Domack Eugene

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Domack
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Eugene
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  • Article
    Antarctic sediment chronology by programmed-temperature pyrolysis : methodology and data treatment
    (American Geophysical Union, 2008-04-02) Rosenheim, Brad E. ; Day, Mary Beth ; Domack, Eugene ; Schrum, Heather ; Benthien, Albert ; Hayes, John M.
    We report a detailed programmed-temperature pyrolysis/combustion methodology for radiocarbon (14C) dating of Antarctic sub-ice shelf sediments. The method targets the autochthonous organic component in sediments that contain a distribution of acid-insoluble organic components from several sources of different ages. The approach has improved sediment chronology in organic-rich sediments proximal to Antarctic ice shelves by yielding maximum age constraints significantly younger than bulk radiocarbon dates from the same sediment horizons. The method proves adequate in determining isotope ratios of the pre-aged carbon end-member; however, the isotopic compositions of the low-temperature measurements indicate that no samples completely avoided mixing with some proportion of pre-aged organic material. Dating the unresolved but desired young end-member must rely on indirect methods, but a simple mixing model cannot be developed without knowledge of the sedimentation rate or comparable constraints. A mathematical approach allowing for multiple mixing components yields a maximum likelihood age, a first-order approximation of the relative proportion of the autochthonous component, and the temperature at which allochthonous carbon begins to volatilize and mix with the autochthonous component. It is likely that our estimation of the cutoff temperature will be improved with knowledge of the pyrolysis kinetics of the major components. Chronology is improved relative to bulk acid-insoluble organic material ages from nine temperature interval dates down to two, but incorporation of inherently more pre-aged carbon in the first division becomes more apparent with fewer and larger temperature intervals.
  • Preprint
    Grounding-zone wedges and mega-scale glacial lineations in the Mertz Trough, East Antarctica
    ( 2016-11) McMullen, Kate ; Domack, Eugene ; Leventer, Amy ; Lavoie, Caroline ; Canals, Miquel
    Glacial erosion and deposition have shaped the Mertz Trough, East Antarctica, where seafloor grounding-zone wedges (GZWs) are associated with mega-scale glacial lineations (MSGLs) (McMullen et al. 2006). GZWs form along grounded glacial margins constrained by ice shelves during stillstands and consist of wedge-shaped glacially transported sediment (Powell & Domack 2002). MSGLs are parallel elongate bedforms that typically form in soft sediments beneath rapidly flowing ice streams (Clark 1993; Canals et al. 2000; Clark et al. 2003). They are found in glacial troughs, usually parallel to trough margins. MSGLs are generally 6 to >100 km long, 200–1300 m wide and spaced 0.3–5 km apart, crest-to-crest (Clark et al. 2003; McMullen et al. 2006).
  • Article
    Foehn winds link climate-driven warming to ice shelf evolution in Antarctica
    (John Wiley & Sons, 2015-11-03) Cape, Mattias R. ; Vernet, Maria ; Skvarca, Pedro ; Marinsek, Sebastian ; Scambos, Ted ; Domack, Eugene
    Rapid warming of the Antarctic Peninsula over the past several decades has led to extensive surface melting on its eastern side, and the disintegration of the Prince Gustav, Larsen A, and Larsen B ice shelves. The warming trend has been attributed to strengthening of circumpolar westerlies resulting from a positive trend in the Southern Annular Mode (SAM), which is thought to promote more frequent warm, dry, downsloping foehn winds along the lee, or eastern side, of the peninsula. We examined variability in foehn frequency and its relationship to temperature and patterns of synoptic-scale circulation using a multidecadal meteorological record from the Argentine station Matienzo, located between the Larsen A and B embayments. This record was further augmented with a network of six weather stations installed under the U.S. NSF LARsen Ice Shelf System, Antarctica, project. Significant warming was observed in all seasons at Matienzo, with the largest seasonal increase occurring in austral winter (+3.71°C between 1962–1972 and 1999–2010). Frequency and duration of foehn events were found to strongly influence regional temperature variability over hourly to seasonal time scales. Surface temperature and foehn winds were also sensitive to climate variability, with both variables exhibiting strong, positive correlations with the SAM index. Concomitant positive trends in foehn frequency, temperature, and SAM are present during austral summer, with sustained foehn events consistently associated with surface melting across the ice sheet and ice shelves. These observations support the notion that increased foehn frequency played a critical role in precipitating the collapse of the Larsen B ice shelf.
  • Article
    A new US polar research vessel for the twenty-first century
    (The Oceanography Society, 2012-09) Dunbar, Robert B. ; Alberts, Jon ; Ashjian, Carin J. ; Asper, Vernon L. ; Chayes, Dale ; Domack, Eugene ; Ducklow, Hugh W. ; Huber, Bruce ; Lawver, Lawrence ; Oliver, Daniel ; Russell, Doug ; Smith, Craig R. ; Vernet, Maria
    Scientific and political interests at the poles are significant and rapidly increasing, driven in part by the effects of climate change and emerging geopolitical realities. The polar regions provide important services to global ecosystems and humankind, ranging from food and energy to freshwater and biodiversity. Yet the poles are experiencing changes at rates that far outpace the rest of the planet. Coastal Arctic communities are impacted by climate change through coastal erosion, sea level rise, ice loss, and altered marine food webs, threatening the future of their subsistence lifestyle. Climate change has dramatically increased the melt rate of ice sheets and glaciers at both poles and has the potential to significantly raise sea level worldwide. Oil and gas drilling as well as transportation in the Arctic have reached all-time high levels, in part because of reduced sea ice cover. Tourism is a growing industry at both poles, bringing more than 20,000 tourists each year to the western Antarctic Peninsula alone. The collateral effects of human activities include the potential for pollution of the marine environment, particularly through spills of hydrocarbons. Our ability to understand the effects of such activities and mishaps is limited, particularly in ice-covered areas during winter.