USAP-DC

{"dp_type": "Project", "free_text": "MINERALS"}

[{"awards": "2420219 Chignell, Stephen", "bounds_geometry": "POLYGON((160 -76.5,160.45 -76.5,160.9 -76.5,161.35 -76.5,161.8 -76.5,162.25 -76.5,162.7 -76.5,163.15 -76.5,163.6 -76.5,164.05 -76.5,164.5 -76.5,164.5 -76.7,164.5 -76.9,164.5 -77.1,164.5 -77.3,164.5 -77.5,164.5 -77.7,164.5 -77.9,164.5 -78.1,164.5 -78.3,164.5 -78.5,164.05 -78.5,163.6 -78.5,163.15 -78.5,162.7 -78.5,162.25 -78.5,161.8 -78.5,161.35 -78.5,160.9 -78.5,160.45 -78.5,160 -78.5,160 -78.3,160 -78.1,160 -77.9,160 -77.7,160 -77.5,160 -77.3,160 -77.1,160 -76.9,160 -76.7,160 -76.5))", "dataset_titles": null, "datasets": null, "date_created": "Tue, 13 Aug 2024 00:00:00 GMT", "description": "Geodiversity is the variety of non-living elements like rocks, landforms, and processes in a given area, and plays an especially critical role in Antarctica. Geodiversity provides the conditions in which life can develop and underpins all ecosystems on Earth. It also provides tangible services to people (like construction materials) as well as intangible benefits (such as scientific knowledge from ice cores and artistic inspiration from glaciers). Despite its importance, Antarctic geodiversity remains under-explored, under-described, and inadequately mapped. This knowledge gap is particularly concerning given the threats posed by increasing human activity and environmental and climate change. This project uses a variety of datasets to map Antarctic geodiversity, assess its benefits to people, and help identify priority locations for conservation. Through an interdisciplinary and mixed-method approach, this research will fill a major gap in the current understanding and representations of the Antarctic. Using the McMurdo Dry Valleys as a case study, the researcher will combine geospatial data on geology, geomorphology, pedology, and hydrology to map geodiversity of the region. This project will identify sites of key geosystem services by analyzing geospatial data on placenames, scientific samples, and a web-based participatory mapping survey. The geodiversity and geosystem services data will then be overlaid and combined to identify hotspots of geo-social diversity. The resulting maps will be compared with the region\u0027s protected area boundaries to assess the fit-for-purpose of current environmental management and identify priority locations for future research and conservation. The fellow will promote Antarctic geodiversity broadly, including at UNESCO International Geodiversity Day. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 164.5, "geometry": "POINT(162.25 -77.5)", "instruments": null, "is_usap_dc": true, "keywords": "McMurdo Dry Valleys; LANDSCAPE; ROCKS/MINERALS/CRYSTALS; LANDFORMS; GIS; GLACIAL LANDFORMS; RIVERS/STREAMS", "locations": "McMurdo Dry Valleys", "north": -76.5, "nsf_funding_programs": "Antarctic Organisms and Ecosystems", "paleo_time": null, "persons": "Chignell, Stephen", "platforms": null, "repositories": null, "science_programs": null, "south": -78.5, "title": "Postdoctoral Fellowship: OPP-PRF: Mapping Antarctic Geodiversity: Assessing People, Place, and Abiotic Nature in the McMurdo Dry Valleys", "uid": "p0010476", "west": 160.0}, {"awards": "2336354 Juarez Rivera, Marisol", "bounds_geometry": "POLYGON((160 -76.5,160.45 -76.5,160.9 -76.5,161.35 -76.5,161.8 -76.5,162.25 -76.5,162.7 -76.5,163.15 -76.5,163.6 -76.5,164.05 -76.5,164.5 -76.5,164.5 -76.7,164.5 -76.9,164.5 -77.1,164.5 -77.3,164.5 -77.5,164.5 -77.7,164.5 -77.9,164.5 -78.1,164.5 -78.3,164.5 -78.5,164.05 -78.5,163.6 -78.5,163.15 -78.5,162.7 -78.5,162.25 -78.5,161.8 -78.5,161.35 -78.5,160.9 -78.5,160.45 -78.5,160 -78.5,160 -78.3,160 -78.1,160 -77.9,160 -77.7,160 -77.5,160 -77.3,160 -77.1,160 -76.9,160 -76.7,160 -76.5))", "dataset_titles": "Lake Fryxell 2022-2023 benthic microbial mat thickness and number of laminae", "datasets": [{"dataset_uid": "601839", "doi": "10.15784/601839", "keywords": "Antarctica; Cryosphere; Dry Valleys; Lake Fryxell; Laminae; Microbial Mat; Thickness", "people": "Sumner, Dawn; Paul, Ann; Hawes, Ian; Mackey, Tyler; Juarez Rivera, Marisol", "repository": "USAP-DC", "science_program": null, "title": "Lake Fryxell 2022-2023 benthic microbial mat thickness and number of laminae", "url": "https://www.usap-dc.org/view/dataset/601839"}], "date_created": "Fri, 05 Jul 2024 00:00:00 GMT", "description": "Perennially ice-covered lakes in the McMurdo Dry Valleys of Antarctica contain abundant microbial mats, and the export of this mat material can fertilize the surrounding polar desert ecosystems. These desert soils are one of the most organic-poor on earth yet host a community of microorganisms. Microbial mat material is exported from the shallow, gas-supersaturated regions of the lakes when gas bubbles form in the mats, lifting them to the ice cover; the perennial ice cover maintains gas supersaturation. These mats freeze in and are exported to the surrounding soils through ice ablation. The largest seasonal decrease and thinnest ice cover in the history of Lake Fryxell was recorded during the 2022-2023 Austral summer. In this thin ice year, the water column dissolved oxygen increased over prior observations, and the lake bottom surface area with bubble-disrupted mat was more than double that observed in 1980-1981 and 2006-2007. This work will constrain mat mobilization within and out of Lake Fryxell in the McMurdo Dry Valleys during a period of unprecedented ice thinning to understand how future changing regional climate and predicted seasonal loss of lake ice cover will affect nutrient transport in the McMurdo Dry Valleys. Exceptional years of mat export are hypothesized to have the most significant impact on nutrient export to soil communities; variability in mat liftoff may thus play a role in the McMurdo Dry Valleys ecosystem response to changing climate. The perennial ice cover of lakes in the McMurdo Dry Valleys of Antarctica modulates the transfer of gasses, organic and inorganic material, between the lakes and surrounding soils. The export of biomass in these lakes is driven by the supersaturation of atmospheric gasses in the shallow regions under perennial ice cover. Gas bubbles nucleate in the mats, producing buoyancy that lifts them to the bottom of the ice, where they freeze in and are exported to the surrounding soils through ice ablation. These mats represent a significant source of biomass and nutrients to the McMurdo Dry Valleys soils, which are among the most organic-poor on earth. Nevertheless, this biomass remains unaccounted for in organic carbon cycling models for the McMurdo Dry Valleys. Ice cover data from the McMurdo Dry Valleys Long Term Ecological Research Project shows that the ice thickness has undergone cyclical variation over the last 40 years, reaching the largest seasonal decrease and thinnest ice-cover in the recorded history of Lake Fryxell during the 2022-2023 austral summer. Preliminary work shows that the surface area with mat liftoff at Lake Fryxell is more than double that observed in 1980-1981 and 2006-2007, coinciding with this unprecedented thinning of the ice-cover and an increase in the water column dissolved O2. This research will constrain biomass mobilization within and out of Lake Fryxell in the McMurdo Dry Valleys during a period of unprecedented ice thinning. The researchers hypothesize that a thinner ice cover promotes more biomass mobilization by 1) stimulating additional production of gas bubbles from the existing gas-supersaturated waters during summertime photosynthesis to create microbial mat liftoff and 2) promoting mat liftoff in deeper, thicker microbial mats, and 3) that this biomass can be traced into the soils by characterizing its chemistry and modeling the most likely depositional settings. This work will use microbial mat samples, lake dissolved oxygen and photosynthetically active radiation data and underwater drone footage documenting the depth distribution of liftoff mats in January 2023, and long-term ice cover thickness, photosynthetically active radiation, and lake level change data collected by the McMurdo Dry Valleys Long Term Ecological Research Project to test hypotheses 1-3. The dispersal of the liftoff mat exposed at Lake Fryxell surface will be modeled using a Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Exceptional liftoff years like the present are hypothesized to have the most significant impact on the soil communities as the rates of soil respiration increase with the addition of carbon. However, continued warming in the next 10 - 40 years may result in seasonal loss of the ice cover and cessation of liftoff mat export. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 164.5, "geometry": "POINT(162.25 -77.5)", "instruments": null, "is_usap_dc": true, "keywords": "Stable Isotopes; MINERALS; LAKE/POND; ISOTOPES; Organic Matter; McMurdo Dry Valleys; SEDIMENTARY ROCKS", "locations": "McMurdo Dry Valleys", "north": -76.5, "nsf_funding_programs": "Antarctic Organisms and Ecosystems; Antarctic Earth Sciences", "paleo_time": null, "persons": "Juarez Rivera, Marisol", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.5, "title": "RAPID: Is Biomass Mobilization at Ice-covered Lake Fryxell, Antarctica reaching a Critical Threshold?", "uid": "p0010467", "west": 160.0}, {"awards": "2423761 Blackburn, Terrence", "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))", "dataset_titles": "Thermogenic Methane Production in Antarctic Subglacial Hydrocarbon Seeps", "datasets": [{"dataset_uid": "601918", "doi": "10.15784/601918", "keywords": "Antarctica; Carbon Isotopes; Cryosphere; East Antarctica; Elephant Moraine; Geochronology; Isotope Data; Subglacial", "people": "Piccione, Gavin", "repository": "USAP-DC", "science_program": null, "title": "Thermogenic Methane Production in Antarctic Subglacial Hydrocarbon Seeps", "url": "https://www.usap-dc.org/view/dataset/601918"}], "date_created": "Tue, 14 May 2024 00:00:00 GMT", "description": "Non-technical abstract Earth\u2019s climatic changes have been recorded in the ice core collected from the Antarctic ice sheet. While these records provide a high resolution view of how polar temperatures changed through time, it is not always clear what Earth process influence Antarctic climate. One likely contributor to Antarctic temperature changes is the cyclic changes in Earth\u2019s orientation as it orbits the sun. These so-called Milankovitch cycles control the amount and pattern of sunlight reaching the polar regions, that in turn result in periods of climatic warming or cooling. While the orbital variations and control on incoming solar energy remain well understood, how they influence Antarctic climate remains unresolved. It is the goal of this project to determine how variations in Earth\u2019s orbit may be locally influencing Antarctic temperatures. The researchers on this project are pursing this goal by identifying periods of past ice melting on the surface of Antarctica using minerals that precipitate from the meltwaters that resulted from past warm periods. The timing of this past melting will be determined by radioisotopic dating of the minerals using the natural radioactive decay of uranium to thorium. By dating numerous samples, collected in past scientific expeditions throughout the Antarctic continent, these researchers aim to reconstruct the frequency and spatial pattern of past warming and in doing so, determine what aspect of Earth\u2019s orbital variations influences Antarctic ice loss. Technical abstract Antarctic ice cores provide high resolution records of Pleistocene Southern Hemisphere temperatures that show an overall coherence with Northern Hemisphere temperature variations. One explanation for this bi-hemispheric temperature covariance relies on changes in atmospheric CO2 that result from varying northern hemisphere insolation. An alternative posits that the apparent coherence of polar temperatures is due to the misleading covariance between northern hemisphere summer insolation and, the southern hemisphere summer duration. At present there is an insufficient understanding of the role that local insolation plays in Antarctic climate. The goal of this research project is to identify the temporal spatial patterns of solar forcing in Antarctica. To reach this goal, the project team will: 1) develop a way to identify periods of past surface melt production in Antarctica using U-Th dating of pedogenic carbonates; and 2) utilize the evidence of past surface melting to calibrate energy balance models and interrogate past Antarctic surface temperatures and; 3) compare the timing of Antarctic warm periods to potential solar forcing mechanisms such as peak summer insolation or summer duration. A means of identifying the spatial and temporal pattern at which local insolation influences Antarctic temperature would provide a transformative solution to the contradiction in current climate records. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "Antarctic Ice Sheet; PALEOCLIMATE RECONSTRUCTIONS", "locations": "Antarctic Ice Sheet", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Blackburn, Terrence", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "EAGER: Pedogenic Carbonates Record Insolation Driven Surface Melting in Antarctica", "uid": "p0010459", "west": -180.0}, {"awards": "2317263 Cross, Andrew", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Mon, 14 Aug 2023 00:00:00 GMT", "description": "The seaward motion of ice sheets and glaciers is primarily controlled by basal sliding at the base of the ice sheet and internal viscous flow within the ice mass. The latter of these \u2014 viscous flow \u2014 is dependent on various factors, including temperature, stress, grain size, and the alignment of ice crystals during flow to produce a \"crystal orientation fabric\" (COF). Historically, ice flow has been modeled using an equation, termed \u201cGlen\u2019s law\u201d, that describes ice-flow rate as a function of temperature and stress. Glen\u2019s law was constrained under relatively high-stress conditions and is often attributed to the motion of crystal defects within ice grains. More recently, however, grain boundary sliding (GBS) has been invoked as the rate-controlling process under low-stress, \u201csuperplastic\u201d conditions. The grain boundary sliding hypothesis is contentious because GBS is not thought to produce a COF, whereas geophysical measurements and polar ice cores demonstrate strong COFs in polar ice masses. However, very few COF measurements have been conducted on ice samples subjected to superplastic flow conditions in the laboratory. This project would measure the evolution of ice COF across the transition from superplastic to Glen-type creep. Results will be used to interrogate the role of superplastic GBS creep within polar ice masses, and thereby provide constraints on polar ice discharge models. Polycrystalline ice samples with grain sizes ranging from 5 \u00b5m to 1000 \u00b5m will be fabricated and deformed in a laboratory, using a 1-atm cryogenic axial-torsion apparatus. Experiments will be conducted at temperatures of -30\u00b0C to -10\u00b0C, and at a constant uniaxial strain rate. Under these conditions, 5% to 99.99% of strain should be accommodated by superplastic, GBS-limited creep, depending on the sample grain size. The deformed samples will then be imaged using cryogenic electron backscatter diffraction (cryo-EBSD) and high-angular-resolution electron backscatter diffraction (HR-EBSD) to quantify COF, grain size, grain shape, and crystal defect (dislocation) densities, among other microstructural properties. These measurements will be used to decipher the rate-controlling mechanisms operating within different thermomechanical regimes, and resolve a long-standing debate over whether superplastic creep can produce a COF in ice. In addition to the polycrystal experiments, ice bicrystals will be fabricated and deformed to investigate the micromechanical behavior of individual grain boundaries under superplastic conditions. Ultimately, these results will be used to provide a microstructural toolbox for identifying superplastic creep using geophysical (e.g., seismic, radar) and glaciological (e.g., ice core) observations. This project will support one graduate student, one or more undergraduate summer students, and an early-career researcher. In addition, this project will support a workshop aimed at bringing together experimentalists, glaciologists, and ice modelers to facilitate cross-disciplinary knowledge sharing and collaborative problem solving. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "United States Of America; Rheology; ROCKS/MINERALS/CRYSTALS; GLACIERS/ICE SHEETS", "locations": "United States Of America", "north": null, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Cross, Andrew", "platforms": null, "repositories": null, "science_programs": null, "south": null, "title": "Microstructural Evolution during Superplastic Ice Creep", "uid": "p0010430", "west": null}, {"awards": "1917176 Siddoway, Christine; 1916982 Teyssier, Christian; 1917009 Thomson, Stuart", "bounds_geometry": "POLYGON((-160.16 -67.15,-154.572 -67.15,-148.984 -67.15,-143.39600000000002 -67.15,-137.808 -67.15,-132.22 -67.15,-126.632 -67.15,-121.04400000000001 -67.15,-115.456 -67.15,-109.868 -67.15,-104.28 -67.15,-104.28 -68.165,-104.28 -69.18,-104.28 -70.19500000000001,-104.28 -71.21000000000001,-104.28 -72.225,-104.28 -73.24,-104.28 -74.255,-104.28 -75.27,-104.28 -76.285,-104.28 -77.3,-109.868 -77.3,-115.456 -77.3,-121.044 -77.3,-126.632 -77.3,-132.22 -77.3,-137.808 -77.3,-143.396 -77.3,-148.98399999999998 -77.3,-154.572 -77.3,-160.16 -77.3,-160.16 -76.285,-160.16 -75.27,-160.16 -74.255,-160.16 -73.24,-160.16 -72.225,-160.16 -71.21000000000001,-160.16 -70.19500000000001,-160.16 -69.18,-160.16 -68.165,-160.16 -67.15))", "dataset_titles": "Apatite Fission Track Data Marie Byrd Land; Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock; Byrd Ice Core Apatite Fission Track and Zircon U-Pb Data; Low Temperature Thermochronology and Geochronology Data from Sif Island Antarctica; U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "datasets": [{"dataset_uid": "200332", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "U-Pb detrital zircon geochronological data, obtained by LA-ICP-MS", "url": ""}, {"dataset_uid": "200333", "doi": "", "keywords": null, "people": null, "repository": "in progress", "science_program": null, "title": "Apatite fission track thermochronology data for detrital minerals, offshore clasts, and bedrock", "url": ""}, {"dataset_uid": "601944", "doi": "10.15784/601944", "keywords": "Antarctica; Cryosphere; Fission Track Thermochronology; Marie Byrd Land; West Antarctic Ice Sheet", "people": "Thomson, Stuart", "repository": "USAP-DC", "science_program": null, "title": "Apatite Fission Track Data Marie Byrd Land", "url": "https://www.usap-dc.org/view/dataset/601944"}, {"dataset_uid": "601941", "doi": "10.15784/601941", "keywords": "Amundsen Sea; Amundsen Sea Sector; Antarctica; Cryosphere; Fission Track Thermochronology; Thwaites Glacier", "people": "Thomson, Stuart", "repository": "USAP-DC", "science_program": null, "title": "Low Temperature Thermochronology and Geochronology Data from Sif Island Antarctica", "url": "https://www.usap-dc.org/view/dataset/601941"}, {"dataset_uid": "601940", "doi": "10.15784/601940", "keywords": "Antarctica; Byrd Ice Core; Cryosphere; Fission Track Thermochronology; Marie Byrd Land; West Antarctic Ice Sheet", "people": "Thomson, Stuart", "repository": "USAP-DC", "science_program": "Byrd Ice Core", "title": "Byrd Ice Core Apatite Fission Track and Zircon U-Pb Data", "url": "https://www.usap-dc.org/view/dataset/601940"}], "date_created": "Wed, 19 Oct 2022 00:00:00 GMT", "description": "Sediment records off the coast of Marie Byrd Land (MBL), Antarctica suggest frequent and dramatic changes in the size of the West Antarctic Ice Sheet (WAIS) over short (tens of thousands of years) and long (millions of years) time frames in the past. WAIS currently overrides much of MBL and covers the rugged and scoured bedrock landscape. The ice sheet carved narrow linear troughs that reach depths of two to three thousand meters below sea level as outlet glaciers flowed from the interior of the continent to the oceans. As a result, large volumes of fragmented continental bedrock were carried out to the seabed. The glaciers cut downward into a region of crystalline rocks (i.e. granite) whose temperature change as a function of rock depth happens to be significant. This strong geothermal gradient in the bedrock is favorable for determining when the bedrock experienced rapid exhumation or \"uncovering\". Analyzing the chemistry of minerals (zircon and apatite) within the eroded rocks will provide information about the rate and timing of the glacier removal of bedrock from the Antarctic continent. The research addresses the following questions: When did the land become high enough for a large ice sheet to form? What was the regional pre-glacial topography? Under what climate conditions, and at what point in the growth of an ice sheet, did glaciers begin to cut sharply into bedrock to form the narrow troughs that flow seaward? The research will lead to greater understanding of past Antarctic ice sheet fluctuations and identify precise timing of glacial incision. These results will refine ice sheet history and aid the international societal response to contemporary ice sheet change and its global consequences. The project will contribute to the training of two graduate and two undergraduate students in STEM. The objective is to clarify the onset of WAIS glacier incision and assess the evolution of Cenozoic paleo-topography. Low-temperature (T) thermochronology and Pecube 3-D thermo-kinematic modeling will be applied to date and characterize episodes of glacial erosional incision. Single-grain double- and triple-dating of zircon and apatite will reveal the detailed crustal thermal evolution of the region enabling the research team to determine the comparative topographic influences on glaciation versus bedrock uplift induced by Eocene to present tectonism/magmatism. High-T mineral thermochronometers across Marie Byrd Land (MBL) record rapid extension-related cooling at ~100 Ma from temperatures of \u003e800 degrees C to \u0026#8804; 300 degrees C. This signature forms a reference horizon, or paleogeotherm, through which the Cenozoic landscape history using low-T thermochronometers can be explored. MBL\u0027s elevated geothermal gradient, sustained during the Cenozoic, created favorable conditions for sensitive apatite and zircon low-T thermochronometers to record bedrock cooling related to glacial incision. Students will be trained to use state-of-the-art analytical facilities in Arizona and Minnesota, expanding the geo- and thermochronologic history of MBL from bedrock samples and offshore sedimentary deposits. The temperature and time data they acquire will provide constraints on paleotopography, isostasy, and the thermal evolution of MBL that will be modeled in 3D using Pecube model simulations. Within hot crust, less incision is required to expose bedrock containing the distinct thermochronometric profile; a prediction that will be tested with inverse Pecube 3-D models of the thermal field through which bedrock and detrital samples cooled. Using results from Pecube, the ICI-Hot team will examine time-varying topography formed in response to changes in erosion rates, topographic relief, geothermal gradient and/or flexural isostatic rigidity. These effects are manifestations of dynamic processes in the WAIS, including ice sheet loading, ice volume fluctuations, relative motion upon crustal faults, and magmatism-related elevation increase across the MBL dome. The project makes use of pre-existing sample collections housed at the US Polar Rock Repository, IODP\u0027s Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -104.28, "geometry": "POINT(-132.22 -72.225)", "instruments": null, "is_usap_dc": true, "keywords": "Marie Byrd Land; GLACIERS/ICE SHEETS; Zircon; Subglacial Topography; FIELD SURVEYS; TECTONICS; Ice Sheet; Thermochronology; Apatite; ROCKS/MINERALS/CRYSTALS; Erosion; United States Of America; LABORATORY", "locations": "United States Of America; Marie Byrd Land", "north": -67.15, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": "PHANEROZOIC", "persons": "Siddoway, Christine; Thomson, Stuart; Teyssier, Christian", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "in progress", "repositories": "in progress; USAP-DC", "science_programs": null, "south": -77.3, "title": "Collaborative Research: Ice sheet erosional interaction with hot geotherm in West Antarctica", "uid": "p0010386", "west": -160.16}, {"awards": "1744771 Balco, Gregory", "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))", "dataset_titles": "5 million year transient Antarctic ice sheet model run with \"desensitized\" marine ice margin instabilities; 5 million year transient Antarctic ice sheet model run with \"sensitized\" marine ice margin instabilities", "datasets": [{"dataset_uid": "601601", "doi": "10.15784/601601", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Sheet Modeling; Marine Ice Margin Instability; Model Output", "people": "Halberstadt, Anna Ruth; Buchband, Hannah; Balco, Gregory", "repository": "USAP-DC", "science_program": null, "title": "5 million year transient Antarctic ice sheet model run with \"desensitized\" marine ice margin instabilities", "url": "https://www.usap-dc.org/view/dataset/601601"}, {"dataset_uid": "601602", "doi": "10.15784/601602", "keywords": "Antarctica; Glaciers/ice Sheet; Glaciers/Ice Sheet; Glaciology; Ice Sheet Modeling; Marine Ice Margin Instability; Model Output", "people": "Balco, Gregory; Buchband, Hannah; Halberstadt, Anna Ruth", "repository": "USAP-DC", "science_program": null, "title": "5 million year transient Antarctic ice sheet model run with \"sensitized\" marine ice margin instabilities", "url": "https://www.usap-dc.org/view/dataset/601602"}], "date_created": "Tue, 21 Jun 2022 00:00:00 GMT", "description": "The purpose of this project is to use geological data that record past changes in the Antarctic ice sheets to test computer models for ice sheet change. The geologic data mainly consist of dated glacial deposits that are preserved above the level of the present ice sheet, and range in age from thousands to millions of years old. These provide information about the size, thickness, and rate of change of the ice sheets during past times when the ice sheets were larger than present. In addition, some of these data are from below the present ice surface and therefore also provide some information about past warm periods when ice sheets were most likely smaller than present. The primary purpose of the computer model is to predict future ice sheet changes, but because significant changes in the size of ice sheets are slow and likely occur over hundreds of years or longer, the only way to determine whether these models are accurate is to test their ability to reproduce past ice sheet changes. The primary purpose of this project is to carry out such a test. The research team will compile relevant geologic data, in some cases generate new data by dating additional deposits, and develop methods and software to compare data to model simulations. In addition, this project will (i) contribute to building and sustaining U.S. science capacity through postdoctoral training in geochronology, ice sheet modeling, and data science, and (ii) improve public access to geologic data and model simulations relevant to ice sheet change through online database and website development. Technical aspects of this project are primarily focused on the field of cosmogenic-nuclide exposure-dating, which is a method that relies on the production of rare stable and radio-nuclides by cosmic-ray interactions with rocks and minerals exposed at the Earth\u0027s surface. Because the advance and retreat of ice sheets results in alternating cosmic-ray exposure and shielding of underlying bedrock and surficial deposits, this technique is commonly used to date and reconstruct past ice sheet changes. First, this project will contribute to compiling and systematizing a large amount of cosmogenic-nuclide exposure age data collected in Antarctica during the past three decades. Second, it will generate additional geochemical data needed to improve the extent and usefulness of measurements of stable cosmogenic nuclides, cosmogenic neon-21 in particular, that are useful for constraining ice-sheet behavior on million-year timescales. Third, it will develop a computational framework for comparison of the geologic data set with existing numerical model simulations of Antarctic ice sheet change during the past several million years, with particular emphasis on model simulations of past warm periods, for example the middle Pliocene ca. 3-3.3 million years ago, during which the Antarctic ice sheets are hypothesized to have been substantially smaller than present. Fourth, guided by the results of this comparison, it will generate new model simulations aimed at improving agreement between model simulations and geologic data, as well as diagnosing which processes or parameterizations in the models are or are not well constrained by the data. