USAP-DC

{"dp_type": "Project", "free_text": "MAJOR ELEMENTS"}

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J.; Marks Peterson, Julia", "repository": "USAP-DC", "science_program": "COLDEX", "title": "ALHIC2201 and ALHIC2302 3D ECM and Layer Orientations", "url": "https://www.usap-dc.org/view/dataset/601854"}], "date_created": "Sun, 07 Aug 2022 00:00:00 GMT", "description": "Ice cores provide valuable records of past climate such as atmospheric concentrations of greenhouse gasses and unmatched evidence of past abrupt climate change. Key to understanding past climate changes are the measurements of annual layers that are used to determine the age of the ice, and the timing and pace of major climate events. The current measurement limit for annual layers in ice cores is at the centimeter scale. This project aims to improve the depth resolution of measurements of the chemical impurities in ice using measurements such as electrical conductivity, hyperspectral imaging, major elements measured with laser ablation, and ice grain properties. This will advance understanding of the preservation and layering in ice cores and improve the accuracy and length of annual timescales for existing ice cores. Most of the past time preserved in an ice core is near the bed where the layers have been thinned to only a fraction of their original thickness. Interpreting highly compressed portions of ice cores is increasingly important as projects target climate records in basal ice, and old ice recovered from blue-ice areas. This project will integrate precisely co-registered electrical conductivity measurements, hyperspectral imaging, laser ablation mass spectrometer measurements of impurities, and ice physical properties to investigate sub-centimeter chemical and physical variations in polar ice. Critical to resolving thin ice layers is understanding the across-core variations that may obscure or distort the vertical layering. Analyses will be focused on samples from the WDC-06A (WAIS Divide), SPC-14 (South Pole), and GISP2 (Greenland Ice Sheet Project 2) ice cores that have well-established seasonal cycles that yielded benchmark timescales, as well a large-diameter ice core from the Allan Hills blue ice area. This work will develop state-of-the-art instrumentation and FAIR (findable, accessible, interoperable, and reusable) data handling workflow at the National Science Foundation Ice Core Facility available to the community both to enhance understanding of existing ice cores, and for use in future projects. 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": "ICE CORE RECORDS; Ice Core", "locations": null, "north": -60.0, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Fudge, T. J.; Fegyveresi, John M", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -90.0, "title": "Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections", "uid": "p0010365", "west": -180.0}, {"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": "1644171 Blackburn, Terrence", "bounds_geometry": "POLYGON((162 -77.5,162.2 -77.5,162.4 -77.5,162.6 -77.5,162.8 -77.5,163 -77.5,163.2 -77.5,163.4 -77.5,163.6 -77.5,163.8 -77.5,164 -77.5,164 -77.525,164 -77.55,164 -77.575,164 -77.6,164 -77.625,164 -77.65,164 -77.675,164 -77.7,164 -77.725,164 -77.75,163.8 -77.75,163.6 -77.75,163.4 -77.75,163.2 -77.75,163 -77.75,162.8 -77.75,162.6 -77.75,162.4 -77.75,162.2 -77.75,162 -77.75,162 -77.725,162 -77.7,162 -77.675,162 -77.65,162 -77.625,162 -77.6,162 -77.575,162 -77.55,162 -77.525,162 -77.5))", "dataset_titles": "Isotopic ratios for subglacial precipitates from East Antarctica; U-Th isotopes and major elements in sediments from Taylor Valley, Antarctica", "datasets": [{"dataset_uid": "601806", "doi": "10.15784/601806", "keywords": "Antarctica; Cryosphere; Erosion; Isotope Data; Major Elements; Soil; Taylor Glacier; Taylor Valley", "people": "Piccione, Gavin; Tulaczyk, Slawek; Blackburn, Terrence; Edwards, Graham", "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"}, {"dataset_uid": "200240", "doi": "10.26022/IEDA/111548 ", "keywords": null, "people": null, "repository": "EarthChem", "science_program": null, "title": "Isotopic ratios for subglacial precipitates from East Antarctica", "url": "https://doi.org/10.26022/IEDA/111548"}], "date_created": "Fri, 13 Aug 2021 00:00:00 GMT", "description": "A\u00a0nontechnical\u00a0description of the project The primary scientific goal of the project is to test whether Taylor Valley, Antarctica has been eroded significantly by glaciers in the last ~2 million years (Ma). Taylor Valley is one of the Dry Valleys of the Transantarctic Mountains, which are characterized by low mean annual