USAP-DC

{"dp_type": "Dataset", "free_text": "Pliocene"}

[{"awards": "1939146 Siddoway, Christine", "bounds_geometry": ["POLYGON((-109.1 -68.6,-108.94 -68.6,-108.78 -68.6,-108.61999999999999 -68.6,-108.46 -68.6,-108.3 -68.6,-108.14 -68.6,-107.98 -68.6,-107.82 -68.6,-107.66 -68.6,-107.5 -68.6,-107.5 -68.64,-107.5 -68.67999999999999,-107.5 -68.72,-107.5 -68.75999999999999,-107.5 -68.8,-107.5 -68.84,-107.5 -68.88,-107.5 -68.92,-107.5 -68.96,-107.5 -69,-107.66 -69,-107.82 -69,-107.98 -69,-108.14 -69,-108.3 -69,-108.46 -69,-108.61999999999999 -69,-108.78 -69,-108.94 -69,-109.1 -69,-109.1 -68.96,-109.1 -68.92,-109.1 -68.88,-109.1 -68.84,-109.1 -68.8,-109.1 -68.75999999999999,-109.1 -68.72,-109.1 -68.67999999999999,-109.1 -68.64,-109.1 -68.6))"], "date_created": "Tue, 27 Aug 2024 00:00:00 GMT", "description": "The table contains sample identifiers, location data, and geochronology data (U-Pb zircon dates; apatite fission track determinations) from selected intervals of sediment cores obtained at sites U1532 (A, B, C, G) and U1533 (A, B) recovered during IODP Expedition 379 to the outer Amundsen Sea, Antarctica.", "east": -107.5, "geometry": ["POINT(-108.3 -68.8)"], "keywords": "Amundsen Sea; Antarctica; Cryosphere; Geochronology; Marie Byrd Land; Subglacial Bedrock; Thermochronology", "locations": "Antarctica; Marie Byrd Land; Amundsen Sea; Amundsen Sea", "north": -68.6, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Siddoway, Christine", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.0, "title": "U-Pb zircon and apatite fission track dates for IRD (ice-rafted cobbles and mineral grains) from IODP379 drill sites", "uid": "601828", "west": -109.1}, {"awards": "2000992 Romans, Brian", "bounds_geometry": ["POLYGON((-174 -74.1667,-173.93 -74.1667,-173.86 -74.1667,-173.79 -74.1667,-173.72 -74.1667,-173.65 -74.1667,-173.58 -74.1667,-173.51000000000002 -74.1667,-173.44 -74.1667,-173.37 -74.1667,-173.3 -74.1667,-173.3 -74.25503,-173.3 -74.34336,-173.3 -74.43169,-173.3 -74.52002,-173.3 -74.60835,-173.3 -74.69668,-173.3 -74.78501,-173.3 -74.87334,-173.3 -74.96167,-173.3 -75.05,-173.37 -75.05,-173.44 -75.05,-173.51000000000002 -75.05,-173.58 -75.05,-173.65 -75.05,-173.72 -75.05,-173.79 -75.05,-173.86 -75.05,-173.93 -75.05,-174 -75.05,-174 -74.96167,-174 -74.87334,-174 -74.78501,-174 -74.69668,-174 -74.60835,-174 -74.52002,-174 -74.43169,-174 -74.34336,-174 -74.25503,-174 -74.1667))"], "date_created": "Wed, 10 Jul 2024 00:00:00 GMT", "description": "This data set includes grain size information from late Pliocene through Pleistocene aged sediment recovered in cores from International Ocean Discovery Program (IODP) Expedition 374 Sites U1524 and U1525, on the continental slope and rise of the Ross Sea margin. There are two types of particle size data: (1) laser diffraction (Mastersizer 3000) data of silt-range sediment subsampled from mm-scale thick laminae/beds, and (2) x-ray-monitored settling (SediGraph 5120) data from muddy intervals directly overlying the silt laminae/beds. For Site U1524, there are 100 samples of Mastersizer data coupled with 100 samples of SediGraph data. For Site U1525, there are 50 samples of Mastersizer data coupled with 50 samples of SediGraph data. For both sites, the analyzed samples span the depth range of the core that contains the silty laminae/beds. ", "east": -173.3, "geometry": ["POINT(-173.65 -74.60835)"], "keywords": "Antarctica; Cryosphere; Grain Size; Ross Sea", "locations": "Antarctica; Ross Sea", "north": -74.1667, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Romans, Brian W.; Varela, Natalia", "project_titles": "COLLABORATIVE RESEARCH: Orbital-scale Variability of the West Antarctic Ice Sheet and the Formation of Bottom Water in the Ross Sea during the Pliocene-Pleistocene", "projects": [{"proj_uid": "p0010227", "repository": "USAP-DC", "title": "COLLABORATIVE RESEARCH: Orbital-scale Variability of the West Antarctic Ice Sheet and the Formation of Bottom Water in the Ross Sea during the Pliocene-Pleistocene"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -75.05, "title": "Grain size of Plio-Pleistocene continental slope and rise sediments, Hillary Canyon, Ross Sea", "uid": "601807", "west": -174.0}, {"awards": "1939139 Scherer, Reed", "bounds_geometry": null, "date_created": "Thu, 