 -86,-153 -86,-156 -86,-159 -86,-162 -86,-165 -86,-168 -86,-171 -86,-174 -86,-177 -86,180 -86,177.5 -86,175 -86,172.5 -86,170 -86,167.5 -86,165 -86,162.5 -86,160 -86,157.5 -86,155 -86,155 -85.1,155 -84.2,155 -83.3,155 -82.4,155 -81.5,155 -80.6,155 -79.7,155 -78.8,155 -77.9,155 -77,157.5 -77,160 -77,162.5 -77,165 -77,167.5 -77,170 -77,172.5 -77,175 -77,177.5 -77,-180 -77))"] | ["POINT(-177.5 -81.5)"] | false | false |
South Pole (SPICEcore) Borehole Deformation
|
1142167 |
2020-05-04 | Pettit, Erin |
Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica |
Acoustic Televiewer measures borehole shape and tilt. These data were collected to study detailed borehole deformation with respect to ice properties to expand our understanding of the flow law for ice. | ["POINT(-180 -90)"] | ["POINT(-180 -90)"] | false | false |
Ocean-Ice Interaction in the Amundsen Sea Sector of West Antarctica
|
0732804 |
2014-01-01 | McPhee, Miles G. |
Collaborative Research; IPY: Ocean-Ice Interaction in the Amundsen Sea sector of West Antarctica |
The Office of Polar Programs, Antarctic Integrated and System Science Program has made this award to support an interdisciplinary study of the effects of the ocean on the stability of glacial ice in the most dynamic region the West Antarctic Ice Sheet, namely the Pine Island Glacier in the Amundsen Sea Embayment. The collaborative project builds on the knowledge gained by the highly successful West Antarctic Ice Sheet program and is being jointly sponsored with NASA. Recent observations indicate a significant ice loss, equivalent to 10% of the ongoing increase in sea-level rise, in this region. These changes are largest along the coast and propagate rapidly inland, indicating the critical impact of the ocean on ice sheet stability in the region. While a broad range of remote sensing and ground-based instrumentation is available to characterize changes of the ice surface and internal structure (deformation, ice motion, melt) and the shape of the underlying sediment and rock bed, instrumentation has yet to be successfully deployed for observing boundary layer processes of the ocean cavity which underlies the floating ice shelf and where rapid melting is apparently occurring. Innovative, mini ocean sensors that can be lowered through boreholes in the ice shelf (about 500 m thick) will be developed and deployed to automatically provide ocean profiling information over at least three years. Their data will be transmitted through a conducting cable frozen in the borehole to the surface where it will be further transmitted via satellite to a laboratory in the US. Geophysical and remote sensing methods (seismic, GPS, altimetry, stereo imaging, radar profiling) will be applied to map the geometry of the ice shelf, the shape of the sub ice-shelf cavity, the ice surface geometry and deformations within the glacial ice. To integrate the seismic, glaciological and oceanographic observations, a new 3-dimensional coupled ice-ocean model is being developed which will be the first of its kind. NASA is supporting satellite based research and the deployment of a robotic-camera system to explore the environment in the ocean cavity underlying the ice shelf and NSF is supporting all other aspects of this study. Broader impacts: This project is motivated by the potential societal impacts of rapid sea level rise and should result in critically needed improvements in characterizing and predicting the behavior of coupled ocean-ice systems. It is a contribution to the International Polar Year and was endorsed by the International Council for Science as a component of the 'Multidisciplinary Study of the Amundsen Sea Embayment' proposal #258 of the honeycomb of endorsed IPY activities. The research involves substantial international partnerships with the British Antarctic Survey and the University of Bristol in the UK. The investigators will partner with the previously funded 'Polar Palooza' education and outreach program in addition to undertaking a diverse set of outreach activities of their own. Eight graduate students and one undergraduate as well as one post doc will be integrated into this research project. | ["POINT(166.25 -77.42)"] | ["POINT(166.25 -77.42)"] | false | false |
Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till
|
0538195 0424589 0440523 |
2010-04-14 | Marone, Chris; Anandakrishnan, Sridhar |
Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till |
This data set includes the results of laboratory experiments examining the constitutive properties of subglacial till, under dynamic stressing. The data include the results of shear strain and stress experiments. Testing was carried out in a servo-controlled biaxial shear device under controlled temperature and stress conditions, allowing both sliding and microstructural processes to be studied in detail. Till samples were collected from Matanuska, Alaska and from Caesar till at the Laurentide Ice Sheet. The data are available via FTP in ASCII text format (.txt). | ["POINT(-147.753056 61.781667)", "POINT(147.758889 61.779444)", "POINT(-83.006944 40.067222)"] | ["POINT(-147.753056 61.781667)", "POINT(147.758889 61.779444)", "POINT(-83.006944 40.067222)"] | false | false |
Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?