temperatures, low precipitation, and limited erosion. These conditions have allowed fragile glacial landforms to be preserved for up to 15 Ma. Sediment eroded and deposited by glaciers is found on the valley walls and floors, with progressively younger deposits preserved at lower elevations. Scientists can date glacial deposits to understand the process and timing of past glacial erosion. Previous work in the Dry Valleys region suggested that extremely cold glaciers like Taylor Glacier, a major outlet glacier entering the valleys, were not erosive during the last several million years. This research will test a new hypothesis that glacial erosion and sediment production beneath Taylor Glacier have been active in the last few million years. This hypothesis will be tested using a new isotopic dating method called \"comminution dating\u0027 which determines when fine-grained sediment particles called silt were formed. If the sediment age is young, then the results will suggest that glacial processes have been more dynamic than previously thought. Overall, this study will increase our understanding of the nature and extent of past glaciations in Antarctica. Because the silt produced by erosion sediment is a nutrient for local ecosystems, the results will also shed light on delivery of nutrients to soils, streams, and coastal zones in high polar regions. This project will be led by an early career scientist and includes training of a Ph.D. student. A\u00a0technical description of the project There is a long-standing scientific controversy about the stability of the East Antarctic Ice Sheet with much evidence centered in the Dry Valleys region of South Victoria Land. A prevailing view of geomorphologists is that the landscape has been very stable and that the effects of glaciation have been minimal for the past ~15 Ma. This project will distinguish between two end-member scenarios of glacial erosion and deposition by Taylor Glacier, an outlet glacier of the East Antarctic Ice Sheet that terminates in Taylor Valley in the Dry Valleys region of Antarctica. In the first scenario, all valley relief is generated prior to 15 Ma when non-polar climates enabled warm-based glaciers to incise and widen ancient river channels. In this case, younger glacial deposits record advances of cold-based glaciers of decreasing ice volume and limited glacial erosion, and sediment generation resulted in glacial deposits composed primarily of older recycled sediments. In the second scenario, selective erosion of the valley floor has continued to deepen Taylor Valley but has not affected the adjacent peaks over the last 2 Ma. In this scenario, the \"bathtub rings\" of Quaternary glacial deposits situated at progressively lower elevations through time could be due to the lowering of the valley floor by subglacial erosion and with it, production of new sediment which is now incorporated into these deposits. While either scenario would result in the present-day topography, they differ in the implied evolution of regional glacial ice volume over time and the timing of both valley relief production and generation of fine-grained particles. The two scenarios will be tested by placing time constraints on fine particle production using U-series comminution dating. This new geochronologic tool exploits the loss of 234U due to alpha-recoil. The deficiency in 234U only becomes detectable in fine-grained particles with a sufficiently high surface-area-to-volume ratio which can incur appreciable 234U loss. The timing of comminution and particle size controls the magnitude of 234U loss. While this geochronologic tool is in its infancy, the scientific goal of this proposal can be achieved by resolving between ancient and recently comminuted fine particles, a binary question that the preliminary modeling and measured data show is readily resolved.", "east": 164.0, "geometry": "POINT(163 -77.625)", "instruments": null, "is_usap_dc": true, "keywords": "ICE SHEETS; Taylor Valley", "locations": "Taylor Valley", "north": -77.5, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Blackburn, Terrence; Tulaczyk, Slawek", "platforms": null, "repo": "USAP-DC", "repositories": "EarthChem; USAP-DC", "science_programs": null, "south": -77.75, "title": "U-Series Comminution Age Constraints on Taylor Valley Erosion", "uid": "p0010243", "west": 162.0}, {"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": "601594", "doi": "10.15784/601594", "keywords": "Antarctica; East Antarctica", "people": "Piccione, Gavin; Blackburn, Terrence", "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": "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": "601806", "doi": "10.15784/601806", "keywords": "Antarctica; Cryosphere; Erosion; Isotope