USAP-DC

{"dp_type": "Dataset", "free_text": "Horizontal Ice Core"}

[{"awards": "1245821 Brook, Edward J.; 1246148 Severinghaus, Jeffrey; 1245659 Petrenko, Vasilii", "bounds_geometry": ["POLYGON((161 -77.7,161.1 -77.7,161.2 -77.7,161.3 -77.7,161.4 -77.7,161.5 -77.7,161.6 -77.7,161.7 -77.7,161.8 -77.7,161.9 -77.7,162 -77.7,162 -77.71000000000001,162 -77.72,162 -77.73,162 -77.74,162 -77.75,162 -77.76,162 -77.77,162 -77.78,162 -77.78999999999999,162 -77.8,161.9 -77.8,161.8 -77.8,161.7 -77.8,161.6 -77.8,161.5 -77.8,161.4 -77.8,161.3 -77.8,161.2 -77.8,161.1 -77.8,161 -77.8,161 -77.78999999999999,161 -77.78,161 -77.77,161 -77.76,161 -77.75,161 -77.74,161 -77.73,161 -77.72,161 -77.71000000000001,161 -77.7))"], "date_created": "Tue, 23 Aug 2022 00:00:00 GMT", "description": "High-precision carbon isotope data (d13C-CO2) show atmospheric CO2 during Marine Isotope Stage 4 (MIS 4, ~70.5-59 ka) was controlled by a succession of millennial-scale processes. Enriched d13C-CO2 during peak glaciation suggests increased ocean carbon storage. Variations in d13C-CO2 in early MIS4 suggest multiple processes were active during CO2 drawdown, potentially including decreased land carbon and decreased Southern Ocean air-sea gas exchange superposed on increased ocean carbon storage. CO2 remained low during MIS 4 while d13C-CO2 fluctuations suggest changes in Southern Ocean and North Atlantic air-sea gas exchange. A 7 ppm increase in CO2 at the onset of Dansgaard-Oeschger event 19 (72.1 ka) and a 22 ppm increase in CO2 during late MIS 4 (Heinrich Stadial 6, ~63.5-60 ka) involved additions of isotopically light carbon to the atmosphere. The terrestrial biosphere and Southern Ocean air-sea gas exchange are possible sources, with the latter event also involving decreased ocean carbon storage.", "east": 162.0, "geometry": ["POINT(161.5 -77.75)"], "keywords": "Antarctica; Taylor Glacier", "locations": "Antarctica; Taylor Glacier", "north": -77.7, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "persons": "Menking, James; Shackleton, Sarah; Bauska, Thomas; Buffen, Aron; Brook, Edward J.; Barker, Stephen; Severinghaus, Jeffrey P.; Dyonisius, Michael; Petrenko, Vasilii; Menking, Andy", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.8, "title": "Taylor Glacier CO2 Isotope Data 74-59 kyr", "uid": "601600", "west": 161.0}, {"awards": "1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward J.; 1245659 Petrenko, Vasilii", "bounds_geometry": null, "date_created": "Mon, 28 Dec 2020 00:00:00 GMT", "description": "Inert gas measurements on a large diameter (0.24m), shallow (20m) ice core from Taylor Glacier for mean ocean temperature reconstruction from 60 - 74 ka.\r\nFour samples were also measured on the WAIS Divide ice core to validate Taylor Glacier reconstruction. ", "east": null, "geometry": null, "keywords": "Antarctica; Glaciology; Ice Core Data; Ice Core Records; Paleoclimate; Paleotemperature; Taylor Glacier", "locations": "Taylor Glacier; Antarctica", "north": null, "nsf_funding_programs": null, "persons": "Shackleton, Sarah", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Mean Ocean Temperature in Marine Isotope Stage 4", "uid": "601415", "west": null}, {"awards": "1245821 Brook, Edward J.; 1246148 Severinghaus, Jeffrey; 1245659 Petrenko, Vasilii", "bounds_geometry": null, "date_created": "Mon, 02 Nov 2020 00:00:00 GMT", "description": "Ice core measurements of the concentration and stable isotopic composition of atmospheric nitrous oxide (N2O) 74,000-59,000 years ago constrain marine and terrestrial emissions. The data include two major Dansgaard-Oeschger (D-O) events and the N2O decrease during global cooling at the Marine Isotope Stage (MIS) 5a-4 transition. The N2O increase associated with D-O 19 (~73-71.5 ka) was driven by equal contributions from marine and terrestrial emissions. The N2O decrease during the transition into MIS 4 (~71.5-67.5 ka) was caused by gradual reductions of similar magnitude in both marine and terrestrial sources. A 50 ppb increase in N2O concentration at the end of MIS 4 was caused by gradual increases in marine and terrestrial emissions between ~64-61 ka, followed