|
0228842 |
2009-01-01 | Grew, Edward |
Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust? |
This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role and fate of Boron in high-grade metamorphic rocks of the Larsemann Hills region of Antarctica. Trace elements provide valuable information on the changes sedimentary rocks undergo as temperature and pressure increase during burial. One such element, boron, is particularly sensitive to increasing temperature because of its affinity for aqueous fluids, which are lost as rocks are buried. Boron contents of unmetamorphosed pelitic sediments range from 20 to over 200 parts per million, but rarely exceed 5 parts per million in rocks subjected to conditions of the middle and lower crust, that is, temperatures of 700 degrees C or more in the granulite-facies, which is characterized by very low water activities at pressures of 5 to 10 kbar (18-35 km burial). Devolatization reactions with loss of aqueous fluid and partial melting with removal of melt have been cited as primary causes for boron depletion under granulite-facies conditions. Despite the pervasiveness of both these processes, rocks rich in boron are locally found in the granulite-facies, that is, there are mechanisms for retaining boron during the metamorphic process. The Larsemann Hills, Prydz Bay, Antarctica, are a prime example. More than 20 lenses and layered bodies containing four borosilicate mineral species crop out over a 50 square kilometer area, which thus would be well suited for research on boron-rich granulite-facies metamorphic rocks. While most investigators have focused on the causes for loss of boron, this work will investigate how boron is retained during high-grade metamorphism. Field observations and mapping in the Larsemann Hills, chemical analyses of minerals and their host rocks, and microprobe age dating will be used to identify possible precursors and deduce how the precursor materials recrystallized into borosilicate rocks under granulite-facies conditions. The working hypothesis is that high initial boron content facilitates retention of boron during metamorphism because above a certain threshold boron content, a mechanism 'kicks in' that facilitates retention of boron in metamorphosed rocks. For example, in a rock with large amounts of the borosilicate tourmaline, such as stratabound tourmalinite, the breakdown of tourmaline to melt could result in the formation of prismatine and grandidierite, two borosilicates found in the Larsemann Hills. This situation is rarely observed in rocks with modest boron content, in which breakdown of tourmaline releases boron into partial melts, which in turn remove boron when they leave the system. Stratabound tourmalinite is associated with manganese-rich quartzite, phosphorus-rich rocks and sulfide concentrations that could be diagnostic for recognizing a tourmalinite protolith in a highly metamorphosed complex where sedimentary features have been destroyed by deformation. Because partial melting plays an important role in the fate of boron during metamorphism, our field and laboratory research will focus on the relationship between the borosilicate units, granite pegmatites and other granitic intrusives. The results of our study will provide information on cycling of boron at deeper levels in the Earth's crust and on possible sources of boron for granites originating from deep-seated rocks. An undergraduate student will participate in the electron microprobe age-dating of monazite and xenotime as part of a senior project, thereby integrating the proposed research into the educational mission of the University of Maine. In response to a proposal for fieldwork, the Australian Antarctic Division, which maintains Davis station near the Larsemann Hills, has indicated that they will support the Antarctic fieldwork. | ["POLYGON((76 -69.3,76.05 -69.3,76.1 -69.3,76.15 -69.3,76.2 -69.3,76.25 -69.3,76.3 -69.3,76.35 -69.3,76.4 -69.3,76.45 -69.3,76.5 -69.3,76.5 -69.32,76.5 -69.34,76.5 -69.36,76.5 -69.38,76.5 -69.4,76.5 -69.42,76.5 -69.44,76.5 -69.46,76.5 -69.48,76.5 -69.5,76.45 -69.5,76.4 -69.5,76.35 -69.5,76.3 -69.5,76.25 -69.5,76.2 -69.5,76.15 -69.5,76.1 -69.5,76.05 -69.5,76 -69.5,76 -69.48,76 -69.46,76 -69.44,76 -69.42,76 -69.4,76 -69.38,76 -69.36,76 -69.34,76 -69.32,76 -69.3))"] | ["POINT(76.25 -69.4)"] | false | false |
Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till
|
0538195 |
2009-01-01 | Marone, Chris; Anandakrishnan, Sridhar |
Laboratory Study of Stick-Slip Behavior and Deformation Mechanics of Subglacial Till |
This award supports a project to conduct laboratory experiments and numerical modeling to determine the constitutive properties of subglacial till under dynamic stressing and to test the hypothesis that granular properties of till are sufficient, when coupled elastically to a large ice stream, to reproduce the field observations of triggered slip and subglacial seismicity. Testing will be carried out in a servo-controlled biaxial shear device under controlled temperature and stress conditions, which will allow both sliding and microstructural processes to be studied in detail. The main focus of the work will be on laboratory measurements. In addition, we will construct continuum models to evaluate whether our results can predict complex ice sheet motions and observed characteristics of subglacial seismicity. In terms of broader impacts, the proposed work will encourage interactions between the rock-mechanics and glaciology communities and will bring together members of different scientific backgrounds and vocabularies, but similar problems and data. The project will train undergraduate and graduate students at Penn State University and the scientists involved plan to give presentations to grade school classes, scout groups, and at community open houses. Results will be presented at professional meetings and will be published in a timely manner. The work will result in a better understanding of glacial motion and the physics of earthquake slip, which is essential for understanding ice sheet dynamics and earthquake hazard. | [] | [] | false | false |
Vertical Strain at Siple Dome, Antarctica, 1999-2002
|
9615502 |
2007-02-22 | Harrison, William; Morack, James; Waddington, Edwin D.; Pettit, Erin; Zumberge, Mark; Elsberg, Daniel |
Ice Dynamics, the Flow Law, and Vertical Strain at Siple Dome |
At the Siple Dome area of Antarctica, much of the ice flow is vertical, which causes vertical ice deformation. To measure this phenomenon, the investigators used a method known as vertical strain rate. This project was a part of the West Antarctic Ice Sheet Cores (WAISCORES) project for deep ice coring in West Antarctica. WAISCORES is supported by the Office of Polar Programs (OPP), National Science Foundation (NSF). This data set consists of a table of long-term average strain rates measured between 1999 and 2002 at Siple Dome, Antarctica. The measurements were taken in hot-water boreholes by bridge gauges. Data are available in tab-delimited ASCII text format or PDF via FTP. | ["POINT(-148.693 -81.595)", "POINT(-148.822 -81.655)"] | ["POINT(-148.693 -81.595)", "POINT(-148.822 -81.655)"] | false | false |
Ice Fabric Characteristics: Siple Dome, A Core
|
0135989 |
2005-03-02 | Wilen, Larry |
Collaborative Research: Fabric and Texture Characteristics of Micro-Physical Processes in Ice |
This data set contains measurements of the orientation and deformation of the crystal c-axes (fabric) of ice core samples collected from the Siple Dome Ice Core A, Antarctica (81°S, 148°W) between 22.764 m and 992.385 m in depth. The instrument used for the measurements consists of a fiber-optic white light source, one fixed black-and-white video camera, and four rotation stages. The data are in ASCII tab-delimited text format and are available via FTP. | ["POINT(148 81)"] | ["POINT(148 81)"] | false | false |