{"dp_type": "Dataset", "free_text": "Last Glacial Maximum"}
[{"awards": null, "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))"], "date_created": "Fri, 13 Oct 2023 00:00:00 GMT", "description": "This data set contains the VSMOW-SLAP d170, d180, and 170-excess data from the WAIS Divide Ice Core Project, Siple Dome and Taylor Dome, along with the published and VSMOW-SLAP normalized d170, d180, and 170-excess for Vostok [Landais et al.2008], EPICA Dome C and Talos Dome [Wrinkler et al.,2012]. The data cover the Last Glacial Maximum (25-20 ka), through the Early Holocene (12-9 ka) and into present-day (past 2 kyr).", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Delta 18O; Delta O-17; Epica Dome C; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Siple Dome; Talos Dome; Taylor Dome; Vostok", "locations": "Siple Dome; Taylor Dome; Talos Dome; Epica Dome C; Vostok; Antarctica; Siple Dome; Taylor Dome; Epica Dome C; Talos Dome", "north": -60.0, "nsf_funding_programs": null, "persons": "Steig, Eric J.; Schoenemann, Spruce", "project_titles": null, "projects": null, "repositories": null, "science_programs": "WAIS Divide Ice Core", "south": -90.0, "title": "VSMOW-SLAP d170, d180, and 17O-excess data from WAIS Divide Ice Core Project, Siple Dome and Taylor Dome", "uid": "601743", "west": -180.0}, {"awards": "1745078 Brook, Edward J.", "bounds_geometry": ["POINT(-112.05 -79.28)"], "date_created": "Thu, 05 Oct 2023 00:00:00 GMT", "description": "This dataset includes measurements of atmospheric methane from samples from the NEEM, GISP2 and WAIS Divide ice cores. All measurements were made at the Oregon State University Ice Core and Quaternary Geochemistry Laboratory (Corvallis, OR) using an established analytical system. 433 samples from the NEEM ice core were measured between 1420 and 1560m depths. A measurement uncertainty ranging from 2.8 to 4.2 ppb, depending on the measurement year, was determined from replicate samples. 340 samples from the GISP2 ice core were measured between 1740 and 2060m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. All GISP2 and NEEM data were corrected for excess methane contamination using the established relationship between excess methane and Ca2+ (Lee et al., 2020). Both corrected and uncorrected data are included in the publication. 340 samples from the GISP2 ice core were measured between 1957 and 3081m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. Depths reflect the mid-points of the depth range of each samples, which is typically ~8cm. All replicate measurements are included in the dataset.\r\n\r\nLee, J. E. et al. Excess methane in Greenland ice cores associated with high dust concentrations. Geochimica et cosmochimica acta 270, 409-430 (2020).", "east": -112.05, "geometry": ["POINT(-112.05 -79.28)"], "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Greenland; Ice Core Records; Methane; West Antarctic Ice Sheet", "locations": "West Antarctic Ice Sheet; Antarctica; Greenland", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Riddell-Young, Benjamin; Martin, Kaden; Rosen, Julia; Lee, James; Edwards, Jon S.; Brook, Edward J.", "project_titles": "Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores", "projects": [{"proj_uid": "p0010416", "repository": "USAP-DC", "title": "Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -79.28, "title": "Atmospheric methane across the Last Glacial Maximum and deglaciation from the GISP2, NEEM and WAIS Divide ice cores ", "uid": "601737", "west": -112.05}, {"awards": "1745078 Brook, Edward J.", "bounds_geometry": ["POINT(-112.05 -79.28)"], "date_created": "Mon, 02 Oct 2023 00:00:00 GMT", "description": "This dataset includes estimates of the atmospheric methane relative interpolar difference (rIPD) across the Last Glacial Maximum and Deglaciation. The rIPD was calculated using discrete, high-resolution methane measurements from the WAIS Divide, NEEM and GISP2 ice cores. Two independent IPD records were determined: One using NEEM and WAIS and one using GISP2 and WAIS. The dataset includes rIPD values calculated using both Greenland methane data both corrected and uncorrected for excess methane (Lee et al., 2020). The rIPD was calculated by smoothing each methane record and synchronizing them to the WD2014 gas age scale. 1-sigma rIPD uncertainties are included. This dataset also includes the output of the four-box troposphere model used to interpret the rIPD. For both excess methane-corrected records, the model output and 1-sigma uncertainty is provided for northern extratropical (30N - 90N) and total tropical (30S - 30N) sources in Tg yr-1. For the NEEM-derived rIPD, sections of the rIPD where atmospheric methane changed rapidly were deemed untrustworthy were removed from the dataset.\r\n\r\nLee, J. E. et al. Excess methane in Greenland ice cores associated with high dust concentrations. Geochimica et cosmochimica acta 270, 409-430 (2020).", "east": -112.05, "geometry": ["POINT(-112.05 -79.28)"], "keywords": "Antarctica; Greenland; Methane; Paleoclimate; West Antarctic Ice Sheet", "locations": "Greenland; West Antarctic Ice Sheet; Antarctica", "north": -79.28, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Riddell-Young, Benjamin; Rosen, Julia; Buizert, Christo; Martin, Kaden; Lee, James; Edwards, Jon S.; M\u00fchl, Michaela; Schmitt, Jochen; Fischer, Hubertus; Blunier, Thomas; Brook, Edward J.", "project_titles": "Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores", "projects": [{"proj_uid": "p0010416", "repository": "USAP-DC", "title": "Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -79.28, "title": "Atmospheric methane interpolar difference and four-box troposphere model output across the Last Glacial Maximum and Deglaciation", "uid": "601736", "west": -112.05}, {"awards": "0944150 Hall, Brenda", "bounds_geometry": ["POLYGON((163.7 -77.9,163.79 -77.9,163.88 -77.9,163.97 -77.9,164.06 -77.9,164.15 -77.9,164.24 -77.9,164.33 -77.9,164.42 -77.9,164.51 -77.9,164.6 -77.9,164.6 -77.91,164.6 -77.92,164.6 -77.93,164.6 -77.94,164.6 -77.95,164.6 -77.96,164.6 -77.97,164.6 -77.98,164.6 -77.99,164.6 -78,164.51 -78,164.42 -78,164.33 -78,164.24 -78,164.15 -78,164.06 -78,163.97 -78,163.88 -78,163.79 -78,163.7 -78,163.7 -77.99,163.7 -77.98,163.7 -77.97,163.7 -77.96,163.7 -77.95,163.7 -77.94,163.7 -77.93,163.7 -77.92,163.7 -77.91,163.7 -77.9))"], "date_created": "Wed, 20 Apr 2022 00:00:00 GMT", "description": "This dataset includes radiocarbon dates of benthic algal mats associated with last glacial maximum Ross Sea drift in Salmon Valley, Royal Society Range.", "east": 164.6, "geometry": ["POINT(164.15 -77.95)"], "keywords": "Antarctica; Last Glacial Maximum; McMurdo Sound; Radiocarbon Dates; Ross Sea Drift; Royal Society Range", "locations": "Royal Society Range; Ross Sea Drift; McMurdo Sound; Antarctica", "north": -77.9, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hall, Brenda", "project_titles": "Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles", "projects": [{"proj_uid": "p0010302", "repository": "USAP-DC", "title": "Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Salmon Valley Radiocarbon Data", "uid": "601556", "west": 163.7}, {"awards": "0944150 Hall, Brenda", "bounds_geometry": ["POLYGON((163.5 -77.3,163.65 -77.3,163.8 -77.3,163.95 -77.3,164.1 -77.3,164.25 -77.3,164.4 -77.3,164.55 -77.3,164.7 -77.3,164.85 -77.3,165 -77.3,165 -77.39,165 -77.48,165 -77.57,165 -77.66,165 -77.75,165 -77.84,165 -77.93,165 -78.02,165 -78.11,165 -78.2,164.85 -78.2,164.7 -78.2,164.55 -78.2,164.4 -78.2,164.25 -78.2,164.1 -78.2,163.95 -78.2,163.8 -78.2,163.65 -78.2,163.5 -78.2,163.5 -78.11,163.5 -78.02,163.5 -77.93,163.5 -77.84,163.5 -77.75,163.5 -77.66,163.5 -77.57,163.5 -77.48,163.5 -77.39,163.5 -77.3))"], "date_created": "Wed, 20 Apr 2022 00:00:00 GMT", "description": "This dataset contains radiocarbon dates of benthic algal (cyanobacterial) mats within moraines associated with Ross Sea drift on the headlands of the Royal Society Range and covers the time period ~12-20 ka.", "east": 165.0, "geometry": ["POINT(164.25 -77.75)"], "keywords": "Antarctica; Last Glacial Maximum; McMurdo Sound; Radiocarbon Dates; Ross Sea Drift; Royal Society Range", "locations": "Royal Society Range; Royal Society Range; Antarctica; McMurdo Sound; Ross Sea Drift", "north": -77.3, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Hall, Brenda", "project_titles": "Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles", "projects": [{"proj_uid": "p0010302", "repository": "USAP-DC", "title": "Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.2, "title": "Royal Society Range Headland Moraine Belt Radiocarbon Data", "uid": "601555", "west": 163.5}, {"awards": "1643248 Hall, Brenda; 0944150 Hall, Brenda", "bounds_geometry": ["POLYGON((164 -78,164.04 -78,164.08 -78,164.12 -78,164.16 -78,164.2 -78,164.24 -78,164.28 -78,164.32 -78,164.36 -78,164.4 -78,164.4 -78.01,164.4 -78.02,164.4 -78.03,164.4 -78.04,164.4 -78.05,164.4 -78.06,164.4 -78.07,164.4 -78.08,164.4 -78.09,164.4 -78.1,164.36 -78.1,164.32 -78.1,164.28 -78.1,164.24 -78.1,164.2 -78.1,164.16 -78.1,164.12 -78.1,164.08 -78.1,164.04 -78.1,164 -78.1,164 -78.09,164 -78.08,164 -78.07,164 -78.06,164 -78.05,164 -78.04,164 -78.03,164 -78.02,164 -78.01,164 -78))"], "date_created": "Tue, 01 Mar 2022 00:00:00 GMT", "description": "This dataset includes 234U/230Th chronologic data for lacustrine carbonates associated with Marshall drift in Marshall Valley, Royal Society Range. These samples are from ice-dammed lake deposits associated with a grounded ice sheet that blocked the valley mouth. Sample chemistry was done at the University of Maine geochemistry laboratory. Processed samples were analyzed on a multicollector ICP-MS at the University of Oxford. Corrected ages reflect a detrital correction based on typical upper-crustal (230Th/232Th) values of 1.21 with a 50% assumed error.", "east": 164.4, "geometry": ["POINT(164.2 -78.05)"], "keywords": "234U/230Th Dating; Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Last Glacial Maximum; Marshall Drift; Marshall Valley; MIS 6; Royal Society Range", "locations": "Marshall Valley; Royal Society Range; Antarctica", "north": -78.