by an abrupt increase in marine emissions at the onset of D-O 16/17 (59.5 ka). This suggests that the importance of marine versus terrestrial emissions in controlling millennial-scale N2O fluctuations varied in time.", "east": null, "geometry": null, "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Data; Ice Core Gas Records; Ice Core Records; Marine Isotope Stage 4; MIS 4; Nitrous Oxide; Pleistocene; Taylor Dome Ice Core; Taylor Glacier", "locations": "Taylor Glacier; Antarctica; Taylor Glacier", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "persons": "Menking, James; Brook, Edward J.; Schilt, Adrian; Shackleton, Sarah; Dyonisius, Michael; Severinghaus, Jeffrey P.; Petrenko, Vasilii", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Taylor Dome Ice Core", "south": null, "title": "N2O Concentration and Isotope Data for 74-59 ka from Taylor Glacier, Antarctica", "uid": "601398", "west": null}, {"awards": "1245659 Petrenko, Vasilii", "bounds_geometry": ["POINT(161.71353 -77.75855)"], "date_created": "Fri, 28 Feb 2020 00:00:00 GMT", "description": "This data set contains measurements of 14CH4 and 14CO in ice cores from Taylor Glacier, Antarctica. This includes measurements in ice from the last deglaciation (18 - 8 kyr), for the purposes of paleoatmospheric 14CH4 reconstruction. The data set also includes measurements in older ice (50 - 70 kyr) from a deep ice core, made for the purposes of studying in situ cosmogenic 14C production in ice. All data are in excel format.", "east": 161.71353, "geometry": ["POINT(161.71353 -77.75855)"], "keywords": "Antarctica; Carbon-14; Cosmogenic; Ice Core; Methane", "locations": "Antarctica", "north": -77.75855, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Petrenko, Vasilii; Dyonisius, Michael", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Taylor Dome Ice Core", "south": -77.75855, "title": "Measurements of 14CH4 and 14CO in ice from Taylor Glacier: Last Deglaciation and Deep Core Results", "uid": "601260", "west": 161.71353}, {"awards": "1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward J.; 1245659 Petrenko, Vasilii", "bounds_geometry": ["POLYGON((123.3 -75.1,127.138 -75.1,130.976 -75.1,134.814 -75.1,138.652 -75.1,142.49 -75.1,146.328 -75.1,150.166 -75.1,154.004 -75.1,157.842 -75.1,161.68 -75.1,161.68 -75.367,161.68 -75.634,161.68 -75.901,161.68 -76.168,161.68 -76.435,161.68 -76.702,161.68 -76.969,161.68 -77.236,161.68 -77.503,161.68 -77.77,157.842 -77.77,154.004 -77.77,150.166 -77.77,146.328 -77.77,142.49 -77.77,138.652 -77.77,134.814 -77.77,130.976 -77.77,127.138 -77.77,123.3 -77.77,123.3 -77.503,123.3 -77.236,123.3 -76.969,123.3 -76.702,123.3 -76.435,123.3 -76.168,123.3 -75.901,123.3 -75.634,123.3 -75.367,123.3 -75.1))"], "date_created": "Fri, 18 Oct 2019 00:00:00 GMT", "description": "Noble gas data from Taylor Glacier and EPICA Dome C (EDC) for mean ocean temperature reconstruction during the Last Interglacial. Also includes trace gas measurements of d18Oatm, CO2, and CH4 from Taylor Glacier from chronology construction. ", "east": 161.68, "geometry": ["POINT(142.49 -76.435)"], "keywords": "Antarctica; Carbon-14; Carbon Dioxide; Chemistry:ice; Chemistry:Ice; CO2; Dome C Ice Core; Epica; Epica Dome C; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice; Ice Core Chemistry; Ice Core Data; Ice Core Gas Records; Ice Core Records; Isotope Data; Last Interglacial; Mass Spectrometer; Mass Spectrometry; Methane; Oxygen; Oxygen Isotope; Paleotemperature; Pleistocene; Snow/ice; Snow/Ice; Taylor Dome Ice Core; Taylor Glacier", "locations": "Epica Dome C; Antarctica; Taylor Glacier", "north": -75.1, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Shackleton, Sarah", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Taylor Dome Ice Core; Dome C Ice Core", "south": -77.77, "title": "Last Interglacial Mean Ocean Temperature", "uid": "601218", "west": 123.3}, {"awards": "1245659 Petrenko, Vasilii; 1245821 Brook, Edward J.; 1246148 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(162.167 -77.733)"], "date_created": "Mon, 12 Aug 2019 00:00:00 GMT", "description": "New ice cores retrieved from the