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "BERYLLIUM-10 ANALYSIS; AMD; ICE SHEETS; GLACIATION; Amd/Us; LABORATORY; USA/NSF; Antarctica; ALUMINUM-26 ANALYSIS; USAP-DC", "locations": "Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Glaciology", "paleo_time": null, "persons": "Balco, Gregory", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Synoptic Evaluation of Long-Term Antarctic Ice Sheet Model Simulations using a Continent-Wide Database of Cosmogenic-Nuclide Measurements", "uid": "p0010342", "west": -180.0}, {"awards": "2139497 Balco, Gregory", "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))", "dataset_titles": null, "datasets": null, "date_created": "Tue, 21 Jun 2022 00:00:00 GMT", "description": "This project will conduct basic research into geological dating techniques that are useful for determining the age of glacial deposits in polar regions, Antarctica in particular. These techniques are necessary for determining how large the polar ice sheets were in the geologic past, including during past periods of warm climate that likely resemble present and near-future conditions. Thus, they represent an important technical capability needed for estimating the response of polar ice sheets to climate warming. Because changes in the size of polar ice sheets are the largest potential contribution to future global sea-level change, this capability is also relevant to understanding likely sea-level impacts of future climate change. The research in this project comprises several observational and experimental approaches to improving the speed, efficiency, cost, and accuracy of these techniques, as well as a scientific outreach program aimed at making the resulting capabilities more broadly available to other researchers. The project supports a postdoctoral scholar and contributes to human resources development in polar and climate science. The project focuses on several areas of cosmogenic-nuclide geochemistry, which is a geochemical dating method that relies on the production and decay of cosmic-ray-produced radionuclides in surface rocks. Measurements of these nuclides can be used to quantify the duration of surface exposure and ice cover at locations in Antarctica that are covered and uncovered by changes in the size of the Antarctic ice sheets, thus providing a means of reconstructing past ice-sheet change. The first proposed set of experiments are aimed at implementing a \u0027virtual mineral separation\u0027 approach to cosmogenic noble gas analysis that may allow measurement of nuclide concentrations in certain minerals without physically separating the minerals from the host rock. If feasible, this would realize significant speed and cost improvements for this type of analysis. A second set of experiments will focus on means of identifying and quantifying non-cosmogenic background inventories of some relevant nuclides, which is intended to improve the measurement sensitivity and precision for cosmic-ray-produced inventories of these nuclides. A third focus area aims to improve capabilities to measure multiple cosmic-ray-produced nuclides in the same sample, which has the potential to improve the accuracy of dating methods based on these nuclides and to expand the situations in which these methods can be applied. If successful, these experiments are likely to improve a number of applications of cosmogenic-nuclide geochemistry relevant to Antarctic research, including subglacial bedrock exposure dating, dating of multimillion-year-old glacial deposits, and surface-process studies useful in understanding landform evolution and ecosystem dynamics. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "California; LABORATORY; AMD; GEOCHEMISTRY; Amd/Us; USAP-DC; USA/NSF", "locations": "California", "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Earth Sciences", "paleo_time": null, "persons": "Balco, Gregory", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": -90.0, "title": "Targeted Basic Research to Enable Antarctic Science Applications of Cosmogenic-Nuclide Geochemistry", "uid": "p0010343", "west": -180.0}, {"awards": "1643713 Grunow, Anne; 9910267 Grunow, Anne; 2137467 Grunow, Anne; 1141906 Grunow, Anne; 2436582 Grunow, Anne; 0440695 Grunow, Anne; 0739480 Grunow, Anne", "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))", "dataset_titles": "Marine Geoscience Data System - cruise links; Polar Rock Repository; SESAR sample registration", "datasets": [{"dataset_uid": "200243", "doi": "", "keywords": null, "people": null, "repository": "PRR", "science_program": null, "title": "Polar Rock Repository", "url": "https://prr.osu.edu/"}, {"dataset_uid": "200241", "doi": "", "keywords": null, "people": null, "repository": "SESAR", "science_program": null, "title": "SESAR sample registration", "url": "https://www.geosamples.org/about/services#igsnregistration"}, {"dataset_uid": "200242", "doi": "", "keywords": null, "people": null, "repository": "MGDS", "science_program": null, "title": "Marine Geoscience Data System - cruise links", "url": "https://www.marine-geo.org/"}, {"dataset_uid": "200359", "doi": "", "keywords": null, "people": null, "repository": "PRR", "science_program": null, "title": "Polar Rock Repository", "url": "http://research.bpcrc.osu.edu/rr/"}], "date_created": "Thu, 09 Sep 2021 00:00:00 GMT", "description": "Non-Technical Abstract: The Polar Rock Repository (PRR) at The Ohio State University provides a unique resource for researchers studying the polar regions by offering free access to geological samples and data. This project seeks support to continue expanding and managing the collection, which is vital for scientific studies and planning fieldwork in Antarctica. Over the next five years, the repository plans to add tens of thousands of new samples and images, making it easier for researchers to study polar geology without the high cost and environmental impact of traveling to remote Antarctic locations. The PRR also supports education and outreach by providing hands-on resources for schools, colleges, and the public, including a \"Polar Rock Box\" program that brings real Antarctic samples into classrooms. This work ensures the preservation of important scientific materials and makes them accessible to a broad community, advancing understanding of our planet\u2019s polar regions. Technical Abstract: The Polar Rock Repository (PRR) at The Ohio State University serves as a critical resource for polar earth science research, offering no-cost loans of geological samples and comprehensive metadata to the scientific community. This proposal seeks funding to support the continued curation, expansion, and management of the PRR, alongside its educational and outreach initiatives. Over the next five years, the PRR anticipates acquiring approximately 15,000 new samples, including those from major drilling operations (RAID, Winkie drill cores) and polar cruises. The repository also aims to significantly grow its archives of images, petrographic thin sections, and mineral separates. By preserving these physical and digital assets in a discoverable online database, the PRR fosters transparency, reproducibility, and accessibility in polar research, fulfilling Antarctic data management mandates. The intellectual merit lies in enabling cutting-edge scientific analyses through freely available samples and metadata. Broader impacts include reduced environmental costs of Antarctic research, enhanced educational opportunities, and outreach to a diverse audience through initiatives like the \"Polar Rock Box\" program. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "USAP-DC; FIELD SURVEYS; Pacific Ocean; ROCKS/MINERALS/CRYSTALS; GLACIATION; AMD; Weddell Sea; Scotia Sea; TECTONICS; Antarctica; Southern Ocean; Amd/Us; USA/NSF; Amundsen Sea", "locations": "Pacific Ocean; Amundsen Sea; Scotia Sea; Weddell Sea; Antarctica; Southern Ocean", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Grunow, Anne", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "PRR", "repositories": "MGDS; PRR; SESAR", "science_programs": null, "south": -90.0, "title": "Continuing Operations Proposal: \r\nThe Polar Rock Repository as a Resource for Earth Systems Science\r\n", "uid": "p0010259", "west": -180.0}, {"awards": "1542936 Goehring, Brent; 1542976 Balco, Gregory", "bounds_geometry": "POLYGON((-145.7 -64.195,-113.988 -64.195,-82.276 -64.195,-50.564 -64.195,-18.852 -64.195,12.86 -64.195,44.572 -64.195,76.284 -64.195,107.996 -64.195,139.708 -64.195,171.42 -64.195,171.42 -66.2096,171.42 -68.2242,171.42 -70.2388,171.42 -72.2534,171.42 -74.268,171.42 -76.2826,171.42 -78.2972,171.42 -80.3118,171.42 -82.3264,171.42 -84.341,139.708 -84.341,107.996 -84.341,76.284 -84.341,44.572 -84.341,12.86 -84.341,-18.852 -84.341,-50.564 -84.341,-82.276 -84.341,-113.988 -84.341,-145.7 -84.341,-145.7 -82.3264,-145.7 -80.3118,-145.7 -78.2972,-145.7 -76.2826,-145.7 -74.268,-145.7 -72.2534,-145.7 -70.2388,-145.7 -68.2242,-145.7 -66.2096,-145.7 -64.195))", "dataset_titles": "Interface for viewing observational data related to exposure ages measurements and calculated geologic ages derived therefrom", "datasets": [{"dataset_uid": "200199", "doi": "", "keywords": null, "people": null, "repository": "ICE-D", "science_program": null, "title": "Interface for viewing observational data related to exposure ages measurements and calculated geologic ages derived therefrom", "url": "https://version2.ice-d.org/antarctica/nsf/"}], "date_created": "Fri, 03 Sep 2021 00:00:00 GMT", "description": "The overall goal of this project is to determine the effect of past changes in the size of the Antarctic Ice Sheet on global sea level. At the peak of the last ice age 25,000 years ago, sea level was 120 meters (400 feet) lower than it is at present because water that is now part of the ocean was instead part of expanded glaciers and ice sheets in North America, Eurasia, and Antarctica. Between then and now, melting and retreat of this land ice caused sea level to rise. In this project, we aim to improve our understanding of how changes in the size of the Antarctic Ice Sheet contributed to this process. The overall strategy to accomplish this involves (i) visiting areas in Antarctica that are not now covered by ice; (ii) looking for geological evidence, specifically rock surface and sediment deposits, that indicates that these areas were covered by thicker ice in the past; and (iii) determining the age of these geological surfaces and deposits. This project addresses the final part of this strategy -- determining the age of Antarctic glacial rock surfaces or sediment deposits -- using a relatively new technique that involves measuring trace elements in rock surfaces that are produced by cosmic-ray bombardment after the rock surfaces are exposed by ice retreat. By applying this method to rock samples collected in previous visits to Antarctica, the timing of past expansion and contraction of the ice sheet can be determined. The main scientific outcomes expected from this project are (i) improved understanding of how Antarctic Ice Sheet changes contributed to past global sea level rise; and (ii) improved understanding of modern observed Antarctic Ice Sheet changes in a longer-term context. This second outcome will potentially improve predictions of future ice sheet behavior. Other outcomes of the project include training of individual undergraduate and graduate students, as well as the development of a new course on sea level change to be taught at Tulane University in New Orleans, a city that is being affected by sea level change today. This project will use measurements of in-situ-produced cosmogenic carbon-14 in quartz from existing samples collected at several sites in Antarctica to resolve major ambiguities in existing Last Glacial Maximum to present ice sheet reconstructions. This project is important because of the critical nature of accurate reconstructions of ice sheet change in constraining reconstructions of past sea level change. Although carbon-14 is most commonly exploited as a geochronometer through its production in the upper atmosphere and incorporation into organic materials, it is also produced within the crystal lattice of rocks and minerals that are exposed to the cosmic-ray flux at the Earth\u0027s surface. In this latter case, its concentration is proportional to the duration of surface exposure, and measurements of in-situ-produced carbon-14 can be used to date geological events that form or expose rock surfaces, for example, ice sheet expansion and retreat. Although carbon-14 is one of several trace radionuclides that can be used for this purpose, it is unique among them in that its half-life is short relative to the time scale of glacial-interglacial variations. Thus, in cases where rock surfaces in polar regions have been repeatedly covered and uncovered by ice sheet change during many glacial-interglacial cycles, carbon-14 measurements are uniquely suited to accurately dating the most recent episode of ice sheet advance and retreat. We aim to use this property to improve our understanding of Antarctic Ice Sheet change at a number of critically located sites at which other surface exposure dating methods have yielded ambiguous results. Geographically, these are focused in the Weddell Sea embayment of Antarctica, which is an area where the geometry of the Antarctic continent potentially permits large glacial-interglacial changes in ice volume but where existing geologic records of ice sheet change are particularly ambiguous. In addition, in-situ carbon-14 measurements, applied where independently constrained deglaciation chronologies already exist, can potentially allow us to date the last period of ice sheet advance as well as the most recent retreat.", "east": 171.42, "geometry": "POINT(12.86 -74.268)", "instruments": null, "is_usap_dc": true, "keywords": "Amd/Us; Cosmogenic Dating; GLACIER THICKNESS/ICE SHEET THICKNESS; AMD; USAP-DC; GLACIER ELEVATION/ICE SHEET ELEVATION; GLACIERS/ICE SHEETS; Carbon-14; USA/NSF; Weddell Sea Embayment; LABORATORY; FIELD SURVEYS; GLACIATION", "locations": "Weddell Sea Embayment", "north": -64.195, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Goehring, Brent; Balco, Gregory", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "ICE-D", "repositories": "ICE-D", "science_programs": null, "south": -84.341, "title": "COLLABORATIVE RESEARCH: Resolving Ambiguous Exposure-Age Chronologies of Antarctic Deglaciation with Measurements of