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology", "persons": "Hall, Brenda", "project_titles": "Response of the Antarctic Ice Sheet to the last great global warming; Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles", "projects": [{"proj_uid": "p0010301", "repository": "USAP-DC", "title": "Response of the Antarctic Ice Sheet to the last great global warming"}, {"proj_uid": "p0010302", "repository": "USAP-DC", "title": "Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.1, "title": "Marshall Valley U-Series Data", "uid": "601528", "west": 164.0}, {"awards": "1246353 Anderson, John; 1745043 Simkins, Lauren; 1745055 Stearns, Leigh", "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))"], "date_created": "Wed, 10 Nov 2021 00:00:00 GMT", "description": "The dataset here allows exploration of the causes and significance of Antarctic grounding-line sinuosity by coupling observations of contemporary Antarctic grounding lines and paleo-grounding lines expressed as ice-marginal landforms on the Ross Sea continental shelf. Modern grounding lines are derived from the MEaSUREs Version 2 Differential Satellite Radar Interferometry dataset with spatial resolutions of 25-120 m spanning February 1992 to December 2014 (Rignot et al., 2016; Mouginot et al., 2017). The boundaries of individual grounding lines representative of individual glacial catchments (n=664) were delineated by the inflection points of the shear strain rate, \u03b5xy (c.f Van der Veen et al., 2011). Sinuosity was calculated as the ratio of the true length, orthogonal to ice-flow direction, of the grounding lines and the straight line length between end-points and in units of km/km. Raster data were extracted at 1-km points along each grounding line; the mean was calculated for each grounding line and merged in a table with sinuosity data. A dataset of 6,275 paleo-grounding lines expressed as ice-marginal landforms on the deglaciated western Ross Sea continental shelf are used in this study, originally published by Simkins et al., 2018. The ice-marginal landforms were mapped from multibeam echo sounder data that was collected onboard the RVIB Nathaniel B. Palmer (NBP) 15-02 cruise using a Kongsberg EM122 operating in dual swath mode at 12 kHz frequency with 30-60% swath overlap (Cruise DOI: 10.7284/901477). The resulting bathymetry data was gridded at 20-40 m with decimeter vertical elevation resolution depending on water depth and sea-state. Sinuosity is calculated as a ratio of true (mapped) landform length, measured in the across paleo-ice flow direction at the crest of the landform, to the straight line distance between the mapped landform endpoints and in units of km/km. \r\n\r\nTo compare modern and paleo-grounding lines, we use a consistent length scale by segmenting the grounding lines into 2-km sections for the two datasets (modern, n=12,966; paleo, n=5,832), even though this eliminates grounding lines that are less than 2-km long and thus results in 1 modern and 3,873 paleo-grounding lines removed. The full-length and 2-km segmented groundings lines are provided as shapefiles \"InSAR_groundinglines_full\" and \"InSAR_groundinglines_2km\", the paleo-grounding lines are provided as shapefiles \"RossSea_icemarginal_full\" and \"RossSea_icemarginal_2km\", and points marking modern grounding lines retreat from repeat InSAR surveys are provided as shapefile \"InSAR_retreat_points\", all stored together in a geodatabase named \"Antarctic_groundinglines.gbd\". Additional grounding line metrics, including length, sinuosity, bed roughness, and bed slope for modern and paleo-grounding lines, and height-above-buoyancy gradient, ice-flow velocity, presence of pinning points and ice shelves are provided for modern grounding lines. \r\n\r\nThe published dataset was compiled and analyzed in the article \"Controls on circum-Antarctic grounding-line sinuosity \" by Simkins, L.M., Stearns, L.A., and Riverman, K.L, which will be submitted to a peer-review journal in November 2021.\r\n\r\nReferences\r\nMouginot, J., B. Scheuchl, and E. Rignot. 2017. MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. \r\n\r\nRignot, E., J. Mouginot, and B. Scheuchl. 2016. MEaSUREs Antarctic Grounding Line from Differential Satellite Radar Interferometry, Version 2. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. \r\n\r\nSimkins, L. M., Greenwood, S. L., \u0026 Anderson, J. B. (2018). Diagnosing ice sheet grounding line stability from landform morphology. The Cryosphere, 12(8), 2707-2726.\r\n\r\nVan der Veen, C. J., J. C. Plummer, \u0026 L. A. Stearns. (2011). Controls on the recent speed up of Jakobshavn Isbr\u00e6, West Greenland. Journal of Glaciology, 57(204), 770-782", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Bed Roughness; Bed Slope; Elevation; Glaciers/ice Sheet; Glaciers/Ice Sheet; Pinning Points", "locations": "Antarctica; Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "persons": "Simkins, Lauren; Stearns, Leigh; Riverman, Kiya", "project_titles": "Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations; Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum.", "projects": [{"proj_uid": "p0010269", "repository": "USAP-DC", "title": "Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations"}, {"proj_uid": "p0000395", "repository": "USAP-DC", "title": "Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum."}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Circum-Antarctic grounding-line sinuosity", "uid": "601484", "west": -180.0}, {"awards": "1246353 Anderson, John; 1745043 Simkins, Lauren; 1745055 Stearns, Leigh", "bounds_geometry": ["POLYGON((174 -75,174.4 -75,174.8 -75,175.2 -75,175.6 -75,176 -75,176.4 -75,176.8 -75,177.2 -75,177.6 -75,178 -75,178 -75.2,178 -75.4,178 -75.6,178 -75.8,178 -76,178 -76.2,178 -76.4,178 -76.6,178 -76.8,178 -77,177.6 -77,177.2 -77,176.8 -77,176.4 -77,176 -77,175.6 -77,175.2 -77,174.8 -77,174.4 -77,174 -77,174 -76.8,174 -76.6,174 -76.4,174 -76.2,174 -76,174 -75.8,174 -75.6,174 -75.4,174 -75.2,174 -75))"], "date_created": "Mon, 04 Oct 2021 00:00:00 GMT", "description": "Bathymetry from multibeam echo sounding data in Pennell Trough, Ross Sea, Antarctica was collected onboard the RVIB Nathaniel B. Palmer (NBP) 15-02 cruise using a Kongsberg EM122 operating in dual swath mode at 12 kHz frequency with a 1\u00b0\u00d71\u00b0 beam width, swath angular coverage set to 62\u00b0\u00d762\u00b0, and 30-60% overlap between survey lines. All raw, ping-edited geophysical data collected on NBP15-02 can be accessed using the Marine Geoscience Data System (Cruise DOI: 10.7284/901477). The bathymetry dataset here is gridded at 20-m resolution with a water depth-dependent vertical resolution on the order of decimeters. Two shapefiles are provided for ice-marginal landforms and meltwater landforms observable in the bathymetry data. The purpose of collecting the bathymetry data on cruise NBP15-02 was to better understand the glacial history of the Ross Sea, and the dataset, inclusive of bathymetry data and shapefiles of glacial landforms, from Pennell Trough are used to understand impacts on subglacial channel morphology and organization during the deglaciation of the region following the Last Glacial Maximum. The published dataset was used and analyzed in the article \"Topographic controls on channelized meltwater in the subglacial environment\" by Simkins, L.M., Greenwood, S.L., Munevar Garcia, S., Eareckson, E.A., Anderson, J.B., and Prothro, L.O, which was published in Geophysical Research Letters in 2021 (DOI: 10.1029/2021GL094678).", "east": 178.0, "geometry": ["POINT(176 -76)"], "keywords": "Antarctica; Bathymetry; Elevation; Geomorphology; Glacial History; Glaciers/ice Sheet; Glaciers/Ice Sheet; Marine Geoscience; NBP1502; Pennell Trough; Ross Sea; R/v Nathaniel B. Palmer", "locations": "Ross Sea; Pennell Trough; Antarctica", "north": -75.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "persons": "Greenwood, Sarah; Munevar Garcia, Santiago; Eareckson, Elizabeth; Anderson, John; Prothro, Lindsay; Simkins, Lauren", "project_titles": "Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations; Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum.", "projects": [{"proj_uid": "p0000395", "repository": "USAP-DC", "title": "Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum."}, {"proj_uid": "p0010269", "repository": "USAP-DC", "title": "Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.0, "title": "Pennell Trough, Ross Sea bathymetry and glacial landforms", "uid": "601474", "west": 174.0}, {"awards": "1043092 Steig, Eric", "bounds_geometry": ["POLYGON((-158.72 -77.79,-154.056 -77.79,-149.392 -77.79,-144.728 -77.79,-140.064 -77.79,-135.4 -77.79,-130.736 -77.79,-126.072 -77.79,-121.408 -77.79,-116.744 -77.79,-112.08 -77.79,-112.08 -78.178,-112.08 -78.566,-112.08 -78.954,-112.08 -79.342,-112.08 -79.73,-112.08 -80.118,-112.08 -80.506,-112.08 -80.894,-112.08 -81.282,-112.08 -81.67,-116.744 -81.67,-121.408 -81.67,-126.072 -81.67,-130.736 -81.67,-135.4 -81.67,-140.064 -81.67,-144.728 -81.67,-149.392 -81.67,-154.056 -81.67,-158.72 -81.67,-158.72 -81.282,-158.72 -80.894,-158.72 -80.506,-158.72 -80.118,-158.72 -79.73,-158.72 -79.342,-158.72 -78.954,-158.72 -78.566,-158.72 -78.178,-158.72 -77.79))"], "date_created": "Tue, 22 Dec 2020 00:00:00 GMT", "description": "This data set contains the VSMOW-SLAP d17O, d18O, and 17O-excess data from the WAIS Divide Ice Core Project, Siple Dome and Taylor Dome, along with the published and VSMOW-SLAP normalized d17O, d18O, and 17O-excess for Vostok [Landais et al. 2008], EPICA Dome C and Talos Dome [Winkler et al., 2012]. The data cover the Last Glacial Maximum (25-20 ka), through the Early Holocene (12-9 ka) and into present-day (past 2 kyr)", "east": -112.08, "geometry": ["POINT(-135.4 -79.73)"], "keywords": "Antarctica; Ice Core; Oxygen Isotope; WAIS Divide", "locations": "WAIS Divide; Antarctica", "north": -77.79, "nsf_funding_programs": null, "persons": "Steig, Eric J.; Schoenemann, Spruce", "project_titles": "Collaborative Research: Stable Isotopes of Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core", "projects": [{"proj_uid": "p0000010", "repository": "USAP-DC", "title": "Collaborative Research: Stable Isotopes of Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -81.67, "title": "17O excess from WAIS Divide, 0 to 25 ka BP", "uid": "601413", "west": -158.72}, {"awards": "1246148 Severinghaus, Jeffrey; 1245821 Brook, Edward J.; 1245659 Petrenko, Vasilii", "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": "Antarctica; Taylor Dome", "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": "1246353 Anderson, John", "bounds_geometry": ["POLYGON((-180 -74.37,-178.85 -74.37,-177.7 -74.37,-176.55 -74.37,-175.4 -74.37,-174.25 -74.37,-173.1 -74.37,-171.95 -74.37,-170.8 -74.37,-169.65 -74.37,-168.5 -74.37,-168.5 -74.747,-168.5 -75.124,-168.5 -75.501,-168.5 -75.878,-168.5 -76.255,-168.5 -76.632,-168.5 -77.009,-168.5 -77.386,-168.5 -77.763,-168.5 -78.14,-169.65 -78.14,-170.8 -78.14,-171.95 -78.14,-173.1 -78.14,-174.25 -78.14,-175.4 -78.14,-176.55 -78.14,-177.7 -78.14,-178.85 -78.14,180 -78.14,178.48 -78.14,176.96 -78.14,175.44 -78.14,173.92 -78.14,172.4 -78.14,170.88 -78.14,169.36 -78.14,167.84 -78.14,166.32 -78.14,164.8 -78.14,164.8 -77.763,164.8 -77.386,164.8 -77.009,164.8 -76.632,164.8 -76.255,164.8 -75.878,164.8 -75.501,164.8 -75.124,164.8 -74.747,164.8 -74.37,166.32 -74.37,167.84 -74.37,169.36 -74.37,170.88 -74.37,172.4 -74.37,173.92 -74.37,175.44 -74.37,176.96 -74.37,178.48 -74.37,-180 -74.37))"], "date_created": "Mon, 05 Feb 2018 00:00:00 GMT", "description": "Dataset includes details of cores collected as part of cruise NBP1502A, a list of radiocarbon-dated samples and samples to be radiocarbon-dated, and grain-size data from select NBP1502A cores.", "east": -168.5, "geometry": ["POINT(178.15 -76.255)"], "keywords": "Antarctica; Chemistry:sediment; Chemistry:Sediment; Geochronology; Marine Geoscience; Marine Sediments; NBP1502; R/v Nathaniel B. Palmer; Sediment Core", "locations": "Antarctica", "north": -74.37, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Simkins, Lauren; Anderson, John; Prothro, Lindsay", "project_titles": "Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum.", "projects": [{"proj_uid": "p0000395", "repository": "USAP-DC", "title": "Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum."}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.14, "title": "NBP1502A Cruise Core Data", "uid": "601083", "west": 164.8}, {"awards": "0839075 Priscu, John", "bounds_geometry": ["POINT(-112 -79)"], "date_created": "Tue, 12 Dec 2017 00:00:00 GMT", "description": "This data set includes raw concentration of prokaryotic cells for the WAIS Divide deep core, WDC06A, from 1,764 m to 2,709 m. Data were collected by a method that combines acquisition of discrete samples using a continuous ice-core melting system (McConnell et al., 2002) coupled with flow cytometry of DNA-stained samples. The method is described in detail in Santibanez et al., 2016. \r\r\nWe present the first long-term, highly resolved prokaryotic cell concentration record obtained from a polar ice core. This record, obtained from the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core, spanned from the Last Glacial Maximum (LGM) to the early Holocene (EH) and showed distinct fluctuations in prokaryotic cell concentration coincident with major climatic states. This record provided strong evidence that airborne prokaryotic cell deposition differed during the LGM, LDG and EH, and that these changes in cell densities could be explained by different environmental conditions during each of these climatic periods. Our observations provide the first ice core time-series evidence for a prokaryotic response to long-term climatic and environmental processes.", "east": -112.0, "geometry": ["POINT(-112 -79)"], "keywords": "Antarctica; Biota; Cell Counts; Glaciology; Microbiology; WAIS Divide; WAIS Divide Ice Core", "locations": "Antarctica; WAIS Divide", "north": -79.0, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Santibanez, Pamela; Priscu, John", "project_titles": "Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core", "projects": [{"proj_uid": "p0000273", "repository": "USAP-DC", "title": "Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.0, "title": "Prokaryotic cell concentration record from the WAIS Divide ice core", "uid": "601072", "west": -112.0}, {"awards": "0944197 Waddington, Edwin", "bounds_geometry": ["POINT(-112.1115 -79.481)"], "date_created": "Tue, 28 Mar 2017 00:00:00 GMT", "description": "The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ~68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8-31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WD gas age-ice age difference (Delta age) using a combination of firn densification modeling, ice-flow modeling, and a data set of d15N-N2, a proxy for past firn column thickness. The largest Delta age at WD occurs during the Last Glacial Maximum, and is 525 +/- 120 years. Internally consistent solutions can be found only when assuming little to no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WD chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard-Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu Cave speleothem record. The small Delta age at WD provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the \\\"bipolar seesaw\\\".\n\nWe present the WD2014 chronology for the upper part (0-2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5% of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1% of the age at three abrupt climate change events between 27 and 31ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11.595 ka; 24 years younger) and the Bolling-Allerod Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations.", "east": -112.1115, "geometry": ["POINT(-112.1115 -79.481)"], "keywords": "Antarctica; Depth-Age-Model; Geochronology; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.481, "nsf_funding_programs": null, "persons": "Fudge, T. J.", "project_titles": "Collaborative Research: Establishing the Chronology and Histories of Accumulation and Ice Dynamics for the WAIS Divide Core", "projects": [{"proj_uid": "p0000026", "repository": "USAP-DC", "title": "Collaborative Research: Establishing the Chronology and Histories of Accumulation and Ice Dynamics for the WAIS Divide Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.481, "title": "WD2014: Timescale for WAIS Divide Core 2006 A (WDC-06A)", "uid": "601015", "west": -112.1115}, {"awards": "0839075 Priscu, John", "bounds_geometry": ["POINT(-112.08648 -79.46763)"], "date_created": "Mon, 06 Mar 2017 00:00:00 GMT", "description": "This data set include depth (WDC06A-7 dating) and fluorescence intensity measurements for five fluorophore regions (A, C, M, B, and T) commonly found in natural organic matter. Data from 1300-1700m, 1700-2100m, and 2100-2700m correspond to the early Holocene, deglaciation period, and the Last Glacial Maximum.", "east": -112.08648, "geometry": ["POINT(-112.08648 -79.46763)"], "keywords": "Antarctica; Fluorescence Spectroscopy; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Physical Properties; WAIS Divide; WAIS Divide Ice Core", "locations": "WAIS Divide; Antarctica", "north": -79.46763, "nsf_funding_programs": null, "persons": "Priscu, John; D\u0027Andrilli, Juliana", "project_titles": "Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core", "projects": [{"proj_uid": "p0000273", "repository": "USAP-DC", "title": "Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "WAIS Divide Ice Core", "south": -79.46763, "title": "Fluorescence spectroscopy data from the West Antarctic Ice Sheet (WAIS) Divide ice core, WDC06A", "uid": "601006", "west": -112.08648}, {"awards": "1043485 Curtice, Josh", "bounds_geometry": ["POLYGON((163.4 -77.47989,163.9848 -77.47989,164.5696 -77.47989,165.1544 -77.47989,165.7392 -77.47989,166.324 -77.47989,166.9088 -77.47989,167.4936 -77.47989,168.0784 -77.47989,168.6632 -77.47989,169.248 -77.47989,169.248 -77.565701,169.248 -77.651512,169.248 -77.737323,169.248 -77.823134,169.248 -77.908945,169.248 -77.994756,169.248 -78.080567,169.248 -78.166378,169.248 -78.252189,169.248 -78.338,168.6632 -78.338,168.0784 -78.338,167.4936 -78.338,166.9088 -78.338,166.324 -78.338,165.7392 -78.338,165.1544 -78.338,164.5696 -78.338,163.9848 -78.338,163.4 -78.338,163.4 -78.252189,163.4 -78.166378,163.4 -78.080567,163.4 -77.994756,163.4 -77.908945,163.4 -77.823134,163.4 -77.737323,163.4 -77.651512,163.4 -77.565701,163.4 -77.47989))"], "date_created": "Thu, 01 Jan 2015 00:00:00 GMT", "description": "This award supports a project to develop a better understanding of the response of the WAIS to climate change. The timing of the last deglaciation of the western Ross Sea will be improved using in situ terrestrial cosmogenic nuclides (3He, 10Be, 14C, 26Al, 36Cl) to date glacial erratics at key areas and elevations along the western Ross Sea coast. A state-of-the art ice sheet-shelf model will be used to identify mechanisms of deglaciation of the Ross Sea sector of WAIS. The model results and forcing will be compared with observations including the new cosmogenic data proposed here, with the aim of better determining and understanding the history and causes of WAIS deglaciation in the Ross Sea. There is considerable uncertainty, however, in the history of grounding line retreat from its last glacial maximum position, and virtually nothing is known about the timing of ice- surface lowering prior to ~10,000 years ago. Given these uncertainties, we are currently unable to assess one of the most important questions regarding the last deglaciation of the global ice sheets, namely as to whether the Ross Sea sector of WAIS contributed significantly to meltwater pulse 1A (MWP-1A), an extraordinarily rapid (~500-year duration) episode of ~20 m sea-level rise that occurred ~14,500 years ago. The intellectual merit of this project is that recent observations of startling changes at the margins of the Greenland and Antarctic ice sheets indicate that dynamic responses to warming may play a much greater role in the future mass balance of ice sheets than considered in current numerical projections of sea level rise. The broader impacts of this work are that it has direct societal relevance to developing an improved understanding of the response of the West Antarctic ice sheet to current and possible future environmental changes including the sea-level response to glacier and ice sheet melting due to global warming. The PI will communicate results from this project to a variety of audiences through the publication of peer-reviewed papers and by giving talks to public audiences. Finally the project will support a graduate student and undergraduate students in all phases of field-work, laboratory work and data interpretation.\n", "east": 169.248, "geometry": ["POINT(166.324 -77.908945)"], "keywords": "Antarctica; Cosmogenic Dating; Ross Sea; Sample/collection Description; Sample/Collection Description; Southern Ocean; WAIS", "locations": "WAIS; Antarctica; Southern Ocean; Ross Sea", "north": -77.47989, "nsf_funding_programs": null, "persons": "Kurz, Mark D.; Curtice, Josh", "project_titles": "Collaborative Research: A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea", "projects": [{"proj_uid": "p0000194", "repository": "USAP-DC", "title": "Collaborative Research: A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.338, "title": "A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea", "uid": "600123", "west": 163.4}, {"awards": "1043619 Hemming, Sidney", "bounds_geometry": ["POLYGON((-180 -63.997,-179.7982 -63.997,-179.5964 -63.997,-179.3946 -63.997,-179.1928 -63.997,-178.991 -63.997,-178.7892 -63.997,-178.5874 -63.997,-178.3856 -63.997,-178.1838 -63.997,-177.982 -63.997,-177.982 -66.3324,-177.982 -68.6678,-177.982 -71.0032,-177.982 -73.3386,-177.982 -75.674,-177.982 -78.0094,-177.982 -80.3448,-177.982 -82.6802,-177.982 -85.0156,-177.982 -87.351,-178.1838 -87.351,-178.3856 -87.351,-178.5874 -87.351,-178.7892 -87.351,-178.991 -87.351,-179.1928 -87.351,-179.3946 -87.351,-179.5964 -87.351,-179.7982 -87.351,180 -87.351,172.54273 -87.351,165.08546 -87.351,157.62819 -87.351,150.17092 -87.351,142.71365 -87.351,135.25638 -87.351,127.79911 -87.351,120.34184 -87.351,112.88457 -87.351,105.4273 -87.351,105.4273 -85.0156,105.4273 -82.6802,105.4273 -80.3448,105.4273 -78.0094,105.4273 -75.674,105.4273 -73.3386,105.4273 -71.0032,105.4273 -68.6678,105.4273 -66.3324,105.4273 -63.997,112.88457 -63.997,120.34184 -63.997,127.79911 -63.997,135.25638 -63.997,142.71365 -63.997,150.17092 -63.997,157.62819 -63.997,165.08546 -63.997,172.54273 -63.997,-180 -63.997))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Intellectual Merit: The PIs proposed a provenance study of glacial deposits in the Ross Embayment that will provide a broad scale geochronologic survey of detrital minerals in till to help characterize bedrock beneath the East Antarctic ice sheet and constrain Antarctica?s glacial history. This project capitalizes on previous investments in field sampling. Analytical tools applied to single mineral grains extracted from existing collections of glacial till will generate ?fingerprints? of East Antarctic outlet glaciers and West Antarctic till to refine paleo-ice flow models for the Ross Embayment during the last glacial maximum, older records from ANDRILL cores, and to assess IRD sources in the Southern Ocean. New provenance tracers will include a suite of geochronological methods that together provide greater insights into the orogenic and erosional history the region. This project will include U/Pb of detrital zircons, (U-Th)/He on a subset of the U/Pb dated zircons, as well as Ar-Ar of detrital hornblende, mica and feldspars.\nBroader Impacts: This research will train one M.S. student at IUPUI, a Ph.D. student at Columbia, and several undergraduates at both institutions. Graduate students involved in the project will be involved in mentoring undergraduate researchers. Incorporation of research discoveries will be brought into the classroom by providing concrete examples and exercises at the appropriate level. Licht and Columbia graduate student E. Pierce are developing outreach projects with local secondary school teachers to investigate the provenance of glacial materials in their local areas. The research will have broad applicability to many fields.", "east": 105.4273, "geometry": ["POINT(143.72265 -75.674)"], "keywords": "Antarctica; East Antarctica; Geochemistry; Ross Sea; Sample/collection Description; Sample/Collection Description; Solid Earth; Southern Ocean; West Antarctica", "locations": "West Antarctica; Southern Ocean; Ross Sea; Antarctica; East Antarctica", "north": -63.997, "nsf_funding_programs": null, "persons": "Hemming, Sidney R.", "project_titles": "Collaborative Research: East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains", "projects": [{"proj_uid": "p0000333", "repository": "USAP-DC", "title": "Collaborative Research: East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -87.351, "title": "East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains", "uid": "600124", "west": -177.982}, {"awards": "0944474 Robinson, Laura", "bounds_geometry": ["POLYGON((-70.5 -54.5,-66.95 -54.5,-63.4 -54.5,-59.85 -54.5,-56.3 -54.5,-52.75 -54.5,-49.2 -54.5,-45.65 -54.5,-42.1 -54.5,-38.55 -54.5,-35 -54.5,-35 -55.2,-35 -55.9,-35 -56.6,-35 -57.3,-35 -58,-35 -58.7,-35 -59.4,-35 -60.1,-35 -60.8,-35 -61.5,-38.55 -61.5,-42.1 -61.5,-45.65 -61.5,-49.2 -61.5,-52.75 -61.5,-56.3 -61.5,-59.85 -61.5,-63.4 -61.5,-66.95 -61.5,-70.5 -61.5,-70.5 -60.8,-70.5 -60.1,-70.5 -59.4,-70.5 -58.7,-70.5 -58,-70.5 -57.3,-70.5 -56.6,-70.5 -55.9,-70.5 -55.2,-70.5 -54.5))"], "date_created": "Sat, 01 Jan 2011 00:00:00 GMT", "description": "Polar oceans are the main sites of deep-water formation and are critical to the exchange of heat and carbon between the deep ocean and the atmosphere. This award \"Historic perspectives on climate and biogeography from deep-sea corals in the Drake Passage\" will address the following specific research questions: What was the radiocarbon content of the Southern Ocean during the last glacial maximum and during past rapid climate change events? and What are the major controls on the past and present distribution of cold-water corals within the Drake Passage and adjacent continental shelves? Testing these overall questions will allow the researchers to better understand how processes in the Southern Ocean are linked to climate change over millennia. This award is being funded by the Antarctic Earth Sciences Program of NSF\u0027s Office of Polar Programs, Antarctic Division. INTELLECTUAL MERIT: The skeletons of deep-sea corals are abundant in the Southern Ocean, and can be dated using U-series techniques making them a useful archive of oceanographic history. By pairing U-series and radiocarbon analyses the awardees can reconstruct the radiocarbon content of seawater in the past, allowing them to address the research questions raised above. Collection of living deep-sea corals along with environmental data will allow them to address the broader biogeography questions posed above as well. The awardees are uniquely qualified to answer these questions in their respective labs via cutting edge technologies, and they have shown promising results from a preliminary pilot cruise to the area in 2008. BROADER IMPACTS: Societal Relevance: The proposed paleoclimate research will make significant advances toward constraining the Southern Ocean\u0027s influence on global climate, specifically it should help set the bounds for the upper limits on how fast the ocean circulation might change in this region of the world, which is of high societal relevance in this era of changing climate. Education and Outreach (E/O): These activities are grouped into four categories: i) increasing student participation in polar research by fully