27 Jun 2024 00:00:00 GMT", "description": "This dataset contains physical measurements of specimens of the Southern Ocean diatom Fragilariopsis kerguelensis. We used the image segmentation software SHERPA (Kloster et al., 2017) to make physical measurements of each valve including \"rectangularity\". F. kerguelensis rectangularity has been posited to change in response to Sea Surface Temperature, a relationship that we explore in this study by calculating SSTs using established and new valve rectangularity/SST calibrations. ", "east": null, "geometry": null, "keywords": "Amundsen Sea; Antarctica; Cryosphere; Oceanography; Sabrina Coast; Sea Surface Temperature; Southern Ocean", "locations": "Amundsen Sea; Antarctica; Sabrina Coast; Amundsen Sea; Southern Ocean; Antarctica; Sabrina Coast", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Ruggiero, Joseph", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Population morphometrics of the Southern Ocean diatom Fragilariopsis kerguelensis related to Sea Surface Temperature", "uid": "601804", "west": null}, {"awards": "1939139 Scherer, Reed", "bounds_geometry": null, "date_created": "Tue, 20 Feb 2024 00:00:00 GMT", "description": "", "east": null, "geometry": null, "keywords": "Antarctica; Biogenic Silica; Diatom", "locations": "Antarctica", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Scherer, Reed Paul; Furlong, Heather", "project_titles": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica", "projects": [{"proj_uid": "p0010451", "repository": "USAP-DC", "title": "Collaborative Research: Testing the Linchpin of WAIS Collapse with Diatoms and IRD in Pleistocene and Late Pliocene Strata of the Resolution Drift, Amundsen Sea, Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Pliocene diatom abundance, IODP 379-U1532", "uid": "601769", "west": null}, {"awards": "1914698 Hansen, Samantha", "bounds_geometry": ["POLYGON((90 -65,99 -65,108 -65,117 -65,126 -65,135 -65,144 -65,153 -65,162 -65,171 -65,180 -65,180 -67.5,180 -70,180 -72.5,180 -75,180 -77.5,180 -80,180 -82.5,180 -85,180 -87.5,180 -90,171 -90,162 -90,153 -90,144 -90,135 -90,126 -90,117 -90,108 -90,99 -90,90 -90,90 -87.5,90 -85,90 -82.5,90 -80,90 -77.5,90 -75,90 -72.5,90 -70,90 -67.5,90 -65))"], "date_created": "Wed, 24 Jan 2024 00:00:00 GMT", "description": "Recent investigations in polar environments have examined solid-Earth-ice-sheet feedbacks and have emphasized that glacial isostatic adjustment, tectonic, and geothermal forcings exert first-order control on the physical conditions at and below the ice-bed interface and must be taken into account when evaluating ice-sheet evolution. However, the solid-Earth structure beneath much of Antarctica is still poorly constrained given the sparse distribution of seismic stations across the continent and the generally low seismicity rate. One region of particular interest is the Wilkes Subglacial Basin (WSB) in East Antarctica. During the mid-Pliocene warm period, the WSB may have contributed 3-4 m to the estimated 20 m rise in sea-level, indicating that this region could also play an important role in future warming scenarios. However, the WSB may have experienced notable bedrock uplift since the Pliocene; therefore, past geologic inferences of instability may not serve as a simple analogue for the future.\r\n\r\nUsing records of ambient seismic noise recorded by both temporary and long-term seismic networks, along with a full-waveform tomographic inversion technique, we have developed improved images of the lithospheric structure beneath East Antarctica, including the WSB. Empirical Green\u2019s Functions with periods between 40 and 340 s have been extracted using a frequency-time normalization technique, and a finite-difference approach with a spherical grid has been employed to numerically model synthetic seismograms. Associated sensitivity kernels have also been constructed using a scattering integral method. Our results suggest the WSB is underlain by slow seismic velocities, with faster seismic structure beneath the adjacent Transantarctic Mountains and the Belgica Subglacial Highlands. This may indicate that the WSB is associated with a region of thinner lithosphere, possibly associated with prior continental rifting. The seismic heterogeneity highlighted in our model could have significant implications for understanding the geodynamic origin of WSB topography and its influence on ice-sheet behavior.