USAP-DC

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

[{"awards": "1946326 Doran, Peter", "bounds_geometry": "POLYGON((161 -77.4,161.3 -77.4,161.6 -77.4,161.9 -77.4,162.2 -77.4,162.5 -77.4,162.8 -77.4,163.1 -77.4,163.4 -77.4,163.7 -77.4,164 -77.4,164 -77.46,164 -77.52,164 -77.58,164 -77.64,164 -77.7,164 -77.76,164 -77.82,164 -77.88,164 -77.94,164 -78,163.7 -78,163.4 -78,163.1 -78,162.8 -78,162.5 -78,162.2 -78,161.9 -78,161.6 -78,161.3 -78,161 -78,161 -77.94,161 -77.88,161 -77.82,161 -77.76,161 -77.7,161 -77.64,161 -77.58,161 -77.52,161 -77.46,161 -77.4))", "dataset_titles": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers: Infrared Stimulated Luminescence data; EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers: in situ 14C data", "datasets": [{"dataset_uid": "601520", "doi": "10.15784/601520", "keywords": "Antarctica; Sample/collection Description; Sample/Collection Description; Sample Location; Taylor Valley", "people": "Stone, Michael; Doran, Peter", "repository": "USAP-DC", "science_program": "LTER", "title": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers: Infrared Stimulated Luminescence data", "url": "https://www.usap-dc.org/view/dataset/601520"}, {"dataset_uid": "601521", "doi": "10.15784/601521", "keywords": "Antarctica; Carbon-14; Sample/collection Description; Sample/Collection Description; Sample Location; Taylor Valley", "people": "Stone, Michael; Doran, Peter", "repository": "USAP-DC", "science_program": null, "title": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers: in situ 14C data", "url": "https://www.usap-dc.org/view/dataset/601521"}], "date_created": "Mon, 31 Jan 2022 00:00:00 GMT", "description": "The closed basin lakes of Taylor Valley fluctuate in lake level, responding to the net balance of water gain and loss. Geomorphologic evidence suggests that past lake levels in Taylor Valley were once much higher than they are today. Past studies have largely targeted organic radiocarbon as a means for dating these past lake levels. However, an unconstrained radiocarbon reservoir effect in the region reduces the credibility of those data and the lake level chronologies they produce. Alternative geochronometers are therefore necessary to validify or augment the lake level records produced using organic radiocarbon. This research tests the overarching hypothesis that a multi-proxy geochronologic approach can constrain the timing of major changes in Taylor Valley lake levels. The goals of this study are to provide a coarse-scale absolute chronology for lake level fluctuation in Taylor Valley in order to test the validity of the lake level record hypothesized by the organic radiocarbon datasets, demonstrate that in situ 14C and OSL are effective means to understand the physical dynamics of ancient water bodies, and increase the current understanding of polar lacustrine and ice sheet responses to past and present climatic changes. ", "east": 164.0, "geometry": "POINT(162.5 -77.7)", "instruments": null, "is_usap_dc": true, "keywords": "FIELD SURVEYS; Amd/Us; Taylor Valley; AGE DETERMINATIONS; USA/NSF; AMD; USAP-DC", "locations": "Taylor Valley", "north": -77.4, "nsf_funding_programs": "Antarctic Integrated System Science; Antarctic Earth Sciences", "paleo_time": null, "persons": "Doran, Peter", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": "LTER", "south": -78.0, "title": "EAGER: Refining glacial lake history in Taylor Valley, East Antarctica with alternative geochronometers", "uid": "p0010294", "west": 161.0}, {"awards": "2039419 Swanger, Kate", "bounds_geometry": "POLYGON((161 -77.3,161.2 -77.3,161.4 -77.3,161.6 -77.3,161.8 -77.3,162 -77.3,162.2 -77.3,162.4 -77.3,162.6 -77.3,162.8 -77.3,163 -77.3,163 -77.35,163 -77.4,163 -77.45,163 -77.5,163 -77.55,163 -77.6,163 -77.65,163 -77.7,163 -77.75,163 -77.8,162.8 -77.8,162.6 -77.8,162.4 -77.8,162.2 -77.8,162 -77.8,161.8 -77.8,161.6 -77.8,161.4 -77.8,161.2 -77.8,161 -77.8,161 -77.75,161 -77.7,161 -77.65,161 -77.6,161 -77.55,161 -77.5,161 -77.45,161 -77.4,161 -77.35,161 -77.3))", "dataset_titles": null, "datasets": null, "date_created": "Thu, 16 Dec 2021 00:00:00 GMT", "description": "The McMurdo Dry Valleys are the largest ice-free region in Antarctica and home to a seasonally active hydrologic system, with streams and saline lakes. Streams are fed by summer meltwater from local glaciers and snowbanks. Therefore, streamflow is tied to summer climate conditions