In-Situ-Produced Cosmogenic Carbon-14", "uid": "p0010254", "west": -145.7}, {"awards": "2122248 Waters, Laura", "bounds_geometry": "POLYGON((-127.143608 -77.1380528,-127.1012394 -77.1380528,-127.0588708 -77.1380528,-127.0165022 -77.1380528,-126.9741336 -77.1380528,-126.931765 -77.1380528,-126.8893964 -77.1380528,-126.8470278 -77.1380528,-126.8046592 -77.1380528,-126.7622906 -77.1380528,-126.719922 -77.1380528,-126.719922 -77.14809141,-126.719922 -77.15813002,-126.719922 -77.16816863,-126.719922 -77.17820724,-126.719922 -77.18824585,-126.719922 -77.19828446,-126.719922 -77.20832307,-126.719922 -77.21836168,-126.719922 -77.22840029,-126.719922 -77.2384389,-126.7622906 -77.2384389,-126.8046592 -77.2384389,-126.8470278 -77.2384389,-126.8893964 -77.2384389,-126.931765 -77.2384389,-126.9741336 -77.2384389,-127.0165022 -77.2384389,-127.0588708 -77.2384389,-127.1012394 -77.2384389,-127.143608 -77.2384389,-127.143608 -77.22840029,-127.143608 -77.21836168,-127.143608 -77.20832307,-127.143608 -77.19828446,-127.143608 -77.18824585,-127.143608 -77.17820724,-127.143608 -77.16816863,-127.143608 -77.15813002,-127.143608 -77.14809141,-127.143608 -77.1380528))", "dataset_titles": null, "datasets": null, "date_created": "Thu, 19 Aug 2021 00:00:00 GMT", "description": "This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The geologic record reveals that volcanic activity increases when glaciers retreat and major ice sheets thin. This relationship produces a positive feedback mechanism where the uptick in volcanism increases greenhouse gasses concentrations, leading to climate warming and further deglaciation. Although the pattern between volcanism and deglaciation is observed in the geologic record, the exact mechanism(s) by which glaciers impact a volcanic plumbing system is unknown. This project focuses on Mount Waesche, a volcano in West Antarctica, that frequently erupts during warm, interglacial periods and undergoes a period of less activity during cold, glacial periods. This project will examine compositions of the rocks and minerals from Mount Waesche to determine magma storage depths, allowing the investigators to understand how magma plumbing systems change in response to glacial cycles. These results will be compared with geodynamic simulations to understand the physics behind the effects of deglaciation on the magmatic plumbing systems within Earth\u2019s crust. The investigators will additionally partner with Mentoring Kids Works to develop several Polar and Earth Science Educational Modules aimed at improving reading skills in third grade students in New Mexico. The proposed Polar and Earth Science program consists of modules that include readings of books introducing students to Earth and Polar science themes, paired with Earth and Polar Science activities, followed by simple experiments, where students make predictions and collect data. Information required to implement our Polar and Earth Science curriculum will be made available online. Isotopic and sedimentary datasets reveal that volcanic activity typically increases during interglacial periods. However, the physical mechanisms through which changes in the surface loading affect volcanic magmatic plumbing systems remain unconstrained. Recently generated 40Ar/39Ar eruption ages indicate that 86% of the dated samples from Mt. Waesche, a late Quaternary volcano in Marie Byrd land, correlate with interglacial periods, suggesting this volcano uniquely responds to changes in the West Antarctic Ice Sheet. We propose to combine the petrology of Mount Waesche\u2019s volcanic record, constraints on changing ice loads through time, and geodynamic modelling to: (1) Determine how pre-eruptive storage conditions change during glacial and interglacial periods using whole rock and mineral compositions of volcanic rocks; (2) Conduct geodynamic modeling to elucidate the relationship between lithospheric structure, temporal variations in ice sheet thickness, and subsequent changes in crustal stresses and magmatic transport and, therefore, the mechanism(s) by which deglaciation impacts magmatic plumbing systems; (3) Use the outcomes of objectives (1) and (2) to provide new constraints on the changes in ice sheet thickness through time that could plausibly trigger future volcanic and magmatic activity in West Antarctica. This collaborative approach will provide a novel methodology to determine prior magnitudes and rates of ice load changes within the Marie Byrd Land region of Antarctica. Lastly, estimates of WAIS elevation changes from this study will be compared to ongoing studies at Mount Waesche focused on constraining last interglacial ice sheet draw down using cosmogenic exposure ages obtained from shallow drilling. The scope of work also includes a partnership with Mentoring Kids Works to develop several Polar and Earth Science Educational Modules aimed at improving reading skills in third grade students in New Mexico. The proposed Polar and Earth Science program consists of modules that include readings of books introducing students to Earth and Polar science themes, paired with Earth and Polar Science activities, followed by simple experiments, where students make predictions and collect data. Information required to implement our Polar and Earth Science curriculum will be made available online. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -126.719922, "geometry": "POINT(-126.931765 -77.18824585)", "instruments": null, "is_usap_dc": true, "keywords": "Mt. Waesche; GEOCHEMISTRY; LITHOSPHERIC PLATE MOTION; STRESS; Amd/Us; West Antarctica; Executive Committee Range; NOT APPLICABLE; USAP-DC; AMD; MAJOR ELEMENTS; USA/NSF; ROCKS/MINERALS/CRYSTALS", "locations": "West Antarctica; Mt. Waesche; Executive Committee Range", "north": -77.1380528, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Waters, Laura; Naliboff, John; Zimmerer, Matthew", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repositories": null, "science_programs": null, "south": -77.2384389, "title": "Integrating petrologic records and geodynamics: Quantifying the effects of glaciation on crustal stress and eruptive patterns at Mt. Waesche, Executive Committee Range, Antarctica", "uid": "p0010248", "west": -127.143608}, {"awards": "1643494 Saal, Alberto", "bounds_geometry": "POLYGON((-68.074 -57.345,-66.6033 -57.345,-65.1326 -57.345,-63.6619 -57.345,-62.1912 -57.345,-60.7205 -57.345,-59.2498 -57.345,-57.7791 -57.345,-56.3084 -57.345,-54.8377 -57.345,-53.367 -57.345,-53.367 -58.12517,-53.367 -58.90534,-53.367 -59.68551,-53.367 -60.46568,-53.367 -61.24585,-53.367 -62.02602,-53.367 -62.80619,-53.367 -63.58636,-53.367 -64.36653,-53.367 -65.1467,-54.8377 -65.1467,-56.3084 -65.1467,-57.7791 -65.1467,-59.2498 -65.1467,-60.7205 -65.1467,-62.1912 -65.1467,-63.6619 -65.1467,-65.1326 -65.1467,-66.6033 -65.1467,-68.074 -65.1467,-68.074 -64.36653,-68.074 -63.58636,-68.074 -62.80619,-68.074 -62.02602,-68.074 -61.24585,-68.074 -60.46568,-68.074 -59.68551,-68.074 -58.90534,-68.074 -58.12517,-68.074 -57.345))", "dataset_titles": "Major, trace elements contents and radiogenic isotopes of erupted lavas Antarctic Peninsula and Phoenix Ridge", "datasets": [{"dataset_uid": "601519", "doi": "10.15784/601519", "keywords": "Antarctica; Antarctic Peninsula; Chemical Composition; Chemistry:rock; Chemistry:Rock; Geochemistry; Isotope Data; Trace Elements", "people": "Saal, Alberto", "repository": "USAP-DC", "science_program": null, "title": "Major, trace elements contents and radiogenic isotopes of erupted lavas Antarctic Peninsula and Phoenix Ridge", "url": "https://www.usap-dc.org/view/dataset/601519"}], "date_created": "Tue, 22 Jun 2021 00:00:00 GMT", "description": "The Earth\u0027s mantle influences the movement of tectonic plates and volcanism on the surface. One way to understand the composition and nature of the Earth\u0027s mantle is by studying the chemistry of basalts, which originate by volcanic eruptions of partially melting mantle rocks. This study will establish the budget and distribution of volatile elements (hydrogen, carbon, fluorine, chlorine, sulfur) in volcanic basalts to better understand the composition of the Earth\u0027s interior. Volatiles influence mantle melting, magma crystallization, magma migration and volcanic eruptions. Their abundances and spatial distribution provide important constraints on models of mantle flow and temperature. Moreover, volatiles are key constituents of the Earth\u0027s atmosphere and oceans. Establishing the cycles of volatiles between the Earth\u0027s interior and surface is of fundamental importance to understand the long-term evolution of our planet. This project supports a graduate student and research scientist at Brown University. It promotes the collaboration with geochemists from eleven institutions representing six different countries: USA, Germany, United Kingdom, Argentina, South Korea and Japan, and utilizes several NSF-funded USA analytical facilities. Communication of results will occur through: 1) peer-reviewed journals, presentations at conferences and invited university lectures, 2) hands-on science learning activities for local elementary and high school classes, and 3) outreach to the general audience through public lectures. Over the last 60 years of funded research, the Antarctic Peninsula and nearby ocean ridges have been extensively investigated providing information on the origin of the magmatism, and the composition, structure, temperature and evolution of the lithospheric and asthenospheric mantle. Diverse hypotheses have been proposed for the origin of the magmatism in the Antarctic Peninsula, from flux melting of the mantle wedge during devolatilization of the subducted Phoenix plate, to adiabatic decompression melting of a carbonated and hydrous asthenosphere, to melting of a volatile-rich metasomatized subcontinental lithospheric mantle. All proposed hypotheses invoke the role of volatiles. Surprisingly, data on the volatile contents of basalts and mantle from this region are non-existent. This is a significant omission from the geochemical data set, given the important role volatile elements play in the generation and composition of magmas and their sources. The focus of our research is to examine the regional variations in volatile contents (C, H, F, S, Cl) in geochemically well-characterized Pliocene-recent basalts from the Antarctic Peninsula and Phoenix ridge. Our goal is to establish the budget and distribution of volatiles in the mantle to understand 1) the processes responsible for the generation of chemically diverse basalts in close spatial and temporal proximity and 2) the nature (lithology, composition and temperature) of the heterogeneous mantle source beneath the Antarctic Peninsula and Phoenix ridge.", "east": -53.367, "geometry": "POINT(-60.7205 -61.24585)", "instruments": null, "is_usap_dc": true, "keywords": "Antarctic Peninsula; USA/NSF; USAP-DC; TRACE ELEMENTS; MAJOR ELEMENTS; Amd/Us; LABORATORY; ROCKS/MINERALS/CRYSTALS; Magmatic Volatiles; AMD", "locations": "Antarctic Peninsula", "north": -57.345, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Saal, Alberto", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -65.1467, "title": "Magmatic Volatiles, Unraveling the Reservoirs and Processes of the Volcanism in the Antarctic Peninsula", "uid": "p0010196", "west": -68.074}, {"awards": "2045611 Rasbury, Emma; 2042495 Blackburn, Terrence", "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))", "dataset_titles": " Subglacial Precipitates Record Antarctic Ice Sheet Response to Pleistocene Millennial Climate Cycles; Subglacial precipitates record Antarctic ice sheet response to Southern Ocean warming ; Thermogenic Methane Production in Antarctic Subglacial Hydrocarbon Seeps; U-Th isotopes and major elements in sediments from Taylor Valley, Antarctica", "datasets": [{"dataset_uid": "601918", "doi": "10.15784/601918", "keywords": "Antarctica; Carbon Isotopes; Cryosphere; East Antarctica; Elephant Moraine; Geochronology; Isotope Data; Subglacial", "people": "Piccione, Gavin", "repository": "USAP-DC", "science_program": null, "title": "Thermogenic Methane Production in Antarctic Subglacial Hydrocarbon Seeps", "url": "https://www.usap-dc.org/view/dataset/601918"}, {"dataset_uid": "601911", "doi": null, "keywords": "Antarctica; Cryosphere", "people": "Gagliardi, Jessica", "repository": "USAP-DC", "science_program": null, "title": "Subglacial precipitates record Antarctic ice sheet response to Southern Ocean warming ", "url": "https://www.usap-dc.org/view/dataset/601911"}, {"dataset_uid": "601594", "doi": "10.15784/601594", "keywords": "Antarctica; East Antarctica", "people": "Blackburn, Terrence; Piccione, Gavin", "repository": "USAP-DC", "science_program": null, "title": " Subglacial Precipitates Record Antarctic Ice Sheet Response to Pleistocene Millennial Climate Cycles", "url": "https://www.usap-dc.org/view/dataset/601594"}, {"dataset_uid": "601806", "doi": "10.15784/601806", "keywords": "Antarctica; Cryosphere; Erosion; Isotope Data; Major Elements; Soil; Taylor Glacier; Taylor Valley", "people": "Piccione, Gavin; Edwards, Graham; Tulaczyk, Slawek; Blackburn, Terrence", "repository": "USAP-DC", "science_program": null, "title": "U-Th isotopes and major elements in sediments from Taylor Valley, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601806"}], "date_created": "Fri, 18 Jun 2021 00:00:00 GMT", "description": "Over the past century, climate science has constructed an extensive record of Earth\u2019s ice age cycles through the chemical and isotopic characterization of various geologic archives such as polar ice cores, deep-ocean sediments, and cave speleothems. These climatic archives provide an insightful picture of ice age cycles and of the related large global sea level fluctuations triggered by these significant climate rhythms. However, such records still provide limited insight as to how or which of Earth\u2019s ice sheets contributed to higher sea levels during past warm climate periods. This is of particular importance for our modern world: the Antarctic ice sheet is currently the world\u2019s largest freshwater reservoir, which, if completely melted, would raise the global sea level by over 60 meters (200 feet). Yet, geologic records of Antarctic ice sheet sensitivity to warm climates are particularly limited and difficult to obtain, because the direct records of ice sheet geometry smaller than the modern one are still buried beneath the mile-thick ice covering the continent. Therefore, it remains unclear how much this ice sheet contributed to past sea level rise during warm climate periods