integrating undergraduate through post-doctoral students into research programs; ii) promotion of K-12 teaching and learning programs by providing information via a cruise website and in-school talks, iii) making the data collected available to the wider research community via data archives such as Seamounts Online and the Seamount Biogeographic Network and iv) reaching a larger public audience through such venues as interviews in the popular media.", "east": -35.0, "geometry": ["POINT(-52.75 -58)"], "keywords": "Biota; Corals; Cruise Report; Drake Passage; NBP1103; Oceans; Sample/collection Description; Sample/Collection Description; Southern Ocean", "locations": "Southern Ocean; Drake Passage", "north": -54.5, "nsf_funding_programs": null, "persons": "Robinson, Laura", "project_titles": "Collaborative Research: Historic Perspectives on Climate and Biogeography from Deep-sea Corals in the Drake Passage", "projects": [{"proj_uid": "p0000514", "repository": "USAP-DC", "title": "Collaborative Research: Historic Perspectives on Climate and Biogeography from Deep-sea Corals in the Drake Passage"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -61.5, "title": "Historic Perspectives on Climate and Biogeography from Deep-Sea Corals in the Drake Passage", "uid": "600114", "west": -70.5}, {"awards": null, "bounds_geometry": null, "date_created": "Wed, 06 Apr 2005 00:00:00 GMT", "description": "This data set consists of cosmogenic nuclide concentrations in samples from bedrock surfaces in the Ford Ranges, Marie Byrd Land, West Antarctica. These surfaces have been exposed by ice retreat since the last glacial maximum, approximately 10,500 years ago. However, the majority of samples contain nuclide concentrations indicating much longer and more complicated exposure histories. The primary data are concentrations of the cosmic-ray-produced nuclides Be-10 and Al-26 measured in quartz, and Cl-36 measured in K-feldspar, sample locations, and the duration of recent exposure inferred from measurements on co-existing glacial erratics. In addition, the data set contains detailed information about the sites and samples, chemical compositions of the minerals analyzed and compositions of the host rocks, as required to compute nuclide production rates. This information is provided so that the data can be re-interpreted if nuclide production rates or correction factors are revised in future.", "east": null, "geometry": null, "keywords": null, "locations": null, "north": null, "nsf_funding_programs": null, "persons": "Stone, John", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": null, "title": "Cosmogenic nuclide data for bedrock samples from the Ford Ranges, Marie Byrd Land, West Antarctica", "uid": "600002", "west": null}, {"awards": "9615292 Wahlen, Martin", "bounds_geometry": ["POINT(158.71 -77.8)"], "date_created": "Tue, 01 Jan 2002 00:00:00 GMT", "description": "These data describe the concentration and carbon-isotopic composition (d13CO2) of atmospheric CO2 from air trapped in ice between 27,000 and 1,300 years before present from Taylor Dome, Antarctica. Data are used to investigate the causes of the CO2 concentration increase that occurred during the transition between the last glacial maximum (LGM) and the Holocene. Data are in tab-delimited ASCII and Excel formats, and are available via ftp.", "east": 158.71, "geometry": ["POINT(158.71 -77.8)"], "keywords": "Antarctica; Atmosphere; Chemistry:fluid; Chemistry:Fluid; Geochemistry; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Core Records; Paleoclimate; Taylor Dome; Taylor Dome Ice Core", "locations": "Taylor Dome; Antarctica", "north": -77.8, "nsf_funding_programs": "Antarctic Glaciology", "persons": "Wahlen, Martin", "project_titles": "Carbon Dioxide and Carbon Isotopes in the Taylor Dome and Vostok Ice Cores", "projects": [{"proj_uid": "p0000153", "repository": "USAP-DC", "title": "Carbon Dioxide and Carbon Isotopes in the Taylor Dome and Vostok Ice Cores"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.8, "title": "Carbon-Isotopic Composition of Atmospheric CO2 since the Last Glacial Maximum", "uid": "609108", "west": 158.71}]
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Dataset Title/Abstract/Map | NSF Award(s) | Date Created | PIs / Scientists | Project Links | Abstract | Bounds Geometry | Geometry | Selected | Visible |
---|---|---|---|---|---|---|---|---|---|
VSMOW-SLAP d170, d180, and 17O-excess data from WAIS Divide Ice Core Project, Siple Dome and Taylor Dome
|
None | 2023-10-13 | Steig, Eric J.; Schoenemann, Spruce | No project link provided | This data set contains the VSMOW-SLAP d170, d180, and 170-excess data from the WAIS Divide Ice Core Project, Siple Dome and Taylor Dome, along with the published and VSMOW-SLAP normalized d170, d180, and 170-excess for Vostok [Landais et al.2008], EPICA Dome C and Talos Dome [Wrinkler et al.,2012]. The data cover the Last Glacial Maximum (25-20 ka), through the Early Holocene (12-9 ka) and into present-day (past 2 kyr). | ["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))"] | ["POINT(0 -89.999)"] | false | false |
Atmospheric methane across the Last Glacial Maximum and deglaciation from the GISP2, NEEM and WAIS Divide ice cores
|
1745078 |
2023-10-05 | Riddell-Young, Benjamin; Martin, Kaden; Rosen, Julia; Lee, James; Edwards, Jon S.; Brook, Edward J. |
Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores |
This dataset includes measurements of atmospheric methane from samples from the NEEM, GISP2 and WAIS Divide ice cores. All measurements were made at the Oregon State University Ice Core and Quaternary Geochemistry Laboratory (Corvallis, OR) using an established analytical system. 433 samples from the NEEM ice core were measured between 1420 and 1560m depths. A measurement uncertainty ranging from 2.8 to 4.2 ppb, depending on the measurement year, was determined from replicate samples. 340 samples from the GISP2 ice core were measured between 1740 and 2060m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. All GISP2 and NEEM data were corrected for excess methane contamination using the established relationship between excess methane and Ca2+ (Lee et al., 2020). Both corrected and uncorrected data are included in the publication. 340 samples from the GISP2 ice core were measured between 1957 and 3081m depths. A measurement uncertainty ranging from 3.1 to 3.4 ppb, depending on the measurement year, was determined from replicate samples. Depths reflect the mid-points of the depth range of each samples, which is typically ~8cm. All replicate measurements are included in the dataset. Lee, J. E. et al. Excess methane in Greenland ice cores associated with high dust concentrations. Geochimica et cosmochimica acta 270, 409-430 (2020). | ["POINT(-112.05 -79.28)"] | ["POINT(-112.05 -79.28)"] | false | false |
Atmospheric methane interpolar difference and four-box troposphere model output across the Last Glacial Maximum and Deglaciation
|
1745078 |
2023-10-02 | Riddell-Young, Benjamin; Rosen, Julia; Buizert, Christo; Martin, Kaden; Lee, James; Edwards, Jon S.; Mühl, Michaela; Schmitt, Jochen; Fischer, Hubertus; Blunier, Thomas; Brook, Edward J. |
Tracing Past Methane Variations with Stable Isotopes in Antarctic Ice Cores |
This dataset includes estimates of the atmospheric methane relative interpolar difference (rIPD) across the Last Glacial Maximum and Deglaciation. The rIPD was calculated using discrete, high-resolution methane measurements from the WAIS Divide, NEEM and GISP2 ice cores. Two independent IPD records were determined: One using NEEM and WAIS and one using GISP2 and WAIS. The dataset includes rIPD values calculated using both Greenland methane data both corrected and uncorrected for excess methane (Lee et al., 2020). The rIPD was calculated by smoothing each methane record and synchronizing them to the WD2014 gas age scale. 1-sigma rIPD uncertainties are included. This dataset also includes the output of the four-box troposphere model used to interpret the rIPD. For both excess methane-corrected records, the model output and 1-sigma uncertainty is provided for northern extratropical (30N - 90N) and total tropical (30S - 30N) sources in Tg yr-1. For the NEEM-derived rIPD, sections of the rIPD where atmospheric methane changed rapidly were deemed untrustworthy were removed from the dataset. Lee, J. E. et al. Excess methane in Greenland ice cores associated with high dust concentrations. Geochimica et cosmochimica acta 270, 409-430 (2020). | ["POINT(-112.05 -79.28)"] | ["POINT(-112.05 -79.28)"] | false | false |
Salmon Valley Radiocarbon Data
|
0944150 |
2022-04-20 | Hall, Brenda |
Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles |
This dataset includes radiocarbon dates of benthic algal mats associated with last glacial maximum Ross Sea drift in Salmon Valley, Royal Society Range. | ["POLYGON((163.7 -77.9,163.79 -77.9,163.88 -77.9,163.97 -77.9,164.06 -77.9,164.15 -77.9,164.24 -77.9,164.33 -77.9,164.42 -77.9,164.51 -77.9,164.6 -77.9,164.6 -77.91,164.6 -77.92,164.6 -77.93,164.6 -77.94,164.6 -77.95,164.6 -77.96,164.6 -77.97,164.6 -77.98,164.6 -77.99,164.6 -78,164.51 -78,164.42 -78,164.33 -78,164.24 -78,164.15 -78,164.06 -78,163.97 -78,163.88 -78,163.79 -78,163.7 -78,163.7 -77.99,163.7 -77.98,163.7 -77.97,163.7 -77.96,163.7 -77.95,163.7 -77.94,163.7 -77.93,163.7 -77.92,163.7 -77.91,163.7 -77.9))"] | ["POINT(164.15 -77.95)"] | false | false |
Royal Society Range Headland Moraine Belt Radiocarbon Data
|
0944150 |
2022-04-20 | Hall, Brenda |
Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles |
This dataset contains radiocarbon dates of benthic algal (cyanobacterial) mats within moraines associated with Ross Sea drift on the headlands of the Royal Society Range and covers the time period ~12-20 ka. | ["POLYGON((163.5 -77.3,163.65 -77.3,163.8 -77.3,163.95 -77.3,164.1 -77.3,164.25 -77.3,164.4 -77.3,164.55 -77.3,164.7 -77.3,164.85 -77.3,165 -77.3,165 -77.39,165 -77.48,165 -77.57,165 -77.66,165 -77.75,165 -77.84,165 -77.93,165 -78.02,165 -78.11,165 -78.2,164.85 -78.2,164.7 -78.2,164.55 -78.2,164.4 -78.2,164.25 -78.2,164.1 -78.2,163.95 -78.2,163.8 -78.2,163.65 -78.2,163.5 -78.2,163.5 -78.11,163.5 -78.02,163.5 -77.93,163.5 -77.84,163.5 -77.75,163.5 -77.66,163.5 -77.57,163.5 -77.48,163.5 -77.39,163.5 -77.3))"] | ["POINT(164.25 -77.75)"] | false | false |
Marshall Valley U-Series Data
|
1643248 0944150 |
2022-03-01 | Hall, Brenda |
Response of the Antarctic Ice Sheet to the last great global warming Sensitivity of the Antarctic Ice Sheet to Climate Change over the Last Two Glacial/Interglacial Cycles |
This dataset includes 234U/230Th chronologic data for lacustrine carbonates associated with Marshall drift in Marshall Valley, Royal Society Range. These samples are from ice-dammed lake deposits associated with a grounded ice sheet that blocked the valley mouth. Sample chemistry was done at the University of Maine geochemistry laboratory. Processed samples were analyzed on a multicollector ICP-MS at the University of Oxford. Corrected ages reflect a detrital correction based on typical upper-crustal (230Th/232Th) values of 1.21 with a 50% assumed error. | ["POLYGON((164 -78,164.04 -78,164.08 -78,164.12 -78,164.16 -78,164.2 -78,164.24 -78,164.28 -78,164.32 -78,164.36 -78,164.4 -78,164.4 -78.01,164.4 -78.02,164.4 -78.03,164.4 -78.04,164.4 -78.05,164.4 -78.06,164.4 -78.07,164.4 -78.08,164.4 -78.09,164.4 -78.1,164.36 -78.1,164.32 -78.1,164.28 -78.1,164.24 -78.1,164.2 -78.1,164.16 -78.1,164.12 -78.1,164.08 -78.1,164.04 -78.1,164 -78.1,164 -78.09,164 -78.08,164 -78.07,164 -78.06,164 -78.05,164 -78.04,164 -78.03,164 -78.02,164 -78.01,164 -78))"] | ["POINT(164.2 -78.05)"] | false | false |
Circum-Antarctic grounding-line sinuosity
|
1246353 1745043 1745055 |
2021-11-10 | Simkins, Lauren; Stearns, Leigh; Riverman, Kiya |
Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum. |
The dataset here allows exploration of the causes and significance of Antarctic grounding-line sinuosity by coupling observations of contemporary Antarctic grounding lines and paleo-grounding lines expressed as ice-marginal landforms on the Ross Sea continental shelf. Modern grounding lines are derived from the MEaSUREs Version 2 Differential Satellite Radar Interferometry dataset with spatial resolutions of 25-120 m spanning February 1992 to December 2014 (Rignot et al., 2016; Mouginot et al., 2017). The boundaries of individual grounding lines representative of individual glacial catchments (n=664) were delineated by the inflection points of the shear strain rate, εxy (c.f Van der Veen et al., 2011). Sinuosity was calculated as the ratio of the true length, orthogonal to ice-flow direction, of the grounding lines and the straight line length between end-points and in units of km/km. Raster data were extracted at 1-km points along each grounding line; the mean was calculated for each grounding line and merged in a table with sinuosity data. A dataset of 6,275 paleo-grounding lines expressed as ice-marginal landforms on the deglaciated western Ross Sea continental shelf are used in this study, originally published by Simkins et al., 2018. The ice-marginal landforms were mapped from multibeam echo sounder data that was collected onboard the RVIB Nathaniel B. Palmer (NBP) 15-02 cruise using a Kongsberg EM122 operating in dual swath mode at 12 kHz frequency with 30-60% swath overlap (Cruise DOI: 10.7284/901477). The resulting bathymetry data was gridded at 20-40 m with decimeter vertical elevation resolution depending on water depth and sea-state. Sinuosity is calculated as a ratio of true (mapped) landform length, measured in the across paleo-ice flow direction at the crest of the landform, to the straight line distance between the mapped landform endpoints and in units of km/km. To compare modern and paleo-grounding lines, we use a consistent length scale by segmenting the grounding lines into 2-km sections for the two datasets (modern, n=12,966; paleo, n=5,832), even though this eliminates grounding lines that are less than 2-km long and thus results in 1 modern and 3,873 paleo-grounding lines removed. The full-length and 2-km segmented groundings lines are provided as shapefiles "InSAR_groundinglines_full" and "InSAR_groundinglines_2km", the paleo-grounding lines are provided as shapefiles "RossSea_icemarginal_full" and "RossSea_icemarginal_2km", and points marking modern grounding lines retreat from repeat InSAR surveys are provided as shapefile "InSAR_retreat_points", all stored together in a geodatabase named "Antarctic_groundinglines.gbd". Additional grounding line metrics, including length, sinuosity, bed roughness, and bed slope for modern and paleo-grounding lines, and height-above-buoyancy gradient, ice-flow velocity, presence of pinning points and ice shelves are provided for modern grounding lines. The published dataset was compiled and analyzed in the article "Controls on circum-Antarctic grounding-line sinuosity " by Simkins, L.M., Stearns, L.A., and Riverman, K.L, which will be submitted to a peer-review journal in November 2021. References Mouginot, J., B. Scheuchl, and E. Rignot. 2017. MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar, Version 2. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. Rignot, E., J. Mouginot, and B. Scheuchl. 2016. MEaSUREs Antarctic Grounding Line from Differential Satellite Radar Interferometry, Version 2. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. Simkins, L. M., Greenwood, S. L., & Anderson, J. B. (2018). Diagnosing ice sheet grounding line stability from landform morphology. The Cryosphere, 12(8), 2707-2726. Van der Veen, C. J., J. C. Plummer, & L. A. Stearns. (2011). Controls on the recent speed up of Jakobshavn Isbræ, West Greenland. Journal of Glaciology, 57(204), 770-782 | ["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))"] | ["POINT(0 -89.999)"] | false | false |
Pennell Trough, Ross Sea bathymetry and glacial landforms
|
1246353 1745043 1745055 |
2021-10-04 | Greenwood, Sarah; Munevar Garcia, Santiago; Eareckson, Elizabeth; Anderson, John; Prothro, Lindsay; Simkins, Lauren |
Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum. Collaborative Research: Topographic controls on Antarctic Ice Sheet grounding line retreat - integrating models and observations |
Bathymetry from multibeam echo sounding data in Pennell Trough, Ross Sea, Antarctica was collected onboard the RVIB Nathaniel B. Palmer (NBP) 15-02 cruise using a Kongsberg EM122 operating in dual swath mode at 12 kHz frequency with a 1°×1° beam width, swath angular coverage set to 62°×62°, and 30-60% overlap between survey lines. All raw, ping-edited geophysical data collected on NBP15-02 can be accessed using the Marine Geoscience Data System (Cruise DOI: 10.7284/901477). The bathymetry dataset here is gridded at 20-m resolution with a water depth-dependent vertical resolution on the order of decimeters. Two shapefiles are provided for ice-marginal landforms and meltwater landforms observable in the bathymetry data. The purpose of collecting the bathymetry data on cruise NBP15-02 was to better understand the glacial history of the Ross Sea, and the dataset, inclusive of bathymetry data and shapefiles of glacial landforms, from Pennell Trough are used to understand impacts on subglacial channel morphology and organization during the deglaciation of the region following the Last Glacial Maximum. The published dataset was used and analyzed in the article "Topographic controls on channelized meltwater in the subglacial environment" by Simkins, L.M., Greenwood, S.L., Munevar Garcia, S., Eareckson, E.A., Anderson, J.B., and Prothro, L.O, which was published in Geophysical Research Letters in 2021 (DOI: 10.1029/2021GL094678). | ["POLYGON((174 -75,174.4 -75,174.8 -75,175.2 -75,175.6 -75,176 -75,176.4 -75,176.8 -75,177.2 -75,177.6 -75,178 -75,178 -75.2,178 -75.4,178 -75.6,178 -75.8,178 -76,178 -76.2,178 -76.4,178 -76.6,178 -76.8,178 -77,177.6 -77,177.2 -77,176.8 -77,176.4 -77,176 -77,175.6 -77,175.2 -77,174.8 -77,174.4 -77,174 -77,174 -76.8,174 -76.6,174 -76.4,174 -76.2,174 -76,174 -75.8,174 -75.6,174 -75.4,174 -75.2,174 -75))"] | ["POINT(176 -76)"] | false | false |
17O excess from WAIS Divide, 0 to 25 ka BP
|
1043092 |
2020-12-22 | Steig, Eric J.; Schoenemann, Spruce |
Collaborative Research: Stable Isotopes of Ice in the Transition and Glacial Sections of the WAIS Divide Deep Ice Core |
This data set contains the VSMOW-SLAP d17O, d18O, and 17O-excess data from the WAIS Divide Ice Core Project, Siple Dome and Taylor Dome, along with the published and VSMOW-SLAP normalized d17O, d18O, and 17O-excess for Vostok [Landais et al. 2008], EPICA Dome C and Talos Dome [Winkler et al., 2012]. The data cover the Last Glacial Maximum (25-20 ka), through the Early Holocene (12-9 ka) and into present-day (past 2 kyr) | ["POLYGON((-158.72 -77.79,-154.056 -77.79,-149.392 -77.79,-144.728 -77.79,-140.064 -77.79,-135.4 -77.79,-130.736 -77.79,-126.072 -77.79,-121.408 -77.79,-116.744 -77.79,-112.08 -77.79,-112.08 -78.178,-112.08 -78.566,-112.08 -78.954,-112.08 -79.342,-112.08 -79.73,-112.08 -80.118,-112.08 -80.506,-112.08 -80.894,-112.08 -81.282,-112.08 -81.67,-116.744 -81.67,-121.408 -81.67,-126.072 -81.67,-130.736 -81.67,-135.4 -81.67,-140.064 -81.67,-144.728 -81.67,-149.392 -81.67,-154.056 -81.67,-158.72 -81.67,-158.72 -81.282,-158.72 -80.894,-158.72 -80.506,-158.72 -80.118,-158.72 -79.73,-158.72 -79.342,-158.72 -78.954,-158.72 -78.566,-158.72 -78.178,-158.72 -77.79))"] | ["POINT(-135.4 -79.73)"] | false | false |