Taylor Glacier (Antarctica) blue ice area contain ice and air spanning the Marine Isotope Stage (MIS) 5-4 transition, a period of global cooling and ice sheet expansion. We determine chronologies for the ice and air bubbles in the new ice cores by visually matching variations in gas- and ice- phase tracers to preexisting ice core records. The chronologies reveal an ice age-gas age difference (\u0394age) approaching 10 ka during MIS 4, implying very low snow accumulation in the Taylor Glacier accumulation zone. A revised chronology for the analagous section of the Taylor Dome ice core (84 to 55 ka), located to the south of the Taylor Glacier accumulation zone, shows that \u0394age did not exceed 3 ka. The difference in \u0394age between the two records during MIS 4 is similar in magnitude but opposite in direction to what is observed at the Last Glacial Maximum. This relationship implies that a spatial gradient in snow accumulation existed across the Taylor Dome region during MIS 4 that was oriented in the opposite direction of the accumulation gradient during the Last Glacial Maximum.", "east": 162.167, "geometry": ["POINT(162.167 -77.733)"], "keywords": "Antarctica; Blue Ice; Chemistry:ice; Chemistry:Ice; CO2; Dust; Gas; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Mass Spectrometer; Methane; Nitrogen Isotopes; Oxygen Isotope; Paleoclimate; Snow/ice; Snow/Ice; Taylor Dome; Taylor Dome Ice Core", "locations": "Taylor Dome; Antarctica", "north": -77.733, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Glaciology; Antarctic Glaciology", "persons": "Menking, James; Brook, Edward J.; Marcott, Shaun; Barker, Stephen; Shackleton, Sarah; Dyonisius, Michael; Petrenko, Vasilii; McConnell, Joseph; Rhodes, Rachel; Bauska, Thomas; Baggenstos, Daniel; Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.733, "title": "Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores", "uid": "601198", "west": 162.167}, {"awards": "1245821 Brook, Edward J.; 1246148 Severinghaus, Jeffrey; 1245659 Petrenko, Vasilii; 0739766 Brook, Edward J.", "bounds_geometry": ["POLYGON((161.68 -77.73,161.7 -77.73,161.72 -77.73,161.74 -77.73,161.76 -77.73,161.78 -77.73,161.8 -77.73,161.82 -77.73,161.84 -77.73,161.86 -77.73,161.88 -77.73,161.88 -77.734,161.88 -77.738,161.88 -77.742,161.88 -77.746,161.88 -77.75,161.88 -77.754,161.88 -77.758,161.88 -77.762,161.88 -77.766,161.88 -77.77,161.86 -77.77,161.84 -77.77,161.82 -77.77,161.8 -77.77,161.78 -77.77,161.76 -77.77,161.74 -77.77,161.72 -77.77,161.7 -77.77,161.68 -77.77,161.68 -77.766,161.68 -77.762,161.68 -77.758,161.68 -77.754,161.68 -77.75,161.68 -77.746,161.68 -77.742,161.68 -77.738,161.68 -77.734,161.68 -77.73))"], "date_created": "Tue, 23 Apr 2019 00:00:00 GMT", "description": "Noble gas data from Taylor Glacier for mean ocean temperature reconstruction during the Younger Dryas. Also includes field measurements of methane and standard deviations of replicate CO2 measurements from WAIS Divide. ", "east": 161.88, "geometry": ["POINT(161.78 -77.75)"], "keywords": "Antarctica; CO2; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core; Ice Core Records; Methane; Noble Gas; Noble Gas Isotopes; Snow/ice; Snow/Ice; Taylor Glacier; Younger Dryas", "locations": "Taylor Glacier; Antarctica", "north": -77.73, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Shackleton, Sarah", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "Taylor Dome Ice Core", "south": -77.77, "title": "Taylor Glacier Noble Gases - Younger Dryas", "uid": "601176", "west": 161.68}, {"awards": "0839031 Severinghaus, Jeffrey; 1246148 Severinghaus, Jeffrey", "bounds_geometry": ["POLYGON((161.41425 -77.73489,161.486884 -77.73489,161.559518 -77.73489,161.632152 -77.73489,161.704786 -77.73489,161.77742 -77.73489,161.850054 -77.73489,161.922688 -77.73489,161.995322 -77.73489,162.067956 -77.73489,162.14059 -77.73489,162.14059 -77.747868,162.14059 -77.760846,162.14059 -77.773824,162.14059 -77.786802,162.14059 -77.79978,162.14059 -77.812758,162.14059 -77.825736,162.14059 -77.838714,162.14059 -77.851692,162.14059 -77.86467,162.067956 -77.86467,161.995322 -77.86467,161.922688 -77.86467,161.850054 -77.86467,161.77742 -77.86467,161.704786 -77.86467,161.632152 -77.86467,161.559518 -77.86467,161.486884 -77.86467,161.41425 -77.86467,161.41425 -77.851692,161.41425 -77.838714,161.41425 -77.825736,161.41425 -77.812758,161.41425 -77.79978,161.41425 -77.786802,161.41425 -77.773824,161.41425 -77.760846,161.41425 -77.747868,161.41425 -77.73489))"], "date_created": "Fri, 08 Jun 2018 00:00:00 GMT", "description": "This dataset contains the chemistry and dust measurements from Taylor Glacier as well as the new Taylor Dome TD2015 time scale described in Baggenstos et al. (2018). ", "east": 162.14059, "geometry": ["POINT(161.77742 -77.79978)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Horizontal Ice Core; Ice Core Records; Taylor Dome; Taylor Dome Ice Core", "locations": "Taylor Dome; Antarctica", "north": -77.73489, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica", "projects": [{"proj_uid": "p0000099", "repository": "USAP-DC", "title": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.86467, "title": "Taylor Glacier chemistry data and Taylor Dome TD2015 time scale", "uid": "601103", "west": 161.41425}, {"awards": "0839031 Severinghaus, Jeffrey", "bounds_geometry": ["POLYGON((161.41425 -77.73489,161.486884 -77.73489,161.559518 -77.73489,161.632152 -77.73489,161.704786 -77.73489,161.77742 -77.73489,161.850054 -77.73489,161.922688 -77.73489,161.995322 -77.73489,162.067956 -77.73489,162.14059 -77.73489,162.14059 -77.747868,162.14059 -77.760846,162.14059 -77.773824,162.14059 -77.786802,162.14059 -77.79978,162.14059 -77.812758,162.14059 -77.825736,162.14059 -77.838714,162.14059 -77.851692,162.14059 -77.86467,162.067956 -77.86467,161.995322 -77.86467,161.922688 -77.86467,161.850054 -77.86467,161.77742 -77.86467,161.704786 -77.86467,161.632152 -77.86467,161.559518 -77.86467,161.486884 -77.86467,161.41425 -77.86467,161.41425 -77.851692,161.41425 -77.838714,161.41425 -77.825736,161.41425 -77.812758,161.41425 -77.79978,161.41425 -77.786802,161.41425 -77.773824,161.41425 -77.760846,161.41425 -77.747868,161.41425 -77.73489))"], "date_created": "Fri, 16 Jun 2017 00:00:00 GMT", "description": "Taylor Glacier Gas Isotope Data", "east": 162.14059, "geometry": ["POINT(161.77742 -77.79978)"], "keywords": "Antarctica; Chemistry:ice; Chemistry:Ice; Geochemistry; Glaciology; Ice Core Records; Isotope; Solid Earth; Taylor Glacier; Transantarctic Mountains", "locations": "Antarctica; Taylor Glacier; Transantarctic Mountains", "north": -77.73489, "nsf_funding_programs": null, "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica", "projects": [{"proj_uid": "p0000099", "repository": "USAP-DC", "title": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.86467, "title": "Taylor Glacier Gas Isotope Data", "uid": "601033", "west": 161.41425}, {"awards": "1245659 Petrenko, Vasilii", "bounds_geometry": ["POINT(161.71353 -77.75855)"], "date_created": "Wed, 24 May 2017 00:00:00 GMT", "description": "This dataset contains measurements of paleoatmospheric 14C of methane (14CH4) for the Younger Dryas - Preboreal Transition from Taylor Glacier, Antarctica, as well as a range of supporting data. The supporting data include [CH4], [CO], [14CO], sample ages, CH4 emissions and analysis of uncertainties.", "east": 161.71353, "geometry": ["POINT(161.71353 -77.75855)"], "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Critical Zone; Geochemistry; Methane; Paleoclimate; Sample/collection Description; Sample/Collection Description; Solid Earth; Taylor Glacier; Transantarctic Mountains; Younger Dryas", "locations": "Antarctica; Taylor Glacier; Transantarctic Mountains", "north": -77.75855, "nsf_funding_programs": null, "persons": "Petrenko, Vasilii; Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica", "projects": [{"proj_uid": "p0000099", "repository": "USAP-DC", "title": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.75855, "title": "Measurements of 14C-methane for the Younger Dryas - Preboreal Transition from Taylor Glacier, Antarctica", "uid": "601029", "west": 161.71353}, {"awards": "0839031 Severinghaus, Jeffrey", "bounds_geometry": ["POINT(161.71965 -77.76165)"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "This award supports a project to develop a precise gas-based chronology for an archive of large-volume samples of the ancient atmosphere, which would enable ultra-trace gas measurements that are currently precluded by sample size limitations of ice cores. The intellectual merit of the proposed work is that it will provide a critical test of the \u0027clathrate hypothesis\u0027 that methane clathrates contributed to the two abrupt atmospheric methane concentration increases during the last deglaciation 15 and 11 kyr ago. This approach employs large volumes of ice (\u003e1 ton) to measure carbon-14 on past atmospheric methane across the abrupt events. Carbon-14 is an ideal discriminator of fossil sources of methane to the atmosphere, because most methane sources (e.g., wetlands, termites, biomass burning) are rich in carbon-14, whereas clathrates and other fossil sources are devoid of carbon-14. The proposed work is a logical extension to Taylor Glacier, Antarctica, of an approach pioneered at the margin of the Greenland ice sheet over the past 7 years. The Greenland work found higher-than-expected carbon-14 values, likely due in part to contaminants stemming from the high impurity content of Greenland ice and the interaction of the ice with sediments from the glacier bed. The data also pointed to the possibility of a previously unknown process, in-situ cosmogenic production of carbon-14 methane (radiomethane) in the ice matrix. Antarctic ice in Taylor Glacier is orders of magnitude cleaner than the ice at the Greenland site, and is much colder and less stratigraphically disturbed, offering the potential for a clear resolution of this puzzle and a definitive test of the cosmogenic radiomethane hypothesis. Even if cosmogenic radiomethane in ice is found, it still may be possible to reconstruct atmospheric radiomethane with a correction enabled by a detailed understanding of the process, which will be sought by co-measuring carbon-14 in carbon monoxide and carbon dioxide. The broader impacts of the proposed work are that the clathrate test may shed light on the stability of the clathrate reservoir and its potential for climate feedbacks under human-induced warming. Development of Taylor Glacier as a \u0027horizontal ice core\u0027 would provide a community resource for other researchers. Education of one postdoc, one graduate student, and one undergraduate, would add to human resources. This award has field work in Antarctica.", "east": 161.71965, "geometry": ["POINT(161.71965 -77.76165)"], "keywords": "Antarctica; Cosmogenic; Geochemistry; Ice Core Records; Paleoclimate; Radiocarbon; Taylor Glacier; Transantarctic Mountains", "locations": "Taylor Glacier; Transantarctic Mountains; Antarctica", "north": -77.76165, "nsf_funding_programs": null, "persons": "Severinghaus, Jeffrey P.", "project_titles": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica", "projects": [{"proj_uid": "p0000099", "repository": "USAP-DC", "title": "Collaborative Research: A \"Horizontal Ice Core\" for Large-Volume Samples of the Past Atmosphere, Taylor Glacier, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.76165, "title": "Measurements of in situ cosmogenic 14C from Taylor Glacier, Antarctica", "uid": "600165", "west": 161.71965}, {"awards": "1245821 Brook, Edward J.", "bounds_geometry": ["POINT(162.167 -77.733)"], "date_created": "Fri, 01 Jan 2016 00:00:00 GMT", "description": "This award supports a project to use the Taylor Glacier, Antarctica, ablation zone to collect ice samples for a range of paleoenvironmental studies. A record of carbon-14 of atmospheric methane (14CH4) will be obtained for the last deglaciation and the Early Holocene, together with a supporting record of CH4 stable isotopes. In-situ cosmogenic 14C content and partitioning of 14C between different species (14CH4, C-14 carbon monoxide (14CO) and C-14 carbon dioxide (14CO2)) will be determined with unprecedented precision in ice from the surface down to ~67 m. Further age-mapping of the ablating ice stratigraphy will take place using a combination of CH4, CO2, and delta 18O of oxygen gas and H2O