\r\n\r\nThe model file and associated plotting scripts are provided.", "east": 180.0, "geometry": ["POINT(135 -77.5)"], "keywords": "Ambient Noise; Antarctica; East Antarctica; Geoscientificinformation; Seismic Tomography; Seismology", "locations": "Antarctica; East Antarctica", "north": -65.0, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Hansen, Samantha; Emry, Erica", "project_titles": "Collaborative Research: Resolving earth structure influence on ice-sheet stability in the Wilkes\r\nSubglacial Basin (RESISSt)", "projects": [{"proj_uid": "p0010204", "repository": "USAP-DC", "title": "Collaborative Research: Resolving earth structure influence on ice-sheet stability in the Wilkes\r\nSubglacial Basin (RESISSt)"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Full Waveform Ambient Noise Tomography for East Antarctica", "uid": "601763", "west": 90.0}, {"awards": "0838842 Passchier, Sandra", "bounds_geometry": ["POINT(167.0833 -77.8889)"], "date_created": "Mon, 14 Jun 2021 00:00:00 GMT", "description": "This dataset contains measurements of particle-size distributions on four intervals of diamicitites from ANDRILL Site AND-2A. Carbonate, and organic matter were removed through addition of 10mL aliquots of 30% H2O2 and 2mL aliquots of 10% HCl to ~50-100mL suspension on a hot plate. Dispersion was through heating with sodium pyrophosphate. Samples were measured on a Malvern Mastersizer 2000 with a Hydro 2000MU (A) accessory, using a Refractive index of 1.544 (Quartz) and an absorption coefficient of 0.9. Results are in (vol. %) per size class, with diameter range equivalent to the diameter of spheres with the same volume as measured particles.", "east": 167.0833, "geometry": ["POINT(167.0833 -77.8889)"], "keywords": "Antarctica; McMurdo Sound; Miocene; Particle Size; Pleistocene; Pliocene", "locations": "McMurdo Sound; Antarctica", "north": -77.8889, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Passchier, Sandra; Hansen, Melissa A.", "project_titles": "Determining Middle Miocene through Pliocene Changes in Paleo Ice-flow and Basal Ice Conditions in East Antarctica through Sedimentological Analyses of Core Samples", "projects": [{"proj_uid": "p0000147", "repository": "USAP-DC", "title": "Determining Middle Miocene through Pliocene Changes in Paleo Ice-flow and Basal Ice Conditions in East Antarctica through Sedimentological Analyses of Core Samples"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "ANDRILL", "south": -77.8889, "title": "Particle-size measurements for diamictites AND-2A sediment core, McMurdo Sound", "uid": "601452", "west": 167.0833}, {"awards": "1060080 TBD", "bounds_geometry": ["POINT(144 -65)"], "date_created": "Mon, 14 Jun 2021 00:00:00 GMT", "description": "This dataset contains measurements of terrigenous particle-size distributions on Pliocene sediment from Integrated Ocean Drilling Program Site U1359 on the Wilkes Land margin. Biogenic silica, carbonate, and organic matter were removed through addition of 10mL aliquots of 30% H2O2, 2mL aliquots of 10% HCl to ~50-100mL suspension on a hot plate, and after supernatant was removed, digestion in 0.2 N NaOH at ~85 degrees for 1 hour. Dispersion was through heating with sodium pyrophosphate. Samples were measured on a Malvern Mastersizer 2000 with a Hydro 2000MU (A) accessory, using a Refractive index of 1.6 (Illite) and an absorption coefficient of 0.9. Results are in (vol. %) per size class, with diameter range equivalent to the diameter of spheres with the same volume as measured particles.", "east": 144.0, "geometry": ["POINT(144 -65)"], "keywords": "Antarctica; Ice-Rafting; Marine Geoscience; Paleoclimate; Particle Size; Sediment Core Data; Wilkes Land", "locations": "Wilkes Land; Antarctica", "north": -65.0, "nsf_funding_programs": null, "persons": "Passchier, Sandra; Hansen, Melissa A.; Rosenberg, Jessica", "project_titles": null, "projects": null, "repositories": null, "science_programs": null, "south": -65.0, "title": "Particle-size distributions of Pliocene sediment from IODP Site U1359", "uid": "601450", "west": 144.0}, {"awards": "1443420 