Gas and Dust Measurements for Taylor Glacier and Taylor Dome Ice Cores
|
1246148 1245821 1245659 |
2019-08-12 | 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. |
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 |
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 (Δage) 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 Δage did not exceed 3 ka. The difference in Δage 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. | ["POINT(162.167 -77.733)"] | ["POINT(162.167 -77.733)"] | false | false |
NBP1502A Cruise Core Data
|
1246353 |
2018-02-05 | Simkins, Lauren; Anderson, John; Prothro, Lindsay |
Evidence for Paleo Ice Stream Collapse in the Western Ross Sea since the Last Glacial Maximum. |
Dataset includes details of cores collected as part of cruise NBP1502A, a list of radiocarbon-dated samples and samples to be radiocarbon-dated, and grain-size data from select NBP1502A cores. | ["POLYGON((-180 -74.37,-178.85 -74.37,-177.7 -74.37,-176.55 -74.37,-175.4 -74.37,-174.25 -74.37,-173.1 -74.37,-171.95 -74.37,-170.8 -74.37,-169.65 -74.37,-168.5 -74.37,-168.5 -74.747,-168.5 -75.124,-168.5 -75.501,-168.5 -75.878,-168.5 -76.255,-168.5 -76.632,-168.5 -77.009,-168.5 -77.386,-168.5 -77.763,-168.5 -78.14,-169.65 -78.14,-170.8 -78.14,-171.95 -78.14,-173.1 -78.14,-174.25 -78.14,-175.4 -78.14,-176.55 -78.14,-177.7 -78.14,-178.85 -78.14,180 -78.14,178.48 -78.14,176.96 -78.14,175.44 -78.14,173.92 -78.14,172.4 -78.14,170.88 -78.14,169.36 -78.14,167.84 -78.14,166.32 -78.14,164.8 -78.14,164.8 -77.763,164.8 -77.386,164.8 -77.009,164.8 -76.632,164.8 -76.255,164.8 -75.878,164.8 -75.501,164.8 -75.124,164.8 -74.747,164.8 -74.37,166.32 -74.37,167.84 -74.37,169.36 -74.37,170.88 -74.37,172.4 -74.37,173.92 -74.37,175.44 -74.37,176.96 -74.37,178.48 -74.37,-180 -74.37))"] | ["POINT(178.15 -76.255)"] | false | false |
Prokaryotic cell concentration record from the WAIS Divide ice core
|
0839075 |
2017-12-12 | Santibanez, Pamela; Priscu, John |
Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core |
This data set includes raw concentration of prokaryotic cells for the WAIS Divide deep core, WDC06A, from 1,764 m to 2,709 m. Data were collected by a method that combines acquisition of discrete samples using a continuous ice-core melting system (McConnell et al., 2002) coupled with flow cytometry of DNA-stained samples. The method is described in detail in Santibanez et al., 2016. We present the first long-term, highly resolved prokaryotic cell concentration record obtained from a polar ice core. This record, obtained from the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core, spanned from the Last Glacial Maximum (LGM) to the early Holocene (EH) and showed distinct fluctuations in prokaryotic cell concentration coincident with major climatic states. This record provided strong evidence that airborne prokaryotic cell deposition differed during the LGM, LDG and EH, and that these changes in cell densities could be explained by different environmental conditions during each of these climatic periods. Our observations provide the first ice core time-series evidence for a prokaryotic response to long-term climatic and environmental processes. | ["POINT(-112 -79)"] | ["POINT(-112 -79)"] | false | false |
WD2014: Timescale for WAIS Divide Core 2006 A (WDC-06A)
|
0944197 |
2017-03-28 | Fudge, T. J. |
Collaborative Research: Establishing the Chronology and Histories of Accumulation and Ice Dynamics for the WAIS Divide Core |
The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep ice core that provides Antarctic climate records of the past ~68 ka at unprecedented temporal resolution. The upper 2850 m (back to 31.2 ka BP) have been dated using annual-layer counting. Here we present a chronology for the deep part of the core (67.8-31.2 ka BP), which is based on stratigraphic matching to annual-layer-counted Greenland ice cores using globally well-mixed atmospheric methane. We calculate the WD gas age-ice age difference (Delta age) using a combination of firn densification modeling, ice-flow modeling, and a data set of d15N-N2, a proxy for past firn column thickness. The largest Delta age at WD occurs during the Last Glacial Maximum, and is 525 +/- 120 years. Internally consistent solutions can be found only when assuming little to no influence of impurity content on densification rates, contrary to a recently proposed hypothesis. We synchronize the WD chronology to a linearly scaled version of the layer-counted Greenland Ice Core Chronology (GICC05), which brings the age of Dansgaard-Oeschger (DO) events into agreement with the U/Th absolutely dated Hulu Cave speleothem record. The small Delta age at WD provides valuable opportunities to investigate the timing of atmospheric greenhouse gas variations relative to Antarctic climate, as well as the interhemispheric phasing of the \"bipolar seesaw\". We present the WD2014 chronology for the upper part (0-2850 m; 31.2 ka BP) of the West Antarctic Ice Sheet (WAIS) Divide (WD) ice core. The chronology is based on counting of annual layers observed in the chemical, dust and electrical conductivity records. These layers are caused by seasonal changes in the source, transport, and deposition of aerosols. The measurements were interpreted manually and with the aid of two automated methods. We validated the chronology by comparing to two high-accuracy, absolutely dated chronologies. For the Holocene, the cosmogenic isotope records of 10Be from WAIS Divide and 14C for IntCal13 demonstrated that WD2014 was consistently accurate to better than 0.5% of the age. For the glacial period, comparisons to the Hulu Cave chronology demonstrated that WD2014 had an accuracy of better than 1% of the age at three abrupt climate change events between 27 and 31ka. WD2014 has consistently younger ages than Greenland ice core chronologies during most of the Holocene. For the Younger Dryas-Preboreal transition (11.595 ka; 24 years younger) and the Bolling-Allerod Warming (14.621 ka; 7 years younger), WD2014 ages are within the combined uncertainties of the timescales. Given its high accuracy, WD2014 can become a reference chronology for the Southern Hemisphere, with synchronization to other chronologies feasible using high-quality proxies of volcanism, solar activity, atmospheric mineral dust, and atmospheric methane concentrations. | ["POINT(-112.1115 -79.481)"] | ["POINT(-112.1115 -79.481)"] | false | false |
Fluorescence spectroscopy data from the West Antarctic Ice Sheet (WAIS) Divide ice core, WDC06A
|
0839075 |
2017-03-06 | Priscu, John; D'Andrilli, Juliana |
Collaborative Research: Integrated High Resolution Chemical and Biological Measurements on the Deep WAIS Divide Core |
This data set include depth (WDC06A-7 dating) and fluorescence intensity measurements for five fluorophore regions (A, C, M, B, and T) commonly found in natural organic matter. Data from 1300-1700m, 1700-2100m, and 2100-2700m correspond to the early Holocene, deglaciation period, and the Last Glacial Maximum. | ["POINT(-112.08648 -79.46763)"] | ["POINT(-112.08648 -79.46763)"] | false | false |
A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea
|
1043485 |
2015-01-01 | Kurz, Mark D.; Curtice, Josh |
Collaborative Research: A New Reconstruction of the Last West Antarctic Ice Sheet Deglaciation in the Ross Sea |
This award supports a project to develop a better understanding of the response of the WAIS to climate change. The timing of the last deglaciation of the western Ross Sea will be improved using in situ terrestrial cosmogenic nuclides (3He, 10Be, 14C, 26Al, 36Cl) to date glacial erratics at key areas and elevations along the western Ross Sea coast. A state-of-the art ice sheet-shelf model will be used to identify mechanisms of deglaciation of the Ross Sea sector of WAIS. The model results and forcing will be compared with observations including the new cosmogenic data proposed here, with the aim of better determining and understanding the history and causes of WAIS deglaciation in the Ross Sea. There is considerable uncertainty, however, in the history of grounding line retreat from its last glacial maximum position, and virtually nothing is known about the timing of ice- surface lowering prior to ~10,000 years ago. Given these uncertainties, we are currently unable to assess one of the most important questions regarding the last deglaciation of the global ice sheets, namely as to whether the Ross Sea sector of WAIS contributed significantly to meltwater pulse 1A (MWP-1A), an extraordinarily rapid (~500-year duration) episode of ~20 m sea-level rise that occurred ~14,500 years ago. The intellectual merit of this project is that recent observations of startling changes at the margins of the Greenland and Antarctic ice sheets indicate that dynamic responses to warming may play a much greater role in the future mass balance of ice sheets than considered in current numerical projections of sea level rise. The broader impacts of this work are that it has direct societal relevance to developing an improved understanding of the response of the West Antarctic ice sheet to current and possible future environmental changes including the sea-level response to glacier and ice sheet melting due to global warming. The PI will communicate results from this project to a variety of audiences through the publication of peer-reviewed papers and by giving talks to public audiences. Finally the project will support a graduate student and undergraduate students in all phases of field-work, laboratory work and data interpretation. | ["POLYGON((163.4 -77.47989,163.9848 -77.47989,164.5696 -77.47989,165.1544 -77.47989,165.7392 -77.47989,166.324 -77.47989,166.9088 -77.47989,167.4936 -77.47989,168.0784 -77.47989,168.6632 -77.47989,169.248 -77.47989,169.248 -77.565701,169.248 -77.651512,169.248 -77.737323,169.248 -77.823134,169.248 -77.908945,169.248 -77.994756,169.248 -78.080567,169.248 -78.166378,169.248 -78.252189,169.248 -78.338,168.6632 -78.338,168.0784 -78.338,167.4936 -78.338,166.9088 -78.338,166.324 -78.338,165.7392 -78.338,165.1544 -78.338,164.5696 -78.338,163.9848 -78.338,163.4 -78.338,163.4 -78.252189,163.4 -78.166378,163.4 -78.080567,163.4 -77.994756,163.4 -77.908945,163.4 -77.823134,163.4 -77.737323,163.4 -77.651512,163.4 -77.565701,163.4 -77.47989))"] | ["POINT(166.324 -77.908945)"] | false | false |