such as air temperatures, ground temperatures, winds, and incoming solar radiation. Based on 50 years of monitoring, summer stream activity has been observed to change, and it likely varied during the geologic past in response to regional climate change and fluctuating glaciers. Thus, deposits from these streams can address questions about past climate, meltwater, and lake level changes in this region. How did meltwater streamflow respond to past climate change? How did streamflow vary during periods of glacial advance and retreat? At what times did large lakes fill many of the valleys and what was their extent? The researchers plan to acquire a record of stream activity for the Dry Valleys that will span the three largest valleys and a time period of about 100,000 years. This record will come from a series of active and ancient alluvial fans that were deposited by streams as they flowed from valley sidewalls onto valley floors. The study will provide a long-term context with which to assess recent observed changes to stream activity and lake levels. The research will be led by two female mid-career investigators and contribute significantly to student research opportunities and education. The research will contribute to graduate and undergraduate education by including students in both field and laboratory research, as well as incorporating data and results into the classroom. The research will be disseminated to K-12 and non-scientific communities through outreach that includes professional development training for K-12 teachers in eastern Massachusetts, development of hands-on activities, visits to K-12 classrooms, and STEM education and literacy activities in North Carolina.\r\n\r\nThe PIs propose to constrain rates of fluvial deposition and periods of increased fluvial activity in the McMurdo Dry Valleys during the Holocene and late Pleistocene. During 50 years of hydrologic monitoring in the Dry Valleys, scientists have observed that streams exhibit significant response to summer conditions. Previous studies of glacial and lacustrine deposits indicate regional glacier advance in the Dry Valleys during recent interglacial periods and high lake levels during and after the Last Glacial Maximum (LGM), with potentially significant low and high stands during the Holocene. However, the geologic record of meltwater activity is poorly constrained. The PIs seek to develop the first spatially-extensive record of stream deposition in the Dry Valleys by analyzing and dating alluvial fans. Given that alluvial fans are deposited by summer meltwater streams in a relatively stable tectonic setting, this record will serve as a proxy of regional summer climate conditions. Meltwater streams are an important component of the regional hydrologic system, connecting glaciers to lakes and affecting ecosystems and soils. A record of fluvial deposition is key to understanding the relationship between past climate change and regional hydrology. The proposed research will include remote- and field-based mapping of alluvial fans, stream channels, and meltwater sources as well as modeling potential incoming solar radiation to the fans and moisture sources during the austral summer. In the field, the PIs will document stratigraphy, collect near-surface sediments from 25 fans across four valleys (Taylor, Pearse, Wright, and Victoria), and collect 2- to 3-m vertical cores of ice-cemented sediments from three alluvial fan complexes. The PIs will then conduct depositional dating of fluvial sands via optically stimulated luminescence, and analyze mineralogy and bulk major element chemistry with X-ray powder diffraction and X-ray fluorescence. From these analyses, the PIs propose to (1) determine the timing of local- to regional-scale periods of high fluvial deposition, (2) calculate depositional rates, and (3) constrain depositional environments and sediment provenance. Given that many of the alluvial fans occur below the hypothesized maximum extents of glacially-dammed lakes in Wright and Victoria valleys, detailed stratigraphy, sediment provenance, and OSL dating of these fans could shed light on ongoing debates regarding the timing and extent of LGM and post-LGM lakes. The work will support a postdoctoral researcher, a PhD student, and many undergraduate and master\u2019s students in cross-disciplinary research that spans stratigraphy, geochemistry, paleoclimatology and physics.", "east": 