Data; Major Elements; Soil; Taylor Glacier; Taylor Valley", "people": "Piccione, Gavin; Tulaczyk, Slawek; Blackburn, Terrence; Edwards, Graham", "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": "1443576 Panter, Kurt", "bounds_geometry": "POLYGON((-154.1 -86.9,-154.03 -86.9,-153.96 -86.9,-153.89 -86.9,-153.82 -86.9,-153.75 -86.9,-153.68 -86.9,-153.61 -86.9,-153.54 -86.9,-153.47 -86.9,-153.4 -86.9,-153.4 -86.92,-153.4 -86.94,-153.4 -86.96,-153.4 -86.98,-153.4 -87,-153.4 -87.02,-153.4 -87.04,-153.4 -87.06,-153.4 -87.08,-153.4 -87.1,-153.47 -87.1,-153.54 -87.1,-153.61 -87.1,-153.68 -87.1,-153.75 -87.1,-153.82 -87.1,-153.89 -87.1,-153.96 -87.1,-154.03 -87.1,-154.1 -87.1,-154.1 -87.08,-154.1 -87.06,-154.1 -87.04,-154.1 -87.02,-154.1 -87,-154.1 -86.98,-154.1 -86.96,-154.1 -86.94,-154.1 -86.92,-154.1 -86.9))", "dataset_titles": "Volcanological and Petrological measurements on Mt. Early and Sheridan Bluff volcanoes, upper Scott Glacier, Antarctica ", "datasets": [{"dataset_uid": "601331", "doi": "10.15784/601331", "keywords": "Antarctica; Chemistry:rock; Chemistry:Rock; Geochronology; Glacial Volcanism; Magma Differentiation; Major Elements; Mantle Melting; Solid Earth; Trace Elements; Transantarctic Mountains", "people": "Panter, Kurt", "repository": "USAP-DC", "science_program": null, "title": "Volcanological and Petrological measurements on Mt. Early and Sheridan Bluff volcanoes, upper Scott Glacier, Antarctica ", "url": "https://www.usap-dc.org/view/dataset/601331"}], "date_created": "Fri, 05 Jun 2020 00:00:00 GMT", "description": "Predictions of future sea level rise require better understanding of the changing dynamics of the Greenland and Antarctic ice sheets. One way to better understand the past history of the ice sheets is to obtain records from inland ice for past geological periods, particularly in Antarctica, the world?s largest remaining ice sheet. Such records are exceedingly rare, and can be acquired at volcanic outcrops in the La Gorce Mountains of the central Transantarctic Mountains. Volcanoes now exposed within the La Gorce Mountains erupted beneath the East Antarctic ice sheet and the data collected will record how thick the ice sheet was in the past. In addition, information will be used to determine the thermal conditions at the base of the ice sheet, which impacts ice sheet stability. The project will also investigate the origin of volcanic activity in Antarctica and links to the West Antarctic Rift System (WARS). The WARS is a broad area of extended (i.e. stretched) continental crust, similar to that found in East Africa, and volcanism is wide spread and long-lived (65 million years to currently active) and despite more than 50 years of research, the fundamental cause of volcanism and rifting in Antarctica is still vigorously debated. The results of this award therefore also potentially impact the study of oceanic volcanism in the entire southwestern Pacific region (e.g., New Zealand and Australia), where volcanic fields of similar composition and age have been linked by common magma sources and processes. The field program includes a graduate student who will work on the collection, analysis, and interpretation of petrological data as part of his/her Masters project. The experience and specialized analytical training being offered will improve the quality of the student?s research and optimize their opportunities for their future. The proposed work fosters faculty and student national and international collaboration, including working with multi-user facilities that provide advanced technological mentoring of science students. Results will be broadly disseminated in peer-reviewed journals, public presentations at science meetings, and in outreach activities. Petrologic and geochemical data will be disseminated to be the community through the Polar Rock Repository. The study of subglacially erupted volcanic rocks has been developed to the extent that it is now the most powerful proxy methodology for establishing precise ?snapshots? of ice sheets, including multiple critical ice parameters. Such data should include measurements of ice thickness, surface elevation and stability, which will be used to verify, or reject, published semi-empirical models relating ice dynamics to sea level changes. In addition to establishing whether East Antarctic ice was present during the formation of the volcanoes, data will be used to derive the coeval ice thicknesses, surface elevations and basal thermal regime(s) in concert with a precise new geochronology using the 40Ar/39Ar dating