Noble gas signatures in Greenland: Tracing glacial meltwater sources

Niu, Yi; Castro, Maria Clara; Aciego, S.; Hall, Chris M.; Stevenson, Emily; Arendt, Carli A.; Das, Sarah B.

doi:10.1002/2015gl065778

Cited by 9 publications

(7 citation statements)

References 48 publications

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“…Further, noble gas concentrations can provide insights into the temperature of recharge that can be used to approximate recharge elevations using local lapse rates (Niu, Castro, Hall, Gingerich, et al, ; Peters et al, ; Warrier et al, ). Noble‐gas‐based approaches have been applied to mountain glaciers (Niu, Castro, Hall, Aciego, et al, ) and ice sheets (Niu et al, ) to understand meltwater sources and flow paths. Further comparison of noble gas versus stable‐isotope approaches may help hone recharge elevation assessments and better understand englacial hydrology (Chu, ; L.C.…”

Section: Recharge Sources and Elevationsmentioning

confidence: 99%

Global Isotope Hydrogeology―Review

Jasechko

2019

Reviews of Geophysics

230

124

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Groundwater 18O/16O, 2H/1H, 13C/12C, 3H, and 14C data can help quantify molecular movements and chemical reactions governing groundwater recharge, quality, storage, flow, and discharge. Here, commonly applied approaches to isotopic data analysis are reviewed, involving groundwater recharge seasonality, recharge elevations, groundwater ages, paleoclimate conditions, and groundwater discharge. Reviewed works confirm and quantify long held tenets: (i) that recharge derives disproportionately from wet season and winter precipitation; (ii) that modern groundwaters comprise little global groundwater; (iii) that “fossil” (>12,000‐year‐old) groundwaters dominate global aquifer storage; (iv) that fossil groundwaters capture late‐Pleistocene climate conditions; (v) that surface‐borne contaminants are more common in younger groundwaters; and (vi) that groundwater discharges generate substantial streamflow. Groundwater isotope data are disproportionately common to midlatitudes and sedimentary basins equipped for irrigated agriculture, but less plentiful across high latitudes, hyperarid deserts, and equatorial rainforests. Some of these underexplored aquifer systems may be suitable targets for future field testing.

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Section: Recharge Sources and Elevationsmentioning

confidence: 99%

Global Isotope Hydrogeology―Review

Jasechko

2019

Reviews of Geophysics

230

124

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“…This approach assumes that distributed system meltwaters originate from material similar to the proglacial sediments we used to estimate Rn dis (Sections 2.4 and 3.4), and that the transit time of distributed system meltwaters are >20 days (Niu et al, 2015). able to obtain samples of distributed system water directly via borehole sampling (Tranter et al, 1997;Andrews et al, 2014), these estimates of Q dis carry significant uncertainty; therefore, we will use J dis for determining the timing and relative magnitude of distributed system fluxes.…”

Section: Quantifying the Distributed System Fluxmentioning

confidence: 99%

Utility of 222Rn as a passive tracer of subglacial distributed system drainage

Linhoff

Charette

Nienow

et al. 2017

Earth and Planetary Science Letters

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Keywords: radon Greenland glacier proglacial river meltwater Water 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 226 Ra, accumulates in meltwater that has interacted with rock and sediment. Hence, elevated concentrations of 222 Rn 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 222 Rn 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 222 Rn mass balance model, we estimate that, on average, greater than 90% of the river 222 Rn was sourced from distributed system meltwater. The distributed system 222 Rn 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 222 Rn, 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. Published by Elsevier B.V.

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“…It is noteworthy that others have also reported significant Ne depletion in glacial meltwater. Niu et al [ 38 ] reported on gas in glacial meltwater in Greenland, and of the 13 samples studied, nine were classified as having relative depletions of Ne with respect to Ar, Kr, and/or Xe. A similar study [ 39 ] at the Athabasca Glacier also had five out of eight samples with deletion of Ne with respect to one of the heavier noble gases.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…Fig 9 shows the pattern of the noble gases in the spring water compared to air-saturated values for the brine plotted in the format used by Niu et al [ 38 , 39 ]. The water from Little Black Pond has roughly the same noble gas pattern as the nine Greenland samples of Niu et al [ 38 ] which are the “relative Ne depletion” samples. This is especially the case for KL-T2 (Fig 1C in Niu et al [ 38 ]) and similar to the pattern of sample 03 from the Athabasca Glacier (Fig 3B in Niu et al [ 39 ]).…”

Section: Discussionmentioning

confidence: 99%

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Water sources and composition of dissolved gases and bubbles in a saline high Arctic spring

et al. 2023

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We investigate the water sources for a perennial spring, “Little Black Pond,” located at Expedition Fiord, Axel Heiberg Island in the Canadian High Arctic based on dissolved gases. We measured the dissolved O2 in the likely sources Phantom Lake and Astro Lake and the composition of noble gases (3He/4He, 4He, Ne,36Ar, 40Ar, Kr, Xe), N2, O2, CO2, H2S, CH4, and tritium dissolved in the outflow water and bubbles emanating from the spring. The spring is associated with gypsum-anhydrite piercement structures and occurs in a region of thick, continuous permafrost (400–600 m). The water columns in Phantom and Astro lakes are uniform and saturated with O2. The high salinity of the water emanating from the spring, about twice sea water, affects the gas solubility. Oxygen in the water and bubbles is below the detection limit. The N2/Ar ratio in the bubbles and the salty water is 89.9 and 40, respectively, and the relative ratios of the noble gases, with the exception of Neon, are consistent with air dissolved in lake water mixed with air trapped in glacier bubbles as the source of the gases. The Ne/Ar ratio is ~62% of the air value. Our results indicate that about half (0.47±0.1) of the spring water derives from the lakes and the other half from subglacial melt. The tritium and helium results indicate that the groundwater residence time is over 70 years and could be thousands of years.

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Noble gas signatures in Greenland: Tracing glacial meltwater sources

Cited by 9 publications

References 48 publications

Global Isotope Hydrogeology―Review

Global Isotope Hydrogeology―Review

Utility of 222Rn as a passive tracer of subglacial distributed system drainage

Water sources and composition of dissolved gases and bubbles in a saline high Arctic spring

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