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dc.contributor.authorLinhoff, Benjamin S.  Concept link
dc.contributor.authorCharette, Matthew A.  Concept link
dc.contributor.authorNienow, Peter W.  Concept link
dc.contributor.authorWadham, Jemma L.  Concept link
dc.contributor.authorTedstone, Andrew  Concept link
dc.contributor.authorCowton, Thomas  Concept link
dc.date.accessioned2017-04-19T18:19:00Z
dc.date.available2017-04-19T18:19:00Z
dc.date.issued2017-01-23
dc.identifier.citationEarth and Planetary Science Letters 462 (2017): 180-188en_US
dc.identifier.urihttps://hdl.handle.net/1912/8924
dc.descriptionThis paper is not subject to U.S. copyright. The definitive version was published in Earth and Planetary Science Letters 462 (2017): 180-188, doi:10.1016/j.epsl.2016.12.039.en_US
dc.description.abstractWater flow beneath the Greenland Ice Sheet (GrIS) has been shown to include slow-inefficient (distributed) and fast-efficient (channelized) drainage systems, in response to meltwater delivery to the bed via both moulins and surface lake drainage. This partitioning between channelized and distributed drainage systems is difficult to quantify yet it plays an important role in bulk meltwater chemistry and glacial velocity, and thus subglacial erosion. Radon-222, which is continuously produced via the decay of 226Ra, accumulates in meltwater that has interacted with rock and sediment. Hence, elevated concentrations of 222Rn should be indicative of meltwater that has flowed through a distributed drainage system network. In the spring and summer of 2011 and 2012, we made hourly 222Rn measurements in the proglacial river of a large outlet glacier of the GrIS (Leverett Glacier, SW Greenland). Radon-222 activities were highest in the early melt season (10–15 dpm L−1), decreasing by a factor of 2–5 (3–5 dpm L−1) following the onset of widespread surface melt. Using a 222Rn mass balance model, we estimate that, on average, greater than 90% of the river 222Rn was sourced from distributed system meltwater. The distributed system 222Rn flux varied on diurnal, weekly, and seasonal time scales with highest fluxes generally occurring on the falling limb of the hydrograph and during expansion of the channelized drainage system. Using laboratory based estimates of distributed system 222Rn, the distributed system water flux generally ranged between 1–5% of the total proglacial river discharge for both seasons. This study provides a promising new method for hydrograph separation in glacial watersheds and for estimating the timing and magnitude of distributed system fluxes expelled at ice sheet margins.en_US
dc.description.sponsorshipU.S. National Science Foundation Arctic Natural Sciences Program (ANS-1256669); Woods Hole Oceanographic Institution Arctic Research Initiative, Ocean Ventures Fund, and Ocean Climate Change Institute; United Kingdom Natural Environment Research Council studentship (NE/152830X/1); the Carnegie Trust, Edinburgh University Development Trust.en_US
dc.language.isoen_USen_US
dc.publisherElsevieren_US
dc.relation.urihttps://doi.org/10.1016/j.epsl.2016.12.039
dc.subjectRadonen_US
dc.subjectGreenlanden_US
dc.subjectGlacieren_US
dc.subjectProglacial riveren_US
dc.subjectMeltwateren_US
dc.titleUtility of Rn-222 as a passive tracer of subglacial distributed system drainageen_US
dc.typeArticleen_US
dc.identifier.doi10.1016/j.epsl.2016.12.039


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