163.0, "geometry": "POINT(162 -77.55)", "instruments": null, "is_usap_dc": true, "keywords": "FIELD SURVEYS; Amd/Us; SEDIMENTS; USA/NSF; AMD; Dry Valleys; USAP-DC", "locations": "Dry Valleys", "north": -77.3, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Swanger, Kate", "platforms": "LAND-BASED PLATFORMS \u003e FIELD SITES \u003e FIELD SURVEYS", "repositories": null, "science_programs": null, "south": -77.8, "title": "Collaborative Research: Holocene and Late Pleistocene Stream Deposition in the McMurdo Dry Valleys, Antarctica as a Proxy for Glacial Meltwater and Paleoclimate", "uid": "p0010285", "west": 161.0}, {"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.\r\n\r\nPhysical 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": "0944282 Hasiotis, Stephen", "bounds_geometry": "POINT(175 -86)", "dataset_titles": "Paleoenvironmental and Paleoclimatic Analysis of the Beacon Supergroup, Beardmore Glacier Area, Central Transantarctic Mountains, Antarctica", "datasets": [{"dataset_uid": "600156", "doi": "10.15784/600156", "keywords": "Antarctica; Beardmore Glacier; Biota; Fossil; Paleoclimate; Sample/collection Description; Sample/Collection Description; Solid Earth; Transantarctic Mountains", "people": "Hasiotis, Stephen", "repository": "USAP-DC", "science_program": null, "title": "Paleoenvironmental and Paleoclimatic Analysis of the Beacon Supergroup, Beardmore Glacier Area, Central Transantarctic Mountains, Antarctica", "url": "https://www.usap-dc.org/view/dataset/600156"}], "date_created": "Fri, 03 Jun 2016 00:00:00 GMT", "description": "Intellectual Merit: \u003cbr/\u003eThis proposal will study the diversity, abundance, and tiering patterns of ichnofossils in continental and marine deposits of the Beacon Supergroup in the Beardmore Glacier Area (BGA). The PIs will focus on continental strata that contain a variety of ichnofossils and paleosols. Ichnofossils will be evaluated for their architectural and surficial morphologies, and will be compared to modern and ancient traces to interpret the tracemaker behavior and paleoenvironmental setting. Distribution of ichnofossils within these units may indicate the effect of lateral variability of pedogenesis, the magnitude and frequency of depositional events, and the amount of moisture within the sediment, as well as the effects of climate change. The paleoclimatic significance of ichnofossils will be determined by comparing the burrow size, occurrence, tiering, and pedogenic significance of ichnofossils in measured sections of stratigraphic units deposited during global warming and cooling episodes. Comparisons will be made between BGA formations to stratigraphically equivalent rocks deposited at low paleolatitudes with previously determined paleoclimatic settings. The objectives of this project are to address two major questions: what differences existed in ichnodiversity, abundance, and tiering in marine and continental deposits between high- and low-paleolatitudes, and was there a dearth of habitat usage in continental deposits during the late Paleozoic and Mesozoic, particularly in fluvial and lacustrine environments compared to the habitat usage in the marine realm at that time? \u003cbr/\u003e\u003cbr/\u003eBroader impacts: \u003cbr/\u003eThis study will enhance the ability to interpret paleoenvironments to the subenvironmental scale, understand the evolution of soil biota and ecosystems at high paleolatitudes, determine the role of organisms in soil formation at high paleolatitudes, explore the effects of climate change on the body size and diversity of organisms in the soil communities, and develop new tools to interpret paleoclimate in high latitudes. There is a strong education component associated with this proposal.", "east": 175.0, "geometry": "POINT(175 -86)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided", "locations": null, "north": -86.0, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Hasiotis, Stephen", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -86.0, "title": "Paleoenvironmental and Paleoclimatic Analysis of the Beacon Supergroup, Beardmore Glacier Area, Central Transantarctic Mountains, Antarctica", "uid": "p0000423", "west": 175.0}, {"awards": "0440711 Marchant, David", "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": "Wed, 01 Jul 2009 00:00:00 GMT", "description": "This project studies ancient lake deposits from the western Dry Valleys of