or how it will respond to the anticipated near-future climate warming. In the proposed research we seek to develop sub-ice chemical precipitates\u2014minerals that form in lakes found beneath the ice sheet\u2014as a climatic archive, one that records how the Antarctic ice sheet responded to past climatic change. These sub-ice mineral formations accumulated beneath the ice for over a hundred thousand years, recording the changes in chemical and isotopic subglacial properties that occur in response to climate change. Eventually these samples were eroded by the ice sheet and moved to the Antarctic ice margin where they were collected and made available to study. This research will utilize advanced geochemical, isotopic and geochronologic techniques to develop record of the Antarctica ice sheet\u2019s past response to warm climate periods, directly informing efforts to understand how Antarctica will response to future warming. Efforts to improve sea level forecasting on a warming planet have focused on determining the temperature, sea level and extent of polar ice sheets during Earth\u2019s past warm periods. Large uncertainties, however, in reconstructions of past and future sea levels, result from the poorly constrained climate sensitivity of the Antarctic Ice sheet (AIS). This research project aims to develop the use of subglacial precipitates as an archive the Antarctic ice sheet (AIS) past response to climate change. The subglacial precipitates from East Antarctica form in water bodies beneath Antarctic ice and in doing so provide an entirely new and unique measure of how the AIS responds to climate change. In preliminary examination of these precipitates, we identified multiple samples consisting of cyclic opal and calcite that spans hundreds of thousands of years in duration. Our preliminary geochemical characterization of these samples indicates that the observed mineralogic changes result from a cyclic change in subglacial water compositions between isotopically and chemically distinct waters. Opal-forming waters are reduced (Ce* \u003c1 and high Fe/Mn) and exhibit elevated 234U/238U compositions similar to the saline groundwater brines found at the periphery of the AIS. Calcite-forming waters, are rather, oxidized and exhibit \u03b418O compositions consistent with derivation from the depleted polar plateau (\u003c -50 \u2030). 234U-230Th dates permit construction of a robust timeseries describing these mineralogic and compositional changes through time. Comparisons of these time series with other Antarctic climate records (e.g., ice core records) reveal that calcite forming events align with millennial scale changes in local temperature or \u201cAntarctic isotopic maximums\u201d, which represent Southern Hemisphere warm periods resulting in increased Atlantic Meridional overturing circulation. Ultimately, this project seeks to develop a comprehensive model as to how changes in the thermohaline cycle induce a glaciologic response which in turn induces a change in the composition of subglacial waters and the mineralogic phase recorded within the precipitate archive. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": 180.0, "geometry": "POINT(0 -89.999)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; FIELD INVESTIGATION; AMD; USA/NSF; Amd/Us; USAP-DC; East Antarctica", "locations": "East Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Blackburn, Terrence; Tulaczyk, Slawek; Hain, Mathis; Rasbury, Troy", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Reconstructing East Antarctica\u2019s Past Response to Climate using Subglacial Precipitates", "uid": "p0010192", "west": -180.0}, {"awards": "1443342 Licht, Kathy; 1443556 Thomson, Stuart", "bounds_geometry": null, "dataset_titles": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "datasets": [{"dataset_uid": "601462", "doi": "10.15784/601462", "keywords": "Antarctica; Beardmore Glacier; Erosion; Landscape Evolution; Shackleton Glacier; Transantarctic Mountains; (U-Th)/He", "people": "Thomson, Stuart; Licht, Kathy; Hemming, Sidney R.; Reiners, Peter; He, John", "repository": "USAP-DC", "science_program": null, "title": "Apatite (U-Th)/He and TREE Data Central Transantarctic Mountains", "url": "https://www.usap-dc.org/view/dataset/601462"}], "date_created": "Wed, 09 Jun 2021 00:00:00 GMT", "description": "Antarctica is almost entirely covered by ice, in places over two miles thick. This ice hides a landscape that is less well known than the surface of Mars and represents one of Earth\u0027s last unexplored frontiers. Ice-penetrating radar images provide a remote glimpse of this landscape including ice-buried mountains larger than the European Alps and huge fjords twice as deep as the Grand Canyon. The goal of this project is to collect sediment samples derived from these landscapes to determine when and under what conditions these features formed. Specifically, the project seeks to understand the landscape in the context of the history and dynamics of the overlying ice sheet and past mountain-building episodes. This project accomplishes this goal by analyzing sand collected during previous sea-floor drilling expeditions off the coast of Antarctica. This sand was supplied from the continent interior by ancient rivers when it was ice-free over 34 million year ago, and later by glaciers. The project will also study bedrock samples from rare ice-free parts of the Transantarctic Mountains. The primary activity is to apply multiple advanced dating techniques to single mineral grains contained within this sand and rock. Different methods and minerals yield different dates that provide insight into how Antarctica?s landscape has eroded over the many tens of millions of years during which sand was deposited offshore. The dating techniques that are being developed and enhanced for this study have broad application in many branches of geoscience research and industry. The project makes cost-effective use of pre-existing sample collections housed at NSF facilities including the US Polar Rock Repository, the Gulf Coast Core Repository, and the Antarctic Marine Geology Research Facility. The project will contribute to the STEM training of two graduate and two undergraduate students, and includes collaboration among four US universities as well as international collaboration between the US and France. The project also supports outreach in the form of a two-week open workshop giving ten students the opportunity to visit the University of Arizona to conduct STEM-based analytical work and training on Antarctic-based projects. Results from both the project and workshop will be disseminated through presentations at professional meetings, peer-reviewed publications, and through public outreach and media. The main objective of this project is to reconstruct a chronology of East Antarctic subglacial landscape evolution to understand the tectonic and climatic forcing behind landscape modification, and how it has influenced past ice sheet inception and dynamics. Our approach focuses on acquiring a record of the cooling and erosion history contained in East Antarctic-derived detrital mineral grains and clasts in offshore sediments deposited both before and after the onset of Antarctic glaciation. Samples will be taken from existing drill core and marine sediment core material from offshore Wilkes Land (100\u00b0E-160\u00b0E) and the Ross Sea. Multiple geo- and thermo-chronometers will be employed to reconstruct source region cooling history including U-Pb, fission-track, and (U-Th)/He dating of zircon and apatite, and 40Ar/39Ar dating of hornblende, mica, and feldspar. This offshore record will be augmented and tested by applying the same methods to onshore bedrock samples in the Transantarctic Mountains obtained from the US Polar Rock Repository and through fieldwork. The onshore work will additionally address the debated incision history of the large glacial troughs that cut the range, now occupied by glaciers draining the East Antarctic Ice Sheet. This includes collection of samples from several age-elevation transects, apatite 4He/3He thermochronometry, and Pecube thermo-kinematic modeling. Acquiring an extensive geo- and thermo-chronologic database will also provide valuable new information on the poorly known ice-hidden geology and tectonics of subglacial East Antarctica that has implications for improving supercontinent reconstructions and understanding continental break-up.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "LABORATORY; LANDSCAPE; AGE DETERMINATIONS; FIELD INVESTIGATION; GLACIAL PROCESSES; Transantarctic Mountains; USA/NSF; Thermochronology; Amd/Us; USAP-DC; TRACE ELEMENTS; Provenance Analysis; AMD; LANDFORMS; GLACIAL LANDFORMS", "locations": "Transantarctic Mountains", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Thomson, Stuart; Reiners, Peter; Licht, Kathy", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Collaborative Research: East Antarctic Glacial Landscape Evolution (EAGLE): A Study using Combined Thermochronology, Geochronology and Provenance Analysis", "uid": "p0010188", "west": null}, {"awards": "1543344 Soreghan, Gerilyn", "bounds_geometry": null, "dataset_titles": "Data and metadata for \"Quantifying surface area in muds from the Antarctic Dry Valleys: Implications for weathering in glacial systems\"", "datasets": [{"dataset_uid": "601599", "doi": "10.15784/601599", "keywords": "Antarctica; Anza Borrego; Iceland; McMurdo Dry Valleys; Norway; Peru; Puerto Rico; Taylor Valley; Washington; Wright Valley", "people": "Demirel-Floyd, Cansu", "repository": "USAP-DC", "science_program": null, "title": "Data and metadata for \"Quantifying surface area in muds from the Antarctic Dry Valleys: Implications for weathering in glacial systems\"", "url": "https://www.usap-dc.org/view/dataset/601599"}], "date_created": "Tue, 18 May 2021 00:00:00 GMT", "description": "As glaciers creep across the landscape, they can act as earthmovers, plucking up rocks and grinding them into fine sediments. Glaciers have moved across the Antarctic landscape over thousands to millions of years, leaving these ground-up sediments in their wake. This study builds on pilot discoveries by the investigators that revealed remarkably large and variable measurements of surface area in glacially-derived fine-grained sediments found in the McMurdo Dry Valleys (MDV), one of the few landscapes on the Antarctic continent not currently covered by ice. Surface area is key to chemical weathering, the process by which rock is converted to soils as ions are carried away in streams and groundwater. These chemical weathering processes are also one of the primary means by which the Earth system naturally removes carbon dioxide from the atmosphere. Hence, high surface areas observed in sediments implies high \"weatherability\" which in turn translates to more potential carbon dioxide removed from the atmosphere. Therefore, chemical weathering in high surface area glacial sediments may have significant impacts on Earth\u0027s carbon cycle. The researchers will measure the chemical and physical properties of sediments previously collected from the Dry Valleys to understand what factors lead to production of sediment with high-surface area and potential \"weather ability\" and investigate how sediment produced in these glacial systems could ultimately impact Earth\u0027s carbon budget. Results from this research will help scientists (including modelers) refine predictions of the effects of melting glaciers- and attendant exposure of glacial sediment? on atmospheric carbon levels. These results may also contribute to applied research efforts on development of carbon-dioxide removal technologies utilizing principles of rock weathering. In addition to the scientific benefits, this research will involve several students at the undergraduate, graduate, and post-doctoral levels, including science education undergraduates, thus contributing to training of the next-generation STEM workforce. Physical weathering produces fresh surfaces, greatly enhancing specific surface area (SSA) and reactive surface area (RSA) of primary minerals. Quantifying SSA and RSA of sediments is key to determining dissolution and leaching rates during natural weathering, but few data exist on distribution of sediment SA, particularly in glacial and fluvial systems. Pilot data from glacial stream systems in Taylor Valley and Wright Valley (located in the MDV) exhibit remarkably high and variable values in both SSA and RSA, values that in some cases greatly exceed values from muds in temperate glacial systems. This discovery motivates the current research, which aims to investigate the hypothesis that high and variable SAs of muds within Wright and Taylor Valleys reflect textural and/or compositional inheritance from the differing depositional settings within the MDV, biologic controls, dust additions, and/or pedogenic processes. These hypotheses will be tested by sedimentologically, mineralogically, and geochemically characterizing muds from glacially derived sediment deposited in various environments (cold vs. wet based glaciation; fluvial, lacustrine, dust, and drift deposits) and of varying age (Miocene to Modern) from the MDV and quantifying variation of SA and reactivity. Comparisons with analyzed muds from temperate glacial systems will enable polar-temperate comparisons. Analyses will focus on muds of previously collected sediment from the MDVs. Grain size and SSA will be measured by Laser Analysis and N2 adsorption BET, respectively. After carbonate removal, samples will be re-analyzed for SSA, and muds characterized geochemically. Mineralogy and bulk chemistry will also be assessed on co-occurring sand fractions, and textural attributes documented. SSA-normalized dissolution experiments will be used to compare solutes released from sediments to determine RSAs. Results will be integrated with the various sedimentologic and geochemical analyses to test the posed hypotheses. Ultimately, this research should shed light on how weathering in Antarctic systems contributes to global carbon cycling.