Chemical weathering across the western foreland of the Greenland Ice Sheet

Deuerling, Kelly; Martin, Jonathan B.; Martin, E. E.; Abermann, Jakob; Myreng, Sille M.; Petersen, Dorthe; Rennermalm, Å. K.

doi:10.1016/j.gca.2018.11.025

Cited by 19 publications

(27 citation statements)

References 59 publications

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“…Strontium isotope data vs. Ca/Sr molar ratio for the water samples of this study compared with the range of strontium isotopes values for the till (this study) and for the gypsum found as fracture fillings in the underlying deep bedrock (Henkemans 2016). The figure also shows the data from Deuerling et al (2019) for the Watson River and the rivers discharging the Russell and Leverett Glaciers (Hindshaw et al 2014;Linhoff 2016; at distances ranging from 2 km to about 30 km southwest of our study site.…”

Section: Sodium Potassium and Silicamentioning

confidence: 98%

“…Here we present a geochemical data set to study the weathering processes in a historical moraine in a landterminating region of the Greenland Ice Sheet (GrIS). The study site, near Kangerlussuaq, was selected due to logistic considerations and because previous geochemical studies are available on a nearby sandur (Deuerling et al 2018) as well as for the ice sheet and some river systems and lakes of the area (Scholz and Baumann 1997;Anderson et al 2001;Wimpenny et al 2010Wimpenny et al , 2011Ryu and Jacobson 2012;Graly et al 2014;Hawkings et al 2014Hawkings et al , 2015Hindshaw et al 2014;Aciego, Stevenson, and Arendt 2015;Graly, Humphrey, and Harper 2016;Lindborg et al 2016;Rydberg et al 2016;Stevenson et al 2017;Henkemans et al 2018;Deuerling et al 2019). In the period between 2008 and 2013, a collaborative field and modeling study, the Greenland Analogue Project (GAP), was conducted in the Kangerlussuaq area (Claesson Liljedahl et al 2016) by the national nuclear waste management organizations in Sweden (Swedish Nuclear Fuel and Waste Management Company), Finland (Posiva), and Canada (Nuclear Waste Management Organization).…”

Section: Introductionmentioning

confidence: 99%

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Chemical weathering in a moraine at the ice sheet margin at Kangerlussuaq, western Greenland

Auqué

Puigdomènech

Tullborg³

et al. 2019

Arctic, Antarctic, and Alpine Research

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Weathering caused by interaction between glacial sediments and water in exposed moraines needs to be studied to evaluate their possible effects on the global carbon cycle. In this study, moraine ponds, moraine porewaters, and till samples were collected at a moraine adjacent to the Greenland Ice Sheet at Kangerlussuaq. Scanning electron microscopy (SEM) studies of the till show limited evidence of silicate chemical weathering, but the moraine waters have substantial solute concentrations. δ 34 S SO4 and δ 18 O SO4 data indicate that the origin of dissolved sulfate is the oxidation of sulfides, in agreement with the SEM observations. The dissolved HCO 3 − /SO 4 2− molar ratios indicate an uneven balance between sulfuric and carbonic acid weathering; C-isotope data indicate that some of the CO 2 originates from organic carbon mineralization. Ion-ion plots provide evidence of carbonate weathering and of the formation of secondary gypsum and calcite through evaporation and (or) cryoconcentration. The 87 Sr/ 86 Sr ratios in the waters correlate with the corresponding till samples, supporting the local origin of the dissolved strontium, which is higher in the waters than in the till due to the selective weathering of biotite. The data evidence a large degree of chemical weathering in moraines promoted by large rock-water ratios and by the hydraulic isolation created by the frozen till. The high P CO2 in the studied moraine waters indicates that they may represent a previously underestimated CO 2 source.

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Section: Sodium Potassium and Silicamentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Chemical weathering in a moraine at the ice sheet margin at Kangerlussuaq, western Greenland

Auqué

Puigdomènech

Tullborg³

et al. 2019

Arctic, Antarctic, and Alpine Research

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“…Maher et al, 2004; Till, Guyodo, Lagroix, Morin, & Ona‐Nguema, 2015). Chemical weathering onshore Greenland is typically limited to reworked moraine and glacial sediments along pro‐glacial and non‐glacial streams, and mostly selective to carbonate minerals (Deuerling et al, 2019). Therefore, the typical fresh exposures in Greenland where our samples were collected suggest that goethite was not formed as a result of chemical alteration during weathering.…”

Section: Discussionmentioning

confidence: 99%

The thermal maturity of sedimentary basins as revealed by magnetic mineralogy

Abdelmalak

Polteau

2020

Basin Research

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The thermal evolution of sedimentary basins is usually constrained by maturity data, which is interpreted from Rock-Eval pyrolysis and vitrinite reflectance analytical results on field or boreholes samples. However, some thermal evolution models may be inaccurate due to the use of elevated maturities measured in samples collected within an undetected metamorphic contact aureole surrounding a magmatic intrusion.

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“…Global Biogeochemical Cycles of sulfuric acid (Deuerling et al, 2019) or colder temperatures that would reduce dissolution rates and short residence times of glacial streams.…”

Section: 1029/2020gb006661mentioning

confidence: 99%

“…Nonetheless, increased weathering extent is shown by decreasing offsets between bedload and dissolved 87 Sr/ 86 Sr ratios with increased exposure age and precipitation across a transect of deglaciated watersheds in southwestern Greenland that extends from the ice to the coast (Scribner et al, 2015). The increased weathering corresponds to a switch from mostly carbonic acid weathering of carbonate minerals near the ice sheet to mostly sulfuric acid weathering of silicate minerals near the coast, which also modifies the major solute compositions of the stream water (Deuerling et al, 2019). These weathering reactions differ from sub‐glacial weathering reactions under the GrIS where products are derived from hydrolysis and carbonic acid weathering of silicate minerals (Graly et al, 2014; Hatton et al, 2019; Urra et al, 2019), even though both regions are underlain by the same bedrock lithology.…”

Section: Introductionmentioning

confidence: 99%

Comparisons of Nutrients Exported From Greenlandic Glacial and Deglaciated Watersheds

Martin

Pain

Martin

et al. 2020

Global Biogeochemical Cycles

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Recent work demonstrates extensive nutrient exports from outlet glaciers of the Greenland Ice Sheet. In comparison, nutrient exports are poorly defined for deglaciated watersheds that were exposed during ice retreat and retain reactive comminuted glacial sediments. Nutrient exports from deglaciated watersheds may differ from glacial watersheds due to their longer exposure times, more mature chemical weathering, and ecosystem succession. To evaluate nutrient exports from glacial and deglaciated watersheds, we compare discharge and dissolved (<0.45 μm filtered) nutrient concentrations in two glacial and six non-glacial streams in southwestern and southern Greenland. Glacial streams have orders of magnitude greater instantaneous discharge than non-glacial streams but their specific discharges are more similar, differing by up to a factor of 10. Compared with non-glacial streams, filtered water of glacial streams have on average (1) higher inorganic nitrogen (DIN) and PO 4 concentrations, lower Si concentrations, and Fe concentrations that are not statistically different; (2) higher DIN and PO 4 but lower Si specific yields; and (3) lower DIN/PO 4 , Si/DIN, and Fe/PO 4 ratios, but indistinguishable Fe/DIN. Maximum specific yields occur in early melt season prior to maximum solar radiation