Dodd, Justin", "bounds_geometry": ["POINT(167.083333 -77.888889)"], "date_created": "Sun, 27 Oct 2019 00:00:00 GMT", "description": "The Andrill-1B (AND-1B) sediment core from under the Ross Ice Shelf in McMurdo Sound, Antarctica, recovered a mid to late Pliocene (~4.68 to 3.44 Ma) age diatomite unit with d18Odiatom values that range from +32.6 to +37.6 \u2030 (n=50 ", "east": 167.083333, "geometry": ["POINT(167.083333 -77.888889)"], "keywords": "And-1B; Andrill; Antarctica; Chemistry:sediment; Chemistry:Sediment; Delta 18O; Diatom; Mass Spectrometer; Oxygen Isotope; Paleoclimate; Pliocene; Sediment; Wais Project; West Antarctic Ice Sheet", "locations": "Antarctica; West Antarctic Ice Sheet", "north": -77.888889, "nsf_funding_programs": "Antarctic Earth Sciences", "persons": "Dodd, Justin; Abbott, Tirzah", "project_titles": "Diatom and Oxygen Isotope Evidence of Pliocene Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography", "projects": [{"proj_uid": "p0010042", "repository": "USAP-DC", "title": "Diatom and Oxygen Isotope Evidence of Pliocene Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "ANDRILL", "south": -77.888889, "title": "Diatom Oxygen Isotope Evidence of Pliocene (~4.68 to 3.44 Ma) Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography", "uid": "601220", "west": 167.083333}, {"awards": "1043554 Willenbring, Jane", "bounds_geometry": ["POINT(161.5 -77.5)"], "date_created": "Wed, 09 Nov 2016 00:00:00 GMT", "description": "The PIs propose to address the question of whether ice surface melting zones developed at high elevations during warm climatic phases in the Transantarctic Mountains. Evidence from sediment cores drilled by the ANDRILL program indicates that open water in the Ross Sea could have been a source of warmth during Pliocene and Pleistocene. The question is whether marine warmth penetrated inland to the ice sheet margins. The glacial record may be ill suited to answer this question, as cold-based glaciers may respond too slowly to register brief warmth. Questions also surround possible orbital controls on regional climate and ice sheet margins. Northern Hemisphere insolation at obliquity and precession timescales is thought to control Antarctic climate through oceanic or atmospheric connections, but new thinking suggests that the duration of Southern Hemisphere summer may be more important. The PIs propose to use high elevation alluvial deposits in the Transantarctic Mountains as a proxy for inland warmth. These relatively young fans, channels, and debris flow levees stand out as visible evidence for the presence of melt water in an otherwise ancient, frozen landscape. Based on initial analyses of an alluvial fan in the Olympus Range, these deposits are sensitive recorders of rare melt events that occur at orbital timescales. For their study they will 1) map alluvial deposits using aerial photography, satellite imagery and GPS assisted field surveys to establish water sources and to quantify parameters effecting melt water production, 2) date stratigraphic sequences within these deposits using OSL, cosmogenic nuclide, and interbedded volcanic ash chronologies, 3) use paired nuclide analyses to estimate exposure and burial times, and rates of deposition and erosion, and 4) use micro and regional scale climate modeling to estimate paleoenvironmental conditions associated with melt events.\nThis study will produce a record of inland melting from sites adjacent to ice sheet margins to help determine controls on regional climate along margins of the East Antarctic Ice Sheet to aid ice sheet and sea level modeling studies. The proposal will support several graduate and undergraduates. A PhD student will be supported on existing funding. The PIs will work with multiple K-12 schools to conduct interviews and webcasts from Antarctica and they will make follow up visits to classrooms after the field season is complete.", "east": 161.5, "geometry": ["POINT(161.5 -77.5)"], "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Cosmogenic Radionuclides; Geochronology; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Isotope; Sample/collection Description; Sample/Collection Description; Transantarctic Mountains", "locations": "Transantarctic