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "USAP-DC; AMD; FIELD INVESTIGATION; USA/NSF; Dry Valleys; SEDIMENT CHEMISTRY; Amd/Us; Antarctica; Weathering", "locations": "Antarctica; Dry Valleys", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Soreghan, Gerilyn; Elwood Madden, Megan", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "Quantifying surface area in muds from the Antarctic Dry Valleys: Implications for weathering in glacial systems", "uid": "p0010181", "west": null}, {"awards": "2048351 Lindow, Julia", "bounds_geometry": null, "dataset_titles": "Cosmogenic nuclide data for Bennett Platform, Antarctica", "datasets": [{"dataset_uid": "601954", "doi": null, "keywords": "Antarctica; Beryllium; Cryosphere; Helium; Neon", "people": "Kurz, Mark D.; Lindow, Julia", "repository": "USAP-DC", "science_program": null, "title": "Cosmogenic nuclide data for Bennett Platform, Antarctica", "url": "https://www.usap-dc.org/view/dataset/601954"}], "date_created": "Fri, 26 Feb 2021 00:00:00 GMT", "description": "Part I: Nontechnical Antarcticas ice sheets constitute the largest ice mass on Earth, with approximately 53 meters of sea level equivalent stored in the East Antarctic Ice Sheet alone. The history of the East Antarctic Ice Sheet is therefore important to understanding and predicting changes in sea level and Earths climate. There is conflicting evidence regarding long-term stability of the East Antarctic Ice Sheet, over the last twenty million years. To better understand past ice sheet changes, together with the history of the Transantarctic Mountains, accurate time scales are needed. One of the few dating methods applicable to the Antarctic glacial deposits, that record past ice sheet changes, is the measurement of rare isotopes produced by cosmic rays in surface rock samples, referred to as cosmogenic nuclides. Whenever a rock surface is exposed/free of cover, cosmic rays produce rare isotopes such as helium-3, beryllium-10, and neon-21within the minerals. This project will involve measurement of all three isotopes in some of the oldest glacial deposits found at high elevation in the Transantarctic Mountains. Because the amount of each isotope is directly linked to the exposure time, this can be used to calculate the age of a surface. This method requires knowledge of the rates that cosmic radiation produces each isotope, which depends upon mineral composition, and is presently a limitation of the method. The goal of this project is to advance and enhance existing measurement methods and expand the range of possibilities in surface dating with new measurements of all three isotopes in pyroxene, a mineral that is commonly found throughout the Transantarctic Mountains. This technological progress will allow a better application of the surface exposure dating method, which in turn will help to reconstruct Antarctic ice sheet history and provide valuable knowledge of former ice-extent. Understanding Antarcticas ice-sheet history is crucial to predict its influence on past and future sea level changes. \r\n Part II: Technical Description Measurements of in-situ produced cosmogenic nuclides in Antarctic surficial rock samples provide unique time scales for glacial and landscape evolution processes. However, due to analytical challenges, pyroxene-bearing and widely distributed lithologies like the Ferrar dolerite of the Transantarctic Mountains, are underutilized. This proposal aims to changes this and to improve the cosmogenic nuclide methodologies for stable isotopes (21Ne and 3He) and radioactive nuclides (10Be) in pyroxenes. Proposed methodological improvements will be directly applicable to erosion rates and deposition ages of important glacial deposits, such as the controversial Sirius Group tills, and also to younger glacial features. Bennett Platform is the focus of this study because it is one of the southern-most Sirius Group outcrops along the Transantarctic Mountains, where cosmogenic ages are sparse. \r\n Preliminary measurements demonstrate large discrepancies between 3He and 21Ne age determinations in Sirius Group pyroxenes. One possible explanation is composition dependence of the 21Ne production rates. Coupled measurements of 3He, 21Ne, and 10Be in well-characterized pyroxene mineral separates from Ferrar dolerite will be used to better constrain the production rates, major element and trace element dependencies, the assumptions of the method, and ultimately advance the application of cosmogenic nuclides to mafic Antarctic lithologies. \r\n The main goals of this study are to improve measurement protocols for 10Be in pyroxene, and the determination of the composition dependence of 21Ne production rates by measuring mineral compositions (by electron microprobe), and nuclide concentrations in mineral pairs from young lava flows. Further aims are the validation of the nucleogenic contributions and the effects of helium diffusive loss through measurements of 3He/21Ne production ratios, combined with measurements of shielded samples of the Ferrar dolerite. Combined measurements of 3He, 21Ne and 10Be in pyroxenes have rarely been published for individual samples in Antarctica. The new and unique measurements of this study will advance the applicability of in-situ produced cosmogenic nuclides to both young and ancient Antarctic surfaces. The study will be performed using existing samples: no field work is requested. \r\n This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "FIELD INVESTIGATION; LABORATORY; LANDSCAPE; Transantarctic Mountains; GLACIAL LANDFORMS", "locations": "Transantarctic Mountains", "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Lindow, Julia; Kurz, Mark D.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": null, "title": "New Cosmogenic 21Ne and 10Be Measurements in the Transantarctic Mountains", "uid": "p0010163", "west": null}, {"awards": "1724670 Williams, Trevor", "bounds_geometry": "POLYGON((-70 -60,-65 -60,-60 -60,-55 -60,-50 -60,-45 -60,-40 -60,-35 -60,-30 -60,-25 -60,-20 -60,-20 -62.5,-20 -65,-20 -67.5,-20 -70,-20 -72.5,-20 -75,-20 -77.5,-20 -80,-20 -82.5,-20 -85,-25 -85,-30 -85,-35 -85,-40 -85,-45 -85,-50 -85,-55 -85,-60 -85,-65 -85,-70 -85,-70 -82.5,-70 -80,-70 -77.5,-70 -75,-70 -72.5,-70 -70,-70 -67.5,-70 -65,-70 -62.5,-70 -60))", "dataset_titles": "Argon thermochronological data on detrital mineral grains from the Weddell Sea embayment", "datasets": [{"dataset_uid": "601377", "doi": "10.15784/601377", "keywords": "40Ar/39Ar Thermochronology; Antarctica; Argon; Chemistry:sediment; Chemistry:Sediment; Detrital Minerals; Glaciers/ice Sheet; Glaciers/Ice Sheet; Marine Sediments; Mass Spectrometer; Provenance; R/v Polarstern; Sediment Core Data; Subglacial Till; Till; Weddell Sea", "people": "Williams, Trevor", "repository": "USAP-DC", "science_program": null, "title": "Argon thermochronological data on detrital mineral grains from the Weddell Sea embayment", "url": "https://www.usap-dc.org/view/dataset/601377"}, {"dataset_uid": "601378", "doi": "10.15784/601378", "keywords": "40Ar/39Ar Thermochronology; Antarctica; Argon; Chemistry:sediment; Chemistry:Sediment; Detrital Minerals; Glaciers/ice Sheet; Glaciers/Ice Sheet; Marine Sediments; Mass Spectrometer; Provenance; R/v Polarstern; Sediment Core Data; Subglacial Till; Till; Weddell Sea", "people": "Williams, Trevor", "repository": "USAP-DC", "science_program": null, "title": "Argon thermochronological data on detrital mineral grains from the Weddell Sea embayment", "url": "https://www.usap-dc.org/view/dataset/601378"}, {"dataset_uid": "601379", "doi": "10.15784/601379", "keywords": "40Ar/39Ar Thermochronology; Antarctica; Argon; Chemistry:sediment; Chemistry:Sediment; Detrital Minerals; Glaciers/ice Sheet; Glaciers/Ice Sheet; Marine Geoscience; Mass Spectrometer; Provenance; R/v Polarstern; Sediment Core Data; Subglacial Till; Till; Weddell Sea", "people": "Williams, Trevor", "repository": "USAP-DC", "science_program": null, "title": "Argon thermochronological data on detrital mineral grains from the Weddell Sea embayment", "url": "https://www.usap-dc.org/view/dataset/601379"}], "date_created": "Thu, 10 Sep 2020 00:00:00 GMT", "description": "Abstract for the general public: The margins of the Antarctic ice sheet have advanced and retreated repeatedly over the past few million years. Melting ice from the last retreat, from 19,000 to 9,000 years ago, raised sea levels by 8 meters or more, but the extents of previous retreats are less well known. The main goal of this project is to understand how Antarctic ice retreats: fast or slow, stepped or steady, and which parts of the ice sheet are most prone to retreat. Antarctica loses ice by two main processes: melting of the underside of floating ice shelves and calving of icebergs. Icebergs themselves are ephemeral, but they carry mineral grains and rock fragments that have been scoured from Antarctic bedrock. As the icebergs drift and melt, this \u0027iceberg-rafted debris\u0027 falls to the sea-bed and is steadily buried in marine sediments to form a record of iceberg activity and ice sheet retreat. The investigators will read this record of iceberg-rafted debris to find when and where Antarctic ice destabilized in the past. This information can help to predict how Antarctic ice will behave in a warming climate. The study area is the Weddell Sea embayment, in the Atlantic sector of Antarctica. Principal sources of icebergs are the nearby Antarctic Peninsula and Weddell Sea embayment, where ice streams drain about a quarter of Antarctic ice. The provenance of the iceberg-rafted debris (IRD), and the icebergs that carried it, will be found by matching the geochemical fingerprint (such as characteristic argon isotope ages) of individual mineral grains in the IRD to that of the corresponding source area. In more detail, the project will: 1. Define the geochemical fingerprints of the source areas of the glacially-eroded material using samples from each major ice stream entering the Weddell Sea. Existing data indicates that the hinterland of the Weddell embayment is made up of geochemically distinguishable source areas, making it possible to apply geochemical provenance techniques to determine the origin of Antarctica icebergs. Few samples of onshore tills are available from this area, so this project includes fieldwork to collect till samples to characterize detritus supplied by the Recovery and Foundation ice streams. 2. Document the stratigraphic changes in provenance of iceberg-rafted debris (IRD) and glacially-eroded material in two deep water sediment cores in the NW Weddell Sea. Icebergs calved from ice streams in the embayment are carried by the Weddell Gyre and deposit IRD as they pass over the core sites. The provenance information identifies which groups of ice streams were actively eroding and exporting detritus to the ocean (via iceberg rafting and bottom currents), and the stratigraphy of the cores shows the relative sequence of ice stream activity through time. A further dimension is added by determining the time lag between fine sediment erosion and deposition, using a new method of uranium-series isotope measurements in fine grained material. Technical abstract: The behavior of the Antarctic ice sheets and ice streams is a critical topic for climate change and future sea level rise. The goal of this proposal is to constrain ice sheet response to changing climate in the Weddell Sea during the three most recent glacial terminations, as analogues for potential future warming. The project will also examine possible contributions to Meltwater Pulse 1A, and test the relative stability of the ice streams draining East and West Antarctica. Much of the West Antarctic ice may have melted during the Eemian (130 to 114 Ka), so it may be an analogue for predicting future ice drawdown over the coming centuries. Geochemical provenance fingerprinting of glacially eroded detritus provides a novel way to reconstruct the location and relative timing of glacial retreat during these terminations in the Weddell Sea embayment. The two major objectives of the project are to: 1. Define the provenance source areas by characterizing Ar, U-Pb, and Nd isotopic signatures, and heavy mineral and Fe-Ti oxide compositions of detrital minerals from each major ice stream entering the Weddell Sea, using onshore tills and existing sediment cores from the Ronne and Filchner Ice Shelves. Pilot data demonstrate that detritus originating from the east and west sides of the Weddell Sea embayment can be clearly distinguished, and published data indicates that the hinterland of the embayment is made up of geochemically distinguishable source areas. Few samples of onshore tills are available from this area, so this project includes fieldwork to collect till to characterize detritus supplied by the Recovery and Foundation ice streams. 2. Document the stratigraphic changes in provenance of iceberg-rafted debris (IRD) and glacially-eroded material in two deep water sediment cores in the NW Weddell Sea. Icebergs calved from ice streams in the embayment are carried by the Weddell Gyre and deposit IRD as they pass over the core sites. The provenance information will identify which ice streams were actively eroding and exporting detritus to the ocean (via iceberg rafting and bottom currents). The stratigraphy of the cores will show the relative sequence of ice stream activity through time. A further time dimension is added by determining the time lag between fine sediment erosion and deposition, using U-series comminution ages.", "east": -20.0, "geometry": "POINT(-45 -72.5)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SEDIMENT CORERS; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e MASS SPECTROMETERS", "is_usap_dc": true, "keywords": "TERRIGENOUS SEDIMENTS; Subglacial Till; USAP-DC; ICEBERGS; AMD; USA/NSF; ISOTOPES; AGE DETERMINATIONS; Argon; Provenance; Till; Amd/Us; R/V POLARSTERN; FIELD INVESTIGATION; SEDIMENT CHEMISTRY; Weddell Sea; Antarctica; LABORATORY", "locations": "Weddell Sea; Antarctica", "north": -60.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Williams, Trevor; Hemming, Sidney R.