Antarctica. These deposits are particularly exciting because they preserve flora and fauna over seven million years in age that represent the last vestiges of ecosystems that dominated this area before formation of the modern East Antarctic ice sheet. Their unique nature offers a chance to bridge modern and ancient ecology. Formed along the margin of ancient alpine glaciers, these deposits contain layers of silt, clay, and volcanic ash; as well as freeze-dried remnants of mosses, insects, and diatoms. Geological and biological analyses provide a view of the ecological and environmental conditions during mid-to-late Miocene--seven to seventeen million years ago--which spans the critical period when the East Antarctic ice sheet transitioned to its present stable form. The results place the modern lakes of the Dry Valleys into a long-term evolutionary framework, and allow for correlation and dating comparisons with other fossil-rich deposits from the Transantarctic Mountains. Chemical fingerprinting and dating of volcanic glass shards will also help date fossil- and ash-bearing horizons in nearby marine cores, such as those to be collected under the ANDRILL program. \u003cbr/\u003e\u003cbr/\u003eThe broader impacts are education at the postdoctoral, graduate, and undergraduate levels; and collaboration between a research institution and primarily undergraduate institution. The work also improves our understanding of global climate change during a critical period in the Earth\u0027s history.", "east": 164.5, "geometry": "POINT(162.25 -77.5)", "instruments": null, "is_usap_dc": false, "keywords": "Paleoclimate; Not provided; Lacustrine; Tundra; Middle Miocene; McMurdo Dry Valleys; Vegetation; Fossil; Antarctica", "locations": "Antarctica; McMurdo Dry Valleys", "north": -76.5, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": null, "persons": "Marchant, David", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": -78.5, "title": "Collaborative Research: Deducing Late Neogene Antarctic Climate from Fossil-Rich Lacustrine Sediments in the Dry Valleys", "uid": "p0000186", "west": 160.0}, {"awards": "0739693 Ashworth, Allan; 0739700 Marchant, David", "bounds_geometry": "POLYGON((160 -77,160.2 -77,160.4 -77,160.6 -77,160.8 -77,161 -77,161.2 -77,161.4 -77,161.6 -77,161.8 -77,162 -77,162 -77.1,162 -77.2,162 -77.3,162 -77.4,162 -77.5,162 -77.6,162 -77.7,162 -77.8,162 -77.9,162 -78,161.8 -78,161.6 -78,161.4 -78,161.2 -78,161 -78,160.8 -78,160.6 -78,160.4 -78,160.2 -78,160 -78,160 -77.9,160 -77.8,160 -77.7,160 -77.6,160 -77.5,160 -77.4,160 -77.3,160 -77.2,160 -77.1,160 -77))", "dataset_titles": "Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains", "datasets": [{"dataset_uid": "600081", "doi": "10.15784/600081", "keywords": "Antarctica; Geochronology; Geology/Geophysics - Other; GPS; Solid Earth", "people": "Lewis, Adam; Ashworth, Allan", "repository": "USAP-DC", "science_program": null, "title": "Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains", "url": "https://www.usap-dc.org/view/dataset/600081"}], "date_created": "Mon, 22 Jun 2009 00:00:00 GMT", "description": "This project studies the last vestiges of life in Antarctica from exceptionally well-preserved fossils of tundra life--mosses, diatoms, ostracods, Nothofagus leaves, wood, and insect remains recently discovered in ancient lake sediments from the McMurdo Dry Valleys. The area will be studied by an interdisciplinary team to elucidate information about climate and biogeography. These deposits offer unique and direct information about the characteristics of Antarctica during a key period in its history, the time when it was freezing. This information is critical for correlation with indirect proxies, such as though obtained from drill cores, for climate and state of the ice sheet. The results will also help understand the origin and migration of similar organisms found in South America, India and Australia.