Mountains; Antarctica", "north": -77.5, "nsf_funding_programs": null, "persons": "Willenbring, Jane", "project_titles": "Collaborative Research: Activation of high-elevation alluvial fans in the Transantarctic Mountains - a proxy for Plio-Pleistocene warmth along East Antarctic ice margins", "projects": [{"proj_uid": "p0000429", "repository": "USAP-DC", "title": "Collaborative Research: Activation of high-elevation alluvial fans in the Transantarctic Mountains - a proxy for Plio-Pleistocene warmth along East Antarctic ice margins"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -77.5, "title": "Activation of high-elevation alluvial fans in the Transantarctic Mountains - a proxy for Plio-Pleistocene warmth along East Antarctic ice margins", "uid": "600379", "west": 161.5}, {"awards": "1354231 Kowalewski, Douglas", "bounds_geometry": ["POLYGON((-160 -70,-156 -70,-152 -70,-148 -70,-144 -70,-140 -70,-136 -70,-132 -70,-128 -70,-124 -70,-120 -70,-120 -71.5,-120 -73,-120 -74.5,-120 -76,-120 -77.5,-120 -79,-120 -80.5,-120 -82,-120 -83.5,-120 -85,-124 -85,-128 -85,-132 -85,-136 -85,-140 -85,-144 -85,-148 -85,-152 -85,-156 -85,-160 -85,-160 -83.5,-160 -82,-160 -80.5,-160 -79,-160 -77.5,-160 -76,-160 -74.5,-160 -73,-160 -71.5,-160 -70))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Intellectual Merit: Neogene sediment records recovered by ANDRILL suggest multiple events of open water conditions and elevated sea surface temperatures at times when terrestrial data from the McMurdo Dry Valleys indicate hyper arid, cold, desert conditions. Interpretation of the ANDRILL data suggests the West Antarctic Ice Sheet is highly sensitive to changes in Pliocene sea surface temperatures and this conclusion has been supported by recent Global Circulation Model results for the early to mid Pliocene. The PIs propose to model paleo-ice configurations and warm orbits associated with a WAIS collapse to assess potential climate change in East Antarctica. During such episodes of polar warmth they propose to answer: What is the limit of ablation along the East Antarctic Ice Sheet?; Are relict landforms in the Dry Valleys susceptible to modification from increase in maximum summertime temperatures?; and Is there sufficient increase in minimum wintertime temperatures to sustain a tundra environment in the Dry Valleys? Integration of depositional records and model outputs have the potential to test the performance of numerical models currently under development as part of ANDRILL; reconcile inconsistencies between marine and terrestrial paleoclimate records in high Southern Latitudes; and improve understanding of Antarctic climate and ice volume sensitivity to forcing for both the East Antarctic and West Antarctic Ice Sheets. Broader impacts: Results from this study have the potential to be used widely by the research community. Outreach to local elementary schools from other funded efforts will continue and be extended to homeschooled students. A Post Doc will be supported as part of this award.\n", "east": -120.0, "geometry": ["POINT(-140 -77.5)"], "keywords": "Antarctica; Atmosphere; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Model Data; Paleoclimate; Transantarctic Mountains", "locations": "Antarctica; Transantarctic Mountains", "north": -70.0, "nsf_funding_programs": null, "persons": "Kowalewski, Douglas", "project_titles": "Validating contrasting terrestrial climate-sensitive Pliocene deposits through high resolution modeling of paleo-environments in the Transantarctic Mountains", "projects": [{"proj_uid": "p0000463", "repository": "USAP-DC", "title": "Validating contrasting terrestrial climate-sensitive Pliocene deposits through high resolution modeling of paleo-environments in the Transantarctic Mountains"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -85.0, "title": "Validating contrasting terrestrial climate-sensitive Pliocene deposits through high resolution modeling of paleo-environments in the Transantarctic Mountains", "uid": "600140", "west": -160.0}, {"awards": "1043690 Scherer, Reed", "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, 01 Jan 2014 00:00:00 GMT", "description": "Intellectual Merit: Diatom abundance in sediment cores is typically used as a proxy for paleo primary productivity. This record is complicated by variable preservation, with most