Leventer Amy

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  • Article
    Scientific access into Mercer Subglacial Lake: scientific objectives, drilling operations and initial observations
    (Cambridge University Press, 2021-01-08) Priscu, John C. ; Kalin, Jonas ; Winans, John ; Campbell, Timothy ; Siegfried, Matthew R. ; Skidmore, Mark ; Dore, John E. ; Leventer, Amy ; Harwood, David M. ; Duling, Dennis ; Zook, Robert ; Burnett, Justin ; Gibson, Dar ; Krula, Edward ; Mironov, Anatoly ; McManis, James ; Roberts, Graham ; Rosenheim, Brad E. ; Christner, Brent C. ; Kasic, Kathy ; Fricker, Helen A. ; Lyons, W. Berry ; Barker, Joel ; Bowling, Mark ; Collins, Billy ; Davis, Christina ; Gagnon, Alan R. ; Gardner, Christopher B. ; Gustafson, Chloe ; Kim, Ok-Sun ; Li, Wei ; Michaud, Alex ; Patterson, Molly O. ; Tranter, Martyn ; Venturelli, Ryan ; Vick-Majors, Trista ; Elsworth, Cooper
    The Subglacial Antarctic Lakes Scientific Access (SALSA) Project accessed Mercer Subglacial Lake using environmentally clean hot-water drilling to examine interactions among ice, water, sediment, rock, microbes and carbon reservoirs within the lake water column and underlying sediments. A ~0.4 m diameter borehole was melted through 1087 m of ice and maintained over ~10 days, allowing observation of ice properties and collection of water and sediment with various tools. Over this period, SALSA collected: 60 L of lake water and 10 L of deep borehole water; microbes >0.2 μm in diameter from in situ filtration of ~100 L of lake water; 10 multicores 0.32–0.49 m long; 1.0 and 1.76 m long gravity cores; three conductivity–temperature–depth profiles of borehole and lake water; five discrete depth current meter measurements in the lake and images of ice, the lake water–ice interface and lake sediments. Temperature and conductivity data showed the hydrodynamic character of water mixing between the borehole and lake after entry. Models simulating melting of the ~6 m thick basal accreted ice layer imply that debris fall-out through the ~15 m water column to the lake sediments from borehole melting had little effect on the stratigraphy of surficial sediment cores.
  • 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).