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY; WATER-BASED PLATFORMS \u003e VESSELS \u003e SURFACE \u003e R/V POLARSTERN", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -85.0, "title": "Collaborative Research: Deglacial Ice Dynamics in the Weddell Sea Embayment using Sediment Provenance", "uid": "p0010128", "west": -70.0}, {"awards": "1644027 Wallace, Paul; 1644020 Sims, Kenneth W.; 1644013 Gaetani, Glenn", "bounds_geometry": "POLYGON((164.1 -77.1,164.65 -77.1,165.2 -77.1,165.75 -77.1,166.3 -77.1,166.85 -77.1,167.4 -77.1,167.95 -77.1,168.5 -77.1,169.05 -77.1,169.6 -77.1,169.6 -77.235,169.6 -77.37,169.6 -77.505,169.6 -77.64,169.6 -77.775,169.6 -77.91,169.6 -78.045,169.6 -78.18,169.6 -78.315,169.6 -78.45,169.05 -78.45,168.5 -78.45,167.95 -78.45,167.4 -78.45,166.85 -78.45,166.3 -78.45,165.75 -78.45,165.2 -78.45,164.65 -78.45,164.1 -78.45,164.1 -78.315,164.1 -78.18,164.1 -78.045,164.1 -77.91,164.1 -77.775,164.1 -77.64,164.1 -77.505,164.1 -77.37,164.1 -77.235,164.1 -77.1))", "dataset_titles": "G170 Electron Microprobe Analyses of Melt Inclusions and Host Olivines; G170 Raman Spectroscopy \u0026 Tomography Volumes of Melt Inclusions and Vapor Bubbles; G170 Sample Locations Ross Island \u0026 Discovery Province; G170 Secondary Ion Mass Spectrometry Analses of Melt Inclusion Volatiles; G170 Secondary Ion Mass Spectrometry Analyses of Melt Inclusion Hydrogen Isotopes; Location and Description of Tephra Samples from the Erebus and Discovery Sub-provinces", "datasets": [{"dataset_uid": "601507", "doi": "10.15784/601507", "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Geochemistry; Hydrogen; Ion Mass Spectrometry; Ross Island", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Secondary Ion Mass Spectrometry Analyses of Melt Inclusion Hydrogen Isotopes", "url": "https://www.usap-dc.org/view/dataset/601507"}, {"dataset_uid": "601505", "doi": "10.15784/601505", "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Electron Microprobe Analyses; Olivine; Petrography; Ross Island", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Electron Microprobe Analyses of Melt Inclusions and Host Olivines", "url": "https://www.usap-dc.org/view/dataset/601505"}, {"dataset_uid": "601504", "doi": "10.15784/601504", "keywords": "Antarctica; Ross Island; Sample/collection Description; Sample/Collection Description; Sample Location", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Sample Locations Ross Island \u0026 Discovery Province", "url": "https://www.usap-dc.org/view/dataset/601504"}, {"dataset_uid": "601250", "doi": "10.15784/601250", "keywords": "Antarctica; Hut Point Peninsula; Mt. Bird; Mt. Morning; Mt. Terror; Ross Island; Turks Head; Turtle Rock", "people": "Pamukcu, Ayla; Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "Location and Description of Tephra Samples from the Erebus and Discovery Sub-provinces", "url": "https://www.usap-dc.org/view/dataset/601250"}, {"dataset_uid": "601508", "doi": "10.15784/601508", "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Geochemistry; Melt Inclusions; Raman Spectroscopy; Ross Island; Vapor Bubbles; Volcanic", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Raman Spectroscopy \u0026 Tomography Volumes of Melt Inclusions and Vapor Bubbles", "url": "https://www.usap-dc.org/view/dataset/601508"}, {"dataset_uid": "601506", "doi": "10.15784/601506", "keywords": "Antarctica; Ion Mass Spectrometry; Ross Island; Volatiles", "people": "Gaetani, Glenn", "repository": "USAP-DC", "science_program": null, "title": "G170 Secondary Ion Mass Spectrometry Analses of Melt Inclusion Volatiles", "url": "https://www.usap-dc.org/view/dataset/601506"}], "date_created": "Sat, 08 Feb 2020 00:00:00 GMT", "description": "Nontechnical project description Globally, 500 million people live near and are threatened by active volcanoes. An important step in mitigating volcanic hazards is understanding the variables that influence the explosivity of eruptions. The rate at which a magma ascends from the reservoir within the Earth to the surface is one such variable. However, magma ascent rates are particularly difficult to determine because of the lack of reliable methods for investigating the process. This research applies a new approach to study magma storage depths and ascent rates at the Erebus volcanic province of Antarctica, one of Earth\u0027s largest alkaline volcanic centers. Small pockets of magma that become trapped within growing olivine crystals are called melt inclusions. The concentrations of water and carbon dioxide in these melt inclusions preserve information on the depth of magma reservoirs. Changes to the concentration and isotopic composition of water in the inclusions provide information on how long it took for the host magma to rise to the surface. In combination, these data from samples of olivine-rich volcanic deposits in the Erebus volcanic province will be used to determine the depths at which magmas are stored and their ascent rates. The project results will provide a framework for understanding volcanic hazards associated with alkaline volcanism worldwide. In addition, this project facilitates collaboration among three institutions, and provides an important educational opportunity for a postdoctoral researcher. Technical project description The depths at which magmas are stored, their pre-eruptive volatile contents, and the rates at which they ascend to the Earth\u0027s surface are important controls on the dynamics of volcanic eruptions. Basaltic magmas are likely to be vapor undersaturated as they begin their ascent from the mantle through the crust, but volatile solubility drops with decreasing pressure. Once vapor saturation is achieved and the magma begins to degas, its pre-eruptive volatile content is determined largely by the depth at which it resides within the crust. Magma stored in deeper reservoirs tend to experience less pre-eruptive degassing and to be richer in volatiles than magma shallower reservoirs. Eruptive style is influenced by the rate at which a magma ascends from the reservoir to the surface through its effect on the efficiency of vapor bubble nucleation, growth, and coalescence. The proposed work will advance our understanding of pre-eruptive storage conditions and syn-eruptive ascent rates through a combined field and analytical research program. Volatile measurements from olivine-hosted melt inclusions will be used to systematically investigate magma storage depths and ascent rates associated with alkaline volcanism in the Erebus volcanic province. A central goal of the project is to provide a spatial and temporal framework for interpreting results from studies of present-day volcanic processes at Mt Erebus volcano. The Erebus volcanic province of Antarctica is especially well suited to this type of investigation because: (1) there are many exposed mafic scoria cones, fissure vents, and hyaloclastites (exposed in sea cliffs) that produced rapidly quenched, olivine-rich tephra; (2) existing volatile data for Ross Island MIs show that magma storage was relatively deep compared to many mafic volcanic systems; (3) some of the eruptive centers ejected mantle xenoliths, allowing for comparison of ascent rates for xenolith-bearing and xenolith-free eruptions, and comparison of ascent rates for those bearing xenoliths with times estimated from settling velocities; and (4) the cold, dry conditions in Antarctica result in excellent tephra preservation compared to tropical and even many temperate localities. The project provides new tools for assessing volcanic hazards, facilitates collaboration involving researchers from three different institutions (WHOI, U Wyoming, and U Oregon), supports the researchers\u0027 involvement in teaching, advising, and outreach, and provides an educational opportunity for a promising young postdoctoral researcher. Understanding the interrelationships among magma volatile contents, reservoir depths, and ascent rates is vital for assessing volcanic hazards associated with alkaline volcanism across the globe.", "east": 169.6, "geometry": "POINT(166.85 -77.775)", "instruments": null, "is_usap_dc": true, "keywords": "Tephra; Turtle Rock; USA/NSF; Amd/Us; LABORATORY; AMD; Ross Island; Turks Head; Hut Point Peninsula; LAVA SPEED/FLOW; USAP-DC; Mt. Morning; Mt. Terror; ROCKS/MINERALS/CRYSTALS; Mt. Bird; FIELD INVESTIGATION", "locations": "Ross Island; Mt. Morning; Mt. Bird; Mt. Terror; Hut Point Peninsula; Turtle Rock; Turks Head", "north": -77.1, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Gaetani, Glenn; Le Roux, Veronique; Sims, Kenneth; Wallace, Paul", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION; OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.45, "title": "Collaborative Research: Determining Magma Storage Depths and Ascent Rates for the Erebus Volcanic Province, Antarctica Using Diffusive Water Loss from Olivine-hosted Melt Inclusion", "uid": "p0010081", "west": 164.1}, {"awards": "1443296 Cottle, John", "bounds_geometry": "POLYGON((-180 -76.85314,-179.4383642 -76.85314,-178.8767284 -76.85314,-178.3150926 -76.85314,-177.7534568 -76.85314,-177.191821 -76.85314,-176.6301852 -76.85314,-176.0685494 -76.85314,-175.5069136 -76.85314,-174.9452778 -76.85314,-174.383642 -76.85314,-174.383642 -77.658865,-174.383642 -78.46459,-174.383642 -79.270315,-174.383642 -80.07604,-174.383642 -80.881765,-174.383642 -81.68749,-174.383642 -82.493215,-174.383642 -83.29894,-174.383642 -84.104665,-174.383642 -84.91039,-174.9452778 -84.91039,-175.5069136 -84.91039,-176.0685494 -84.91039,-176.6301852 -84.91039,-177.191821 -84.91039,-177.7534568 -84.91039,-178.3150926 -84.91039,-178.8767284 -84.91039,-179.4383642 -84.91039,180 -84.91039,177.4459565 -84.91039,174.891913 -84.91039,172.3378695 -84.91039,169.783826 -84.91039,167.2297825 -84.91039,164.675739 -84.91039,162.1216955 -84.91039,159.567652 -84.91039,157.0136085 -84.91039,154.459565 -84.91039,154.459565 -84.104665,154.459565 -83.29894,154.459565 -82.493215,154.459565 -81.68749,154.459565 -80.881765,154.459565 -80.07604,154.459565 -79.270315,154.459565 -78.46459,154.459565 -77.658865,154.459565 -76.85314,157.0136085 -76.85314,159.567652 -76.85314,162.1216955 -76.85314,164.675739 -76.85314,167.2297825 -76.85314,169.783826 -76.85314,172.3378695 -76.85314,174.891913 -76.85314,177.4459565 -76.85314,-180 -76.85314))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 02 Dec 2019 00:00:00 GMT", "description": "Subduction takes place at convergent plate boundaries and involves sinking of one tectonic plate underneath another. Although this process is a key aspect of plate tectonics that shapes the planet over geologic time, and is a primary cause of earthquakes, it is not known what causes subduction to cease, and what effect it has on the deepest portions of the crust and the upper part of the mantle. By studying the age and composition of igneous rocks emplaced at the very end of the subduction cycle, this project seeks to understand what causes subduction to cease, and how this changes the composition and structure of the crust and upper mantle. Because this process occurs deep within the earth, the project will focus on rocks in the root of an ancient subduction zone, now exposed in the Transantarctic Mountains of Antarctica. In addition, Antarctica remains relatively poorly understood, and this project will contribute directly to increasing our understanding of the geologic history of this region. The project will focus on training graduate and undergraduate students - incorporating hands-on experience with an array of state-of-the-art analytical instrumentation. Students will also gain a range of more general skills including Geographic Information Systems (GIS), written and oral communication, and data management - strengths that are highly relevant to careers both in the academic and Geosciences industry. Each summer, high school students will be incorporated into aspects of the laboratory-based research through the UCSB research mentorship program. The PI and graduate students will engage the general public through a purpose-built iPhone App and multimedia website. Activities will include live phone and video conversations from the field between elementary school students and members of the team in Antarctica. The mechanisms by which the deep crustal delaminates or \"founders\" and is returned to the mantle remains a fundamental problem in earth science. Specifically, little is known about the temporal and spatial scales over which this process occurs or the mechanisms that trigger such catastrophic events. Igneous rocks highly enriched in potassium, called lamprophyres, are often emplaced during, and immediately after, termination of subduction and therefore potentially provide direct insight into foundering. These enigmatic rocks are important because they represent near-primary mantle melt compositions and therefore their age, geochemistry and petrologic evolution reveal key information on both the composition of the upper mantle and its thermal state. Of equal importance, they reveal how these key parameters vary through both space and time. By evaluating lamprophyres along a subduction zone margin it is possible to extract: 1) local-scale information, such as the timing and duration of melting and the role of igneous crystallization processes in generation of isotopic heterogeneities; 2) along-strike variations in mantle source composition, temperature, and depth of melting 3) the plate-scale forces that control foundering and termination of subduction. This project will study a suite of lamprophyres along the axis of the Transantarctic Mountains, emplaced during the latest stages of the Neoproterozoic - Ordovician Ross orogeny, Antarctica (roughly 505 to 470 million years before present). High-precision geochronology (age determinations) will be combined with geochemical measurements on the rocks and minerals to understand the mechanisms and timing of deep crustal foundering/delamination.", "east": -174.383642, "geometry": "POINT(170.0379615 -80.881765)", "instruments": "NOT APPLICABLE \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "is_usap_dc": true, "keywords": "AGE DETERMINATIONS; ISOTOPES; PLATE TECTONICS; Antarctica; USAP-DC; NOT APPLICABLE", "locations": "Antarctica", "north": -76.85314, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Cottle, John", "platforms": "OTHER \u003e NOT APPLICABLE \u003e NOT APPLICABLE", "repositories": null, "science_programs": null, "south": -84.91039, "title": "Petrologic Constraints on Subduction Termination From Lamprophyres, Ross Orogen, Antarctica", "uid": "p0010071", "west": 154.459565}, {"awards": "1341390 Frank, Tracy", "bounds_geometry": null, "dataset_titles": "Stable carbon and oxygen isotope data from drill cores from McMurdo Sound, Antarctica", "datasets": [{"dataset_uid": "000195", "doi": "", "keywords": null, "people": null, "repository": "EarthChem", "science_program": null, "title": "Stable carbon and oxygen isotope data from drill cores from McMurdo Sound, Antarctica", "url": "http://dx.doi.org/10.1594/IEDA/100718"}], "date_created": "Fri, 06 Oct 2017 00:00:00 GMT", "description": "Intellectual Merit: This project will use sediment cores from the Victoria Land Basin (VLB), Antarctica, to study secondary (diagenetic) carbonate minerals, as indicators of the basin?s fluid-flow history, within the well-constrained tectonic, depositional, and climatic context provided by sediment cores. This study will provide insights into subsurface processes in Victoria Land Basin, Antarctica and their relationships with the region?s climatic, cryospheric, and