\u003cbr/\u003e\u003cbr/\u003eIn terms of broader impacts, this project supports an early career researcher, undergraduate and graduate student research, various forms of outreach to K12 students, and extensive international collaboration. The work also has societal relevance in that the outcomes will offer direct constraints on Antarctica\u0027s ice sheet during a time with atmospheric CO2 contents similar to those of the earth in the coming centuries, and thus may help predictive models of sea level rise.", "east": 162.0, "geometry": "POINT(161 -77.5)", "instruments": null, "is_usap_dc": true, "keywords": "Not provided; Antarctica; Vegetation; Paleoclimate; Middle Miocene; Tundra; Bu/es Data Repository; McMurdo Dry Valleys; Lacustrine; Fossil", "locations": "Antarctica; McMurdo Dry Valleys", "north": -77.0, "nsf_funding_programs": "Antarctic Earth Sciences; Antarctic Earth Sciences", "paleo_time": null, "persons": "Ashworth, Allan; Lewis, Adam", "platforms": "Not provided", "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -78.0, "title": "Collaborative Research: Integrating Geomorphological and Paleoecological Studies to Reconstruct Neogene Environments of the Transantarctic Mountains", "uid": "p0000188", "west": 160.0}, {"awards": "0126270 Doran, Peter", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Mon, 05 Feb 2007 00:00:00 GMT", "description": "Polar Programs, provides funds for a study of sediment cores from the McMurdo Dry Valley lakes. The Dry Valley lakes have a long history of fluctuating levels reflecting regional climate change. The history of lake level fluctuations is generally known from the LGM to early Holocene through 14C dates of buried organic matter in paleolake deposits. However, the youngest paleolake deposits available are between 8000 to 9000 14C yr BP, suggesting that lake levels were at or below current levels for much of the Holocene. Thus, any information about the lake history and climate controls for the Holocene is largely contained in bottom sediments. This project will attempt to extract paleoclimatic information from sediment cores for a series of closed-basin dry valley lakes under study by the McMurdo LTER site. This work involves multiple approaches to dating the sediments and use of several climate proxy approaches to extract century to millennial scale chronologies from Antarctic lacustrine deposits. This research uses knowledge on lake processes gained over the past eight years by the LTER to calibrate climate proxies from lake sediments. Proxies for lake depth and ice thickness, which are largely controlled by summer climate, are the focus of this work. This study focuses on four key questions: 1. How sensitively do dry valley lake sediments record Holocene environmental and climate variability? 2. What is the paleoclimatic variability in the dry valleys on a century and millennial scale throughout the Holocene? Especially, is the 1200 yr evaporative event unique, or are there other such events in the record? 3. Does a mid-Holocene (7000 to 5000 yr BP) climate shift occur in the dry valleys as documented elsewhere in the polar regions? 4. Is there evidence, in the dry valley lake record of the 1500 yr Holocene periodicities recently recognized in the Taylor Dome record? Core collection will be performed with LTER support using a state-of-the-art percussion/piston corer system that has been used successfully to retrieve long cores (10 to 20 m) from other remote polar locations. Analyses to be done include algal pigments, biogenic silica, basic geochemistry, organic and inorganic carbon and nitrogen content, stable isotopes of carbon, nitrogen, and oxygen, carbonate phases, salt content and mineralogy, and grain size. In addition this project will pursue a multi-chronometer approach to assess the age of the core through optically-stimulated luminescence, 226Ra/230Th , 230Th/234U, and 14C techniques. New experimentation with U-series techniques will be performed to allow for greater precision in the dry valley lake sediments. Compound specific isotopes and lipid biomarkers , which are powerful tools for inferring past lake conditions, will also be assessed. Combined, these analyses will provide a new century to millennial scale continuous record of the Holocene climate change in the Ross Sea region.", "east": null, "geometry": null, "instruments": "IN SITU/LABORATORY INSTRUMENTS \u003e CORERS \u003e SEDIMENT CORERS", "is_usap_dc": false, "keywords": "Not provided", "locations": null, "north": null, "nsf_funding_programs": "Antarctic Earth Sciences", "paleo_time": "PHANEROZOIC \u003e CENOZOIC \u003e QUATERNARY", "persons": "Doran, Peter", "platforms": "Not provided", "repositories": null, "science_programs": null, "south": null, "title": "Paleoclimate Inferred from Lake Sediment Cores in Taylor Valley, Antarctica", "uid": "p0000092", "west": null}]

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