stable isotopes. High precision, high-resolution records of CO2, delta 13C of CO2, nitrous oxide (N2O) and N2O isotopes will be obtained for the last deglaciation and intervals during the last glacial period. The potential of 14CO2 and Krypton-81 (81Kr) as absolute dating tools for glacial ice will be investigated. The intellectual merit of proposed work includes the fact that the response of natural methane sources to continuing global warming is uncertain, and available evidence is insufficient to rule out the possibility of catastrophic releases from large 14C-depleted reservoirs such as CH4 clathrates and permafrost. The proposed paleoatmospheric 14CH4 record will improve our understanding of the possible magnitude and timing of CH4 release from these reservoirs during a large climatic warming. A thorough understanding of in-situ cosmogenic 14C in glacial ice (production rates by different mechanisms and partitioning between species) is currently lacking. Such an understanding will likely enable the use of in-situ 14CO in ice at accumulation sites as a reliable, uncomplicated tracer of the past cosmic ray flux and possibly past solar activity, as well as the use of 14CO2 at both ice accumulation and ice ablation sites as an absolute dating tool. Significant gaps remain in our understanding of the natural carbon cycle, as well as in its responses to global climate change. The proposed high-resolution, high-precision records of delta 13C of CO2 would provide new information on carbon cycle changes both during times of rising CO2 in a warming climate and falling CO2 in a cooling climate. N2O is an important greenhouse gas that increased by ~30% during the last deglaciation. The causes of this increase are still largely uncertain, and the proposed high-precision record of N2O concentration and isotopes would provide further insights into N2O source changes in a warming world. The broader impacts of proposed work include an improvement in our understanding of the response of these greenhouse gas budgets to global warming and inform societally important model projections of future climate change. The continued age-mapping of Taylor Glacier ablation ice will add value to this high-quality, easily accessible archive of natural environmental variability. Establishing 14CO as a robust new tracer for past cosmic ray flux would inform paleoclimate studies and constitute a valuable contribution to the study of the societally important issue of climate change. The proposed work will contribute to the development of new laboratory and field analytical systems. The data from the study will be made available to the scientific community and the broad public through the NSIDC and NOAA Paleoclimatology data centers. 1 graduate student each will be trained at UR, OSU and SIO, and the work will contribute to the training of a postdoc at OSU. 3 UR undergraduates will be involved in fieldwork and research. The work will support a new, junior UR faculty member, Petrenko. All PIs have a strong history of and commitment to scientific outreach in the forms of media interviews, participation in filming of field projects, as well as speaking to schools and the public about their research, and will continue these activities as part of the proposed work. This award has field work in Antarctica.", "east": 162.167, "geometry": ["POINT(162.167 -77.733)"], "keywords": "Antarctica; Atmosphere; Geochemistry; Ice Core Records; Isotope; Paleoclimate; Taylor Glacier; Transantarctic Mountains", "locations": "Transantarctic Mountains; Antarctica; Taylor Glacier", "north": -77.733, "nsf_funding_programs": null, "persons": "Brook, Edward J.", "project_titles": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "projects": [{"proj_uid": "p0000283", "repository": "USAP-DC", "title": "Collaborative Research: The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.733, "title": "The Taylor Glacier, Antarctica, Horizontal Ice Core: Exploring changes in the Natural Methane Budget in a Warming World and Expanding the Paleo-archive", "uid": "600163", "west": 162.167}]

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