tectonic history. The work will utilize cores previously recovered by US-sponsored stratigraphic drilling projects (CIROS, CRP, and ANDRILL projects). This work is motivated by the unexpected discovery of dense brine in the subsurface of Southern McMurdo Sound during drilling by the ANDRILL Southern McMurdo Sound project. The presence of the brine is intriguing because it contradicts previous models for the origin of subsurface fluids that called upon large contributions from glacial melt water. Project objectives involve documenting the distribution of the brine (and potentially other fluids) via characterization of diagenetic precipitates. The approach will involve integration of petrographic and geochemical data (including conventional carbon, oxygen, and ?clumped? isotopes) to fully characterize diagenetic phases and allow development of a robust paragenetic history. This work will provide novel insights into the Cenozoic evolution of the VLB and, more broadly, the role of glacial processes in generating subsurface fluids. Broader impacts: Results from this project will help understand the origins of brines, groundwater and hydrocarbon reservoirs in analogous modern and ancient deposits elsewhere, which is of broad interest. This project will support the training of one graduate and one undergraduate student at the University of Nebraska-Lincoln (UNL) providing learning opportunities in sedimentary geology and diagenesis, fields with wide applicability. This proposal emphasizes rapid dissemination of results to the scientific community via conference presentations and contributions to peer-reviewed publications. The results will be integrated into education activities designed to develop skills in petrography and diagenesis, which are highly sought after in the energy sector. The project will generate a well-constrained dataset that allows direct linkage of diagenetic phases to environmental and tectonic change across a large sedimentary basin which will provide the basis for a comprehensive case study in an upper-level course (Sedimentary Petrography and Diagenesis) at UNL. In addition, online exercises will be developed and submitted to an open-access site (SEPM Stratigraphy Web) dedicated to sedimentary geology.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Instrumentation and Support; Antarctic Earth Sciences", "paleo_time": null, "persons": "Frank, Tracy; Fielding, Christopher", "platforms": "Not provided", "repo": "EarthChem", "repositories": "EarthChem", "science_programs": null, "south": null, "title": "Insights into the Burial, Tectonic, and Hydrologic History of the Cenozoic Succession in McMurdo Sound, Antarctica through Analysis of Diagenetic Phases", "uid": "p0000256", "west": null}, {"awards": "1043619 Hemming, Sidney; 1043572 Licht, Kathy", "bounds_geometry": "POLYGON((-177.982 -63.997,-149.64107 -63.997,-121.30014 -63.997,-92.95921 -63.997,-64.61828 -63.997,-36.27735 -63.997,-7.93642 -63.997,20.40451 -63.997,48.74544 -63.997,77.08637 -63.997,105.4273 -63.997,105.4273 -66.3324,105.4273 -68.6678,105.4273 -71.0032,105.4273 -73.3386,105.4273 -75.674,105.4273 -78.0094,105.4273 -80.3448,105.4273 -82.6802,105.4273 -85.0156,105.4273 -87.351,77.08637 -87.351,48.74544 -87.351,20.40451 -87.351,-7.93642 -87.351,-36.27735 -87.351,-64.61828 -87.351,-92.95921 -87.351,-121.30014 -87.351,-149.64107 -87.351,-177.982 -87.351,-177.982 -85.0156,-177.982 -82.6802,-177.982 -80.3448,-177.982 -78.0094,-177.982 -75.674,-177.982 -73.3386,-177.982 -71.0032,-177.982 -68.6678,-177.982 -66.3324,-177.982 -63.997))", "dataset_titles": "East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains", "datasets": [{"dataset_uid": "600124", "doi": "10.15784/600124", "keywords": "Antarctica; East Antarctica; Geochemistry; Ross Sea; Sample/collection Description; Sample/Collection Description; Solid Earth; Southern Ocean; West Antarctica", "people": "Hemming, Sidney R.", "repository": "USAP-DC", "science_program": null, "title": "East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains", "url": "https://www.usap-dc.org/view/dataset/600124"}], "date_created": "Tue, 18 Feb 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. 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.", "east": 105.4273, "geometry": "POINT(-36.27735 -75.674)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e LA-ICP-MS; IN SITU/LABORATORY INSTRUMENTS \u003e PHOTON/OPTICAL DETECTORS \u003e PETROGRAPHIC MICROSCOPES; IN SITU/LABORATORY INSTRUMENTS \u003e SPECTROMETERS/RADIOMETERS \u003e ICP-MS", "is_usap_dc": true, "keywords": "Not provided; FIELD SURVEYS", "locations": null, "north": -63.997, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY", "persons": "Licht, Kathy; Hemming, Sidney R.", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS; Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -87.351, "title": "Collaborative Research: East Antarctic outlet glacier contributions to the Ross Sea from chronology of detrital grains", "uid": "p0000333", "west": -177.982}, {"awards": "0228842 Grew, Edward", "bounds_geometry": "POLYGON((76 -69.3,76.05 -69.3,76.1 -69.3,76.15 -69.3,76.2 -69.3,76.25 -69.3,76.3 -69.3,76.35 -69.3,76.4 -69.3,76.45 -69.3,76.5 -69.3,76.5 -69.32,76.5 -69.34,76.5 -69.36,76.5 -69.38,76.5 -69.4,76.5 -69.42,76.5 -69.44,76.5 -69.46,76.5 -69.48,76.5 -69.5,76.45 -69.5,76.4 -69.5,76.35 -69.5,76.3 -69.5,76.25 -69.5,76.2 -69.5,76.15 -69.5,76.1 -69.5,76.05 -69.5,76 -69.5,76 -69.48,76 -69.46,76 -69.44,76 -69.42,76 -69.4,76 -69.38,76 -69.36,76 -69.34,76 -69.32,76 -69.3))", "dataset_titles": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?", "datasets": [{"dataset_uid": "600030", "doi": "10.15784/600030", "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Geochemistry; Geochronology; Solid Earth", "people": "Grew, Edward", "repository": "USAP-DC", "science_program": null, "title": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?", "url": "https://www.usap-dc.org/view/dataset/600030"}], "date_created": "Tue, 10 Mar 2009 00:00:00 GMT", "description": "This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role and fate of Boron in high-grade metamorphic rocks of the Larsemann Hills region of Antarctica. Trace elements provide valuable information on the changes sedimentary rocks undergo as temperature and pressure increase during burial. One such element, boron, is particularly sensitive to increasing temperature because of its affinity for aqueous fluids, which are lost as rocks are buried. Boron contents of unmetamorphosed pelitic sediments range from 20 to over 200 parts per million, but rarely exceed 5 parts per million in rocks subjected to conditions of the middle and lower crust, that is, temperatures of 700 degrees C or more in the granulite-facies, which is characterized by very low water activities at pressures of 5 to 10 kbar (18-35 km burial). Devolatization reactions with loss of aqueous fluid and partial melting with removal of melt have been cited as primary causes for boron depletion under granulite-facies conditions. Despite the pervasiveness of both these processes, rocks rich in boron are locally found in the granulite-facies, that is, there are mechanisms for retaining boron during the metamorphic process. The Larsemann Hills, Prydz Bay, Antarctica, are a prime example. More than 20 lenses and layered bodies containing four borosilicate mineral species crop out over a 50 square kilometer area, which thus would be well suited for research on boron-rich granulite-facies metamorphic rocks. \u003cbr/\u003e\u003cbr/\u003eWhile most investigators have focused on the causes for loss of boron, this work will investigate how boron is retained during high-grade metamorphism. Field observations and mapping in the Larsemann Hills, chemical analyses of minerals and their host rocks, and microprobe age dating will be used to identify possible precursors and deduce how the precursor materials recrystallized into borosilicate rocks under granulite-facies conditions. The working hypothesis is that high initial boron content facilitates retention of boron during metamorphism because above a certain threshold boron content, a mechanism \"kicks in\" that facilitates retention of boron in metamorphosed rocks. For example, in a rock with large amounts of the borosilicate tourmaline, such as stratabound tourmalinite, the breakdown of tourmaline to melt could result in the formation of prismatine and grandidierite, two borosilicates found in the Larsemann Hills. This situation is rarely observed in rocks with modest boron content, in which breakdown of tourmaline releases boron into partial melts, which in turn remove boron when they leave the system. Stratabound tourmalinite is associated with manganese-rich quartzite, phosphorus-rich rocks and sulfide concentrations that could be diagnostic for recognizing a tourmalinite protolith in a highly metamorphosed complex where sedimentary features have been destroyed by deformation. Because partial melting plays an important role in the fate of boron during metamorphism, our field and laboratory research will focus on the relationship between the borosilicate units, granite pegmatites and other granitic intrusives. The results of our study will provide information on cycling of boron at deeper levels in the Earth\u0027s crust and on possible sources of boron for granites originating from deep-seated rocks.\u003cbr/\u003e\u003cbr/\u003eAn undergraduate student will participate in the electron microprobe age-dating of monazite and xenotime as part of a senior project, thereby integrating the proposed research into the educational mission of the University of Maine. In response to a proposal for fieldwork, the Australian Antarctic Division, which maintains Davis station near the Larsemann Hills, has indicated that they will support the Antarctic fieldwork.", "east": 76.5, "geometry": "POINT(76.25 -69.4)", "instruments": null, "is_usap_dc": true, "keywords": "FIELD INVESTIGATION", "locations": null, "north": -69.3, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Grew, Edward", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD INVESTIGATION", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -69.5, "title": "Boron in Antarctic granulite-facies rocks: under what conditions is boron retained in the middle crust?", "uid": "p0000431", "west": 76.0}, {"awards": "0087235 Grew, Edward", "bounds_geometry": "POLYGON((42 -64,43.2 -64,44.4 -64,45.6 -64,46.8 -64,48 -64,49.2 -64,50.4 -64,51.6 -64,52.8 -64,54 -64,54 -64.4,54 -64.8,54 -65.2,54 -65.6,54 -66,54 -66.4,54 -66.8,54 -67.2,54 -67.6,54 -68,52.8 -68,51.6 -68,50.4 -68,49.2 -68,48 -68,46.8 -68,45.6 -68,44.4 -68,43.2 -68,42 -68,42 -67.6,42 -67.2,42 -66.8,42 -66.4,42 -66,42 -65.6,42 -65.2,42 -64.8,42 -64.4,42 -64))", "dataset_titles": null, "datasets": null, "date_created": "Mon, 09 Aug 2004 00:00:00 GMT", "description": "0087235\u003cbr/\u003eGrew\u003cbr/\u003e\u003cbr/\u003eThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a project to investigate the role of beryllium in lower crustal partial melting events. The formation of granitic liquids by partial melting deep in the Earth\u0027s crust is one of the major topics of research in igneous and metamorphic petrology today. One aspect of this sphere of research is the beginning of the process, specifically, the geochemical interaction between melts and source rocks before the melt has left the source area. One example of anatexis in metamorphic rocks affected by conditions found deep in the Earth\u0027s crust is pegmatite in the Archean ultrahigh temperature granulite-facies Napier Complex of Enderby Land, East Antarctica. Peak conditions for this granulite-facies metamorphism are estimated to have reached nearly 1100 Degrees Celsius and 11 kilobar, that is, conditions in the Earth\u0027s lower crust in Archean time. The proposed research is a study of the Napier Complex pegmatites with an emphasis on the minerals and geochemistry of beryllium. This element, which is estimated to constitute 3 ppm of the Earth\u0027s upper crust, is very rarely found in any significant concentrations in metamorphic rocks subjected to conditions of the Earth\u0027s lower crust. Structural, geochronological, and mineralogical studies will be carried out to test the hypothesis that the beryllium pegmatites resulted from anatexis of their metapelitic host rocks during the ultrahigh-temperature metamorphic event in the late Archean. Host rocks will be analyzed for major and trace elements. Minerals will be analyzed by the electron microprobe for major constituents including fluorine and by the ion microprobe for lithium, beryllium and boron. The analytical data will be used to determine how beryllium and other trace constituents were extracted from host rocks under ultrahigh-temperature conditions and subsequently concentrated in the granitic melt, eventually to crystallize out in a pegmatite as beryllian sapphirine and khmaralite, minerals not found in pegmatites elsewhere. Mineral compositions and assemblages will be used to determine the evolution and conditions of crystallization and recrystallization of the pegmatites and their host rocks during metamorphic episodes following the ultrahigh-temperature event. Monazite will be analyzed for lead, thorium and uranium to date the ages of these events. Because fluorine is instrumental in mobilizing beryllium, an undergraduate student will study the magnesium fluorphosphate wagnerite in the pegmatites in order to estimate fluorine activity in the melt as part of a senior project. The results of the present project will provide important insights on the melting process in general and on the geochemical behavior of beryllium in particular under the high temperatures and low water activities characteristic of the Earth\u0027s lower crust.", "east": 54.0, "geometry": "POINT(48 -66)", "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e PROBES \u003e ELECTRON MICROPROBES; IN SITU/LABORATORY INSTRUMENTS \u003e PROBES \u003e ION MICROPROBES", "is_usap_dc": false, "keywords": "Metamorphism; Li; Be; Pegmatitic Leucosomes; Partial Melting; Lithium; Granulites; Napier Complex; Boron; Beryllium; Mineralogy; Not provided; Continental Crust", "locations": "Napier Complex", "north": -64.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Grew, Edward", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -68.0, "title": "Beryllium in Antarctic Ultrahigh-Temperature Granulite-Facies Rocks and its Role in Partial Melting of the Lower Continental Crust", "uid": "p0000370", "west": 42.0}]

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