USAP-DC

{"dp_type": "Dataset", "free_text": "Subglacial Bedrock"}

[{"awards": "1738989 Venturelli, Ryan", "bounds_geometry": ["POINT(-110.96038 -75.21526)"], "date_created": "Mon, 10 Jul 2023 00:00:00 GMT", "description": "Included in this dataset are in situ carbon-14 concentrations for a series of bedrock cores recovered from the subglacial extension of Kay Peak, a grounding-line-proximal ridge of the volcanic edifice Mount Murphy (near Thwaites and Pope glaciers). Concentrations measured in these bedrock samples have been used in the associated publication to demonstrate that the Thwaites-Pope glacier system was thinner in the Holocene than it is today. ", "east": -110.96038, "geometry": ["POINT(-110.96038 -75.21526)"], "keywords": "Antarctica; Cosmogenic Radionuclides; Mount Murphy; Subglacial Bedrock", "locations": "Mount Murphy; Antarctica", "north": -75.21526, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Venturelli, Ryan; Goehring, Brent; Balco, Gregory", "project_titles": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System", "projects": [{"proj_uid": "p0010165", "repository": "USAP-DC", "title": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Thwaites (ITGC)", "south": -75.21526, "title": "In situ 14C data from a subglacial bedrock core near Pope and Thwaites glaciers", "uid": "601705", "west": -110.96038}, {"awards": "2317097 Venturelli, Ryan", "bounds_geometry": ["POLYGON((-99.793 -74.857,-99.7882 -74.857,-99.7834 -74.857,-99.77860000000001 -74.857,-99.77380000000001 -74.857,-99.769 -74.857,-99.7642 -74.857,-99.7594 -74.857,-99.75460000000001 -74.857,-99.74980000000001 -74.857,-99.745 -74.857,-99.745 -74.8583,-99.745 -74.8596,-99.745 -74.8609,-99.745 -74.8622,-99.745 -74.8635,-99.745 -74.8648,-99.745 -74.8661,-99.745 -74.8674,-99.745 -74.8687,-99.745 -74.87,-99.74980000000001 -74.87,-99.75460000000001 -74.87,-99.7594 -74.87,-99.7642 -74.87,-99.769 -74.87,-99.77380000000001 -74.87,-99.77860000000001 -74.87,-99.7834 -74.87,-99.7882 -74.87,-99.793 -74.87,-99.793 -74.8687,-99.793 -74.8674,-99.793 -74.8661,-99.793 -74.8648,-99.793 -74.8635,-99.793 -74.8622,-99.793 -74.8609,-99.793 -74.8596,-99.793 -74.8583,-99.793 -74.857))"], "date_created": "Fri, 24 Mar 2023 00:00:00 GMT", "description": "This data set contains unprocessed radar profiles collected with a GSSI 200 MHz Hyperstacking antenna near Winkie Nunatak, West Antarctica. This data was collected to estimate depth-to-bedrock along a subglacial ridge line at depths between 20 - 120 meters. ", "east": -99.745, "geometry": ["POINT(-99.769 -74.8635)"], "keywords": "Antarctica; Ice Penetrating Radar; Pine Island Glacier; Subglacial Bedrock", "locations": "Pine Island Glacier; Antarctica", "north": -74.857, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Braddock, Scott", "project_titles": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System", "projects": [{"proj_uid": "p0010165", "repository": "USAP-DC", "title": "NSF-NERC: Geological History Constraints on the Magnitude of Grounding Line Retreat in the Thwaites Glacier System"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Thwaites (ITGC)", "south": -74.87, "title": "200 MHz ground-penetrating radar from Winkie Nunatak, West Antarctica", "uid": "601677", "west": -99.793}, {"awards": "1341728 Stone, John", "bounds_geometry": ["POLYGON((-86.3 -81,-86.17 -81,-86.04 -81,-85.91 -81,-85.78 -81,-85.65 -81,-85.52 -81,-85.39 -81,-85.26 -81,-85.13 -81,-85 -81,-85 -81.03,-85 -81.06,-85 -81.09,-85 -81.12,-85 -81.15,-85 -81.18,-85 -81.21,-85 -81.24,-85 -81.27,-85 -81.3,-85.13 -81.3,-85.26 -81.3,-85.39 -81.3,-85.52 -81.3,-85.65 -81.3,-85.78 -81.3,-85.91 -81.3,-86.04 -81.3,-86.17 -81.3,-86.3 -81.3,-86.3 -81.27,-86.3 -81.24,-86.3 -81.21,-86.3 -81.18,-86.3 -81.15,-86.3 -81.12,-86.3 -81.09,-86.3 -81.06,-86.3 -81.03,-86.3 -81))"], "date_created": "Wed, 09 Oct 2019 00:00:00 GMT", "description": "This data set contains measurements of cosmic-ray-produced Be-10 and Al-26 in quartz from the RB-2 core, recovered from bedrock at a depth of 150 m below the West Antarctic Ice Sheet surface in the Pirrit Hills. The core site is located at latitude S81.09948, longitude W85.15694. Core length is approximately 8 meters. Lithology is A-type granite, similar in composition to bedrock exposed on nearby Harter Nunatak and other mountains in the Pirrit Hills (Lee et al. Geosci. J. 16, 421-433). Samples were processed at the University of Washington Cosmogenic Nuclide Laboratory. Chemical processing and purification methods are described at http://depts.washington.edu/cosmolab/chem.shtml. Beryllium isotope ratios were measured at the Lawrence Livermore Center for Accelerator Mass Spectrometry (LLNL-CAMS) relative to the KNSTD-Be-01-5-4 standard, assuming a standard Be-10/Be-9 ratio of 2.851E-12 (07KNSTD normalization). Aluminum isotope ratios were measured at PRIME Lab, Purdue University, relative to the KNSTD-Al-01-5-2 standard, assuming a standard Al-26/Al-27 ratio of 1.818E-12 (KNSTD normalization). Uncertainties are 1-sigma and include full AMS errors and all known sources of laboratory uncertainty.", "east": -85.0, "geometry": ["POINT(-85.65 -81.15)"], "keywords": "Aluminum-26; Antarctica; Be-10; Bedrock Core; Beryllium-10; Chemistry:rock; Chemistry:Rock; Cosmogenic; Cosmogenic Dating; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Isotope Data; Pirrit Hills; Rocks; Solid Earth; Subglacial Bedrock", "locations": "Pirrit Hills; Antarctica", "north": -81.