loss occurring in the water column via dissolution and zooplankton grazing. This study will investigate preservational biases via a series of controlled experiments to create proxies of original productivity based on morphological changes associated with diatom dissolution and fracture. The PIs will utilize fresh diatoms from culture. Specific objectives include: (1) Linking changes in diatom morphology to availability of dissolved silica and other physical and chemical parameters; (2) Documenting the dissolution process under controlled conditions; (3) Assessment of changes in morphology and diatom surface roughness with increased dissolution; (4) Documenting the physical effects of grazing and fecal pellet formation on diatom fragmentation and dissolution; and (5) Analyzing the impact of diatom dissolution on silica and carbon export. These objectives will be achieved by growing Southern Ocean diatom species in the laboratory under differing physical and chemical conditions; controlled serial dissolution experiments on cultured diatoms; analysis of the dissolution process by imaging frustules under scanning electron microscopy (SEM) and with micro-analysis of surface texture by atomic force microscopy (AFM); making the cultures available to krill and other live zooplankton crustaceans in order to analyze the specific effects of grazing and pelletization on diatom morphology; and comparing experimental results with natural plankton, sediment trap material, and selected Holocene, Pleistocene and Pliocene sediment core material.\nBroader impacts: This work will contribute to understanding of the use of diatom abundance as an indicator of paleoproductivity. The proposed experiments are multi-disciplinary in nature. Importantly, the project was designed, and the proposal largely written, by a Ph.D. candidate. The research proposed here will lead to peer-reviewed publications and provide a base for future studies over the course of an extremely promising scientific career. The project will also support an undergraduate research student at NIU. The PI is heavily involved in science outreach, including classroom visits, museum events and webinars related to evolution and climate change, and is active with NSF-funded outreach activities linked to the ANDRILL and WISSARD programs. He will continue these efforts with this project.", "east": 180.0, "geometry": ["POINT(0 -89.999)"], "keywords": "Antarctica; Biota; Diatom; Marine Sediments; Oceans; Sediment Core; Southern Ocean", "locations": "Antarctica; Southern Ocean", "north": -60.0, "nsf_funding_programs": null, "persons": "Haji-Sheikh, Michael; Scherer, Reed Paul", "project_titles": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export", "projects": [{"proj_uid": "p0000360", "repository": "USAP-DC", "title": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Southern Ocean Diatom Taphonomy and Paleoproductivity: A Laboratory Study of Silica Degradation and Export", "uid": "600127", "west": -180.0}, {"awards": "0944489 Williams, Trevor", "bounds_geometry": ["POLYGON((-55 -58,-33.2 -58,-11.4 -58,10.4 -58,32.2 -58,54 -58,75.8 -58,97.6 -58,119.4 -58,141.2 -58,163 -58,163 -60,163 -62,163 -64,163 -66,163 -68,163 -70,163 -72,163 -74,163 -76,163 -78,141.2 -78,119.4 -78,97.6 -78,75.8 -78,54 -78,32.2 -78,10.4 -78,-11.4 -78,-33.2 -78,-55 -78,-55 -76,-55 -74,-55 -72,-55 -70,-55 -68,-55 -66,-55 -64,-55 -62,-55 -60,-55 -58))"], "date_created": "Wed, 01 Jan 2014 00:00:00 GMT", "description": "Intellectual Merit: The PIs propose to study the stability and dynamics of the East Antarctic ice sheet during the Pliocene in the area of the Wilkes and Aurora subglacial basins. Models indicate the ice sheet is most sensitive to warming in these low-lying areas. This study is important as there is very little direct evidence about which parts of the East Antarctic ice sheet became unstable under warm conditions. In a pilot study the PIs have shown that the isotopic geochemical signature of downcore ice-rafted debris (IRD) can be linked to continental source areas indicating which parts of the ice sheet reached the coast and calved IRD-bearing icebergs. Their initial results suggest rapid iceberg discharge from the Wilkes Land and Adelie Land coastal areas at times in the late Miocene