method. Inferences from measurement of standard geochemical characteristics (major, trace elements and Sr, Nd, Pb, O isotopes) will be used to investigate a possible relationship between the volcanoes and the recently discovered subglacial ridge under the East Antarctic ice, which may be a rift flank uplift. The ridge has never been sampled, is undated and its significance is uncertain. The data will provide important new information about the deep Earth and geodynamic processes beneath this mostly ice covered and poorly understood sector of the Antarctic continent.", "east": -153.4, "geometry": "POINT(-153.75 -87)", "instruments": null, "is_usap_dc": true, "keywords": "FIELD INVESTIGATION; Mantle Melting; Magma Differentiation; Geochronology; Glacial Volcanism; GEOCHEMISTRY; Major Elements; ISOTOPES; Trace Elements; Transantarctic Mountains; LABORATORY; LAVA COMPOSITION/TEXTURE; USAP-DC; LAND RECORDS", "locations": "Transantarctic Mountains", "north": -86.9, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Panter, Kurt", "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": -87.1, "title": "Investigating Early Miocene Sub-ice Volcanoes in Antarctica for Improved Modeling and understanding of a Large Magmatic Province", "uid": "p0010105", "west": -154.1}, {"awards": "0944615 Brown, Michael; 0944600 Siddoway, Christine", "bounds_geometry": "POLYGON((-146.5 -76,-145.95 -76,-145.4 -76,-144.85 -76,-144.3 -76,-143.75 -76,-143.2 -76,-142.65 -76,-142.1 -76,-141.55 -76,-141 -76,-141 -76.15,-141 -76.3,-141 -76.45,-141 -76.6,-141 -76.75,-141 -76.9,-141 -77.05,-141 -77.2,-141 -77.35,-141 -77.5,-141.55 -77.5,-142.1 -77.5,-142.65 -77.5,-143.2 -77.5,-143.75 -77.5,-144.3 -77.5,-144.85 -77.5,-145.4 -77.5,-145.95 -77.5,-146.5 -77.5,-146.5 -77.35,-146.5 -77.2,-146.5 -77.05,-146.5 -76.9,-146.5 -76.75,-146.5 -76.6,-146.5 -76.45,-146.5 -76.3,-146.5 -76.15,-146.5 -76))", "dataset_titles": "Rock Samples collected from bedrock exposures, Ford Ranges, MBL", "datasets": [{"dataset_uid": "200415", "doi": "", "keywords": null, "people": null, "repository": "Polar Rock Repository", "science_program": null, "title": "Rock Samples collected from bedrock exposures, Ford Ranges, MBL", "url": "http://bprc.osu.edu/rr/"}], "date_created": "Thu, 09 Oct 2014 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eThe northern Ford ranges in Marie Byrd Land, Antarctica, record events and processes that transformed a voluminous succession of Lower Paleozoic turbidites intruded by calc-alkaline plutonic rocks into differentiated continental crust along the margin of Gondwana. In this study the Fosdick migmatite?granite complex will be used to investigate crustal evolution through an integrated program of fieldwork, structural geology, petrology, mineral equilibria modeling, geochronology and geochemistry. The PIs propose detailed traverses at four sites within the complex to investigate Paleozoic and Mesozoic orogenic cycles. They will use petrological associations, structural geometry, and microstructures of host gneisses and leucogranites to distinguish the migration and coalescence patterns for remnant melt flow networks, and carry out detailed sampling for geochronology, geochemistry and isotope research. Mafic plutonic phases will be sampled to acquire information about mantle contributions at the source. Mineral equilibria modeling of source rocks and granite products, combined with in situ mineral dating, will be employed to resolve the P?T?t trajectories arising from thickening/thinning of crust during orogenic cycles and to investigate melting and melt loss history. \u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis work involves research and educational initiatives for an early career female scientist, as well as Ph.D. and undergraduate students. Educational programs for high school audiences and undergraduate courses on interdisciplinary Antarctic science will be developed.", "east": -141.0, "geometry": "POINT(-143.75 -76.75)", "instruments": null, "is_usap_dc": true, "keywords": "Tectonic; TECTONICS; Transcurrent Faults; MAJOR ELEMENTS; Migmatite; Structural Geology; Gneiss Dome; Geochronology; AGE DETERMINATIONS; Detachment Faults; Marie Byrd Land", "locations": "Marie Byrd Land", "north": -76.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Siddoway, Christine; Brown, Mike", "platforms": null, "repo": "Polar Rock Repository", "repositories": "Polar Rock Repository", "science_programs": null, "south": -77.5, "title": "Collaborative research: Polyphase Orogenesis and Crustal Differentiation in West Antarctica", "uid": "p0000259", "west": -146.5}]

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