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Stone, John", "project_titles": "EXPROBE-WAIS: Exposed Rock Beneath the West Antarctic Ice Sheet, A Test for Interglacial Ice Sheet Collapse", "projects": [{"proj_uid": "p0010057", "repository": "USAP-DC", "title": "EXPROBE-WAIS: Exposed Rock Beneath the West Antarctic Ice Sheet, A Test for Interglacial Ice Sheet Collapse"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -81.3, "title": "Pirrit Hills subglacial bedrock core RB-2, cosmogenic Be-10, Al-26 data", "uid": "601214", "west": -86.3}, {"awards": "1142162 Stone, John", "bounds_geometry": ["POLYGON((-104.14 -81.07,-102.24 -81.07,-100.34 -81.07,-98.44 -81.07,-96.54 -81.07,-94.64 -81.07,-92.74 -81.07,-90.84 -81.07,-88.94 -81.07,-87.04 -81.07,-85.14 -81.07,-85.14 -81.207,-85.14 -81.344,-85.14 -81.481,-85.14 -81.618,-85.14 -81.755,-85.14 -81.892,-85.14 -82.029,-85.14 -82.166,-85.14 -82.303,-85.14 -82.44,-87.04 -82.44,-88.94 -82.44,-90.84 -82.44,-92.74 -82.44,-94.64 -82.44,-96.54 -82.44,-98.44 -82.44,-100.34 -82.44,-102.24 -82.44,-104.14 -82.44,-104.14 -82.303,-104.14 -82.166,-104.14 -82.029,-104.14 -81.892,-104.14 -81.755,-104.14 -81.618,-104.14 -81.481,-104.14 -81.344,-104.14 -81.207,-104.14 -81.07))"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "This award supports a reconnaissance geological and radar-sounding study of promising sites in West Antarctica for a future project to measure cosmogenic nuclides in subglacial bedrock. Field work will take place in the Whitmore Mountains, close to the WAIS divide, and on the Nash and Pirrit Hills, downflow from the divide in the Weddell Sea drainage. At each site geological indicators of higher (and lower) ice levels in the past will be mapped and evidence of subglacial erosion or its absence will be documented. Elevation transects of both glacial erratics and adjacent bedrock samples will be collected to establish the timing of recent deglaciation at the sites and provide a complement to similar measurements on material from depth transects obtained by future subglacial drilling. At each site, bedrock ridges will be traced into the subsurface with closely-spaced ice-penetrating radar surveys, using a combination of instruments and frequencies to obtain the highest possible surface detail. Collectively the results will define prospective sites for subglacial sampling, and maximize the potential information to be obtained from such samples in future studies. The intellectual merit of this project is that measurements of cosmogenic nuclides in subglacial bedrock hold promise for resolving the questions of whether the West Antarctic ice sheet collapsed completely in the past, whether it is prone to repeated large deglaciations, and if so, what is their magnitude and frequency. Such studies will require careful choice of targets, to locate sites where bedrock geology is favorable, cosmogenic nuclide records are likely to have been protected from subglacial erosion, and the local ice-surface response is indicative of large-scale ice sheet behavior. The broader impacts of this work include helping to determine whether subglacial surfaces in West Antarctica were ever exposed to cosmic rays, which will provide unambiguous evidence for or against a smaller ice sheet in the past. This is an important step towards establishing whether the WAIS is vulnerable to collapse in future, and will ultimately help to address uncertainty in forecasting sea level change. The results will also provide ground truth for models of ice-sheet dynamics and long-term ice sheet evolution, and will help researchers use these models to identify paleoclimate conditions responsible for WAIS deglaciation. The education and training of students (both undergraduate and graduate students) will play an important role in the project, which will involve Antarctic fieldwork, technically challenging labwork, data collection and interpretation, and communication of the outcome to scientists and the general public.", "east": -85.14, "geometry": ["POINT(-94.64 -81.755)"], "keywords": "Antarctica; Be-10; Chemistry:rock; Chemistry:Rock; Cosmogenic Dating; Glaciology; Nunataks; Sample/collection Description; Sample/Collection Description; Solid Earth; Whitmore Mountains", "locations": "Whitmore Mountains; Antarctica", "north": -81.07, "nsf_funding_programs": null, "persons": "Stone, John", "project_titles": "Glacial-interglacial History of West Antarctic Nunataks and Site Reconnaissance for Subglacial Bedrock Sampling", "projects": [{"proj_uid": "p0000335", "repository": "USAP-DC", "title": "Glacial-interglacial History of West Antarctic Nunataks and Site Reconnaissance for Subglacial Bedrock Sampling"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -82.44, "title": "Glacial-interglacial History of West Antarctic Nunataks and Site Reconnaissance for Subglacial Bedrock Sampling", "uid": "600162", "west": -104.14}]

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