and early Pliocene. In this study the PIs will analyze IRD from IODP sediment cores collected on the continental rise off East Antarctica. By analyzing 40Ar/39Ar ages of hornblende IRD grains, U-Pb ages of zircons, and Sm-Nd isotopes of the fine fraction of several IRD-rich layers for each core, they will be able to fingerprint continental source areas that indicate ice extent and dynamics on East Antarctica. The PIs will also carry out detailed studies across a few of these layers to characterize the anatomy of the ice-rafting event and better understand the mechanism of ice destabilization. Broader impacts: The data collected will be important for scientists in a broad variety of fields. The project will involve one undergraduate student and one summer intern at LDEO, and a graduate student at Imperial College London. The project will expose to cutting edge methodologies as well as an international research team. Data from the project will be deposited in the online databases (SedDB) and all results and methods will be made available to the scientific community through publications in peer-reviewed journals and attendance at international conferences\n", "east": 163.0, "geometry": ["POINT(54 -68)"], "keywords": "Geochronology; George V Land; IODP U1356; IODP U1361; Marine Sediments; ODP1165; Prydz Bay; Solid Earth; Southern Ocean; Wilkes Land", "locations": "Southern Ocean; Wilkes Land; Prydz Bay; George V Land", "north": -58.0, "nsf_funding_programs": null, "persons": "Williams, Trevor; Hemming, Sidney R.", "project_titles": "History of the East Antarctic Ice Sheet since the mid-Miocene: New Evidence from Provenance of Ice-rafted Debris", "projects": [{"proj_uid": "p0000353", "repository": "USAP-DC", "title": "History of the East Antarctic Ice Sheet since the mid-Miocene: New Evidence from Provenance of Ice-rafted Debris"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "History of the East Antarctic Ice Sheet since the mid-Miocene: New Evidence from Provenance of Ice-rafted Debris", "uid": "600116", "west": -55.0}, {"awards": "0739452 Mukhopadhyay, Sujoy", "bounds_geometry": ["POLYGON((161 -76,161.2 -76,161.4 -76,161.6 -76,161.8 -76,162 -76,162.2 -76,162.4 -76,162.6 -76,162.8 -76,163 -76,163 -76.2,163 -76.4,163 -76.6,163 -76.8,163 -77,163 -77.2,163 -77.4,163 -77.6,163 -77.8,163 -78,162.8 -78,162.6 -78,162.4 -78,162.2 -78,162 -78,161.8 -78,161.6 -78,161.4 -78,161.2 -78,161 -78,161 -77.8,161 -77.6,161 -77.4,161 -77.2,161 -77,161 -76.8,161 -76.6,161 -76.4,161 -76.2,161 -76))"], "date_created": "Thu, 01 Jan 2009 00:00:00 GMT", "description": "This project seeks to answer a simple question: how old are potholes and related geomorphic features found in the uplands of the McMurdo Dry Valleys, Antarctica? Some research suggests that they are over ten million years old and date the growth of the East Antarctic Ice Sheet, the world\u0027s largest. However, some evidence suggests that these are young, erosional features that continuing to evolve to this day. This project uses cosmogenic nuclide dating to determine the age of the pothole floors. The results are important for determining the ice sheet?s history and interpreting the O-isotope record from the marine sediment cores, key records of global climate. Broader impacts include K12 outreach and incorporation of outcomes into university courses.", "east": 163.0, "geometry": ["POINT(162 -77)"], "keywords": "Antarctica; Cosmogenic Dating; Dry Valleys; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Paleoclimate; Sample/collection Description; Sample/Collection Description; Solid Earth", "locations": "Dry Valleys; Antarctica", "north": -76.0, "nsf_funding_programs": null, "persons": "Mukhopadhyay, Sujoy", "project_titles": "Landform Evolution in the Dry Valleys and its implications for Miocene-Pliocene Climate Change in Antarctica", "projects": [{"proj_uid": "p0000461", "repository": "USAP-DC", "title": "Landform Evolution in the Dry Valleys and its implications for Miocene-Pliocene Climate Change in Antarctica"}], "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Landform Evolution in the Dry Valleys and its implications for Miocene-Pliocene Climate Change in Antarctica", "uid": "600074", "west": 161.0}]

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