East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains
|
1043619 |
2014-01-01 | Hemming, Sidney R. |
Collaborative Research: East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains |
Intellectual Merit: The PIs proposed a provenance study of glacial deposits in the Ross Embayment that will provide a broad scale geochronologic survey of detrital minerals in till to help characterize bedrock beneath the East Antarctic ice sheet and constrain Antarctica?s glacial history. This project capitalizes on previous investments in field sampling. Analytical tools applied to single mineral grains extracted from existing collections of glacial till will generate ?fingerprints? of East Antarctic outlet glaciers and West Antarctic till to refine paleo-ice flow models for the Ross Embayment during the last glacial maximum, older records from ANDRILL cores, and to assess IRD sources in the Southern Ocean. New provenance tracers will include a suite of geochronological methods that together provide greater insights into the orogenic and erosional history the region. This project will include U/Pb of detrital zircons, (U-Th)/He on a subset of the U/Pb dated zircons, as well as Ar-Ar of detrital hornblende, mica and feldspars. Broader Impacts: This research will train one M.S. student at IUPUI, a Ph.D. student at Columbia, and several undergraduates at both institutions. Graduate students involved in the project will be involved in mentoring undergraduate researchers. Incorporation of research discoveries will be brought into the classroom by providing concrete examples and exercises at the appropriate level. Licht and Columbia graduate student E. Pierce are developing outreach projects with local secondary school teachers to investigate the provenance of glacial materials in their local areas. The research will have broad applicability to many fields. | ["POLYGON((-180 -63.997,-179.7982 -63.997,-179.5964 -63.997,-179.3946 -63.997,-179.1928 -63.997,-178.991 -63.997,-178.7892 -63.997,-178.5874 -63.997,-178.3856 -63.997,-178.1838 -63.997,-177.982 -63.997,-177.982 -66.3324,-177.982 -68.6678,-177.982 -71.0032,-177.982 -73.3386,-177.982 -75.674,-177.982 -78.0094,-177.982 -80.3448,-177.982 -82.6802,-177.982 -85.0156,-177.982 -87.351,-178.1838 -87.351,-178.3856 -87.351,-178.5874 -87.351,-178.7892 -87.351,-178.991 -87.351,-179.1928 -87.351,-179.3946 -87.351,-179.5964 -87.351,-179.7982 -87.351,180 -87.351,172.54273 -87.351,165.08546 -87.351,157.62819 -87.351,150.17092 -87.351,142.71365 -87.351,135.25638 -87.351,127.79911 -87.351,120.34184 -87.351,112.88457 -87.351,105.4273 -87.351,105.4273 -85.0156,105.4273 -82.6802,105.4273 -80.3448,105.4273 -78.0094,105.4273 -75.674,105.4273 -73.3386,105.4273 -71.0032,105.4273 -68.6678,105.4273 -66.3324,105.4273 -63.997,112.88457 -63.997,120.34184 -63.997,127.79911 -63.997,135.25638 -63.997,142.71365 -63.997,150.17092 -63.997,157.62819 -63.997,165.08546 -63.997,172.54273 -63.997,-180 -63.997))"] | ["POINT(143.72265 -75.674)"] | false | false |
Historic Perspectives on Climate and Biogeography from Deep-Sea Corals in the Drake Passage
|
0944474 |
2011-01-01 | Robinson, Laura |
Collaborative Research: Historic Perspectives on Climate and Biogeography from Deep-sea Corals in the Drake Passage |
Polar oceans are the main sites of deep-water formation and are critical to the exchange of heat and carbon between the deep ocean and the atmosphere. This award "Historic perspectives on climate and biogeography from deep-sea corals in the Drake Passage" will address the following specific research questions: What was the radiocarbon content of the Southern Ocean during the last glacial maximum and during past rapid climate change events? and What are the major controls on the past and present distribution of cold-water corals within the Drake Passage and adjacent continental shelves? Testing these overall questions will allow the researchers to better understand how processes in the Southern Ocean are linked to climate change over millennia. This award is being funded by the Antarctic Earth Sciences Program of NSF's Office of Polar Programs, Antarctic Division. INTELLECTUAL MERIT: The skeletons of deep-sea corals are abundant in the Southern Ocean, and can be dated using U-series techniques making them a useful archive of oceanographic history. By pairing U-series and radiocarbon analyses the awardees can reconstruct the radiocarbon content of seawater in the past, allowing them to address the research questions raised above. Collection of living deep-sea corals along with environmental data will allow them to address the broader biogeography questions posed above as well. The awardees are uniquely qualified to answer these questions in their respective labs via cutting edge technologies, and they have shown promising results from a preliminary pilot cruise to the area in 2008. BROADER IMPACTS: Societal Relevance: The proposed paleoclimate research will make significant advances toward constraining the Southern Ocean's influence on global climate, specifically it should help set the bounds for the upper limits on how fast the ocean circulation might change in this region of the world, which is of high societal relevance in this era of changing climate. Education and Outreach (E/O): These activities are grouped into four categories: i) increasing student participation in polar research by fully integrating undergraduate through post-doctoral students into research programs; ii) promotion of K-12 teaching and learning programs by providing information via a cruise website and in-school talks, iii) making the data collected available to the wider research community via data archives such as Seamounts Online and the Seamount Biogeographic Network and iv) reaching a larger public audience through such venues as interviews in the popular media. | ["POLYGON((-70.5 -54.5,-66.95 -54.5,-63.4 -54.5,-59.85 -54.5,-56.3 -54.5,-52.75 -54.5,-49.2 -54.5,-45.65 -54.5,-42.1 -54.5,-38.55 -54.5,-35 -54.5,-35 -55.2,-35 -55.9,-35 -56.6,-35 -57.3,-35 -58,-35 -58.7,-35 -59.4,-35 -60.1,-35 -60.8,-35 -61.5,-38.55 -61.5,-42.1 -61.5,-45.65 -61.5,-49.2 -61.5,-52.75 -61.5,-56.3 -61.5,-59.85 -61.5,-63.4 -61.5,-66.95 -61.5,-70.5 -61.5,-70.5 -60.8,-70.5 -60.1,-70.5 -59.4,-70.5 -58.7,-70.5 -58,-70.5 -57.3,-70.5 -56.6,-70.5 -55.9,-70.5 -55.2,-70.5 -54.5))"] | ["POINT(-52.75 -58)"] | false | false |
Cosmogenic nuclide data for bedrock samples from the Ford Ranges, Marie Byrd Land, West Antarctica
|
None | 2005-04-06 | Stone, John | No project link provided | This data set consists of cosmogenic nuclide concentrations in samples from bedrock surfaces in the Ford Ranges, Marie Byrd Land, West Antarctica. These surfaces have been exposed by ice retreat since the last glacial maximum, approximately 10,500 years ago. However, the majority of samples contain nuclide concentrations indicating much longer and more complicated exposure histories. The primary data are concentrations of the cosmic-ray-produced nuclides Be-10 and Al-26 measured in quartz, and Cl-36 measured in K-feldspar, sample locations, and the duration of recent exposure inferred from measurements on co-existing glacial erratics. In addition, the data set contains detailed information about the sites and samples, chemical compositions of the minerals analyzed and compositions of the host rocks, as required to compute nuclide production rates. This information is provided so that the data can be re-interpreted if nuclide production rates or correction factors are revised in future. | [] | [] | false | false |
Carbon-Isotopic Composition of Atmospheric CO2 since the Last Glacial Maximum
|
9615292 |
2002-01-01 | Wahlen, Martin |
Carbon Dioxide and Carbon Isotopes in the Taylor Dome and Vostok Ice Cores |
These data describe the concentration and carbon-isotopic composition (d13CO2) of atmospheric CO2 from air trapped in ice between 27,000 and 1,300 years before present from Taylor Dome, Antarctica. Data are used to investigate the causes of the CO2 concentration increase that occurred during the transition between the last glacial maximum (LGM) and the Holocene. Data are in tab-delimited ASCII and Excel formats, and are available via ftp. | ["POINT(158.71 -77.8)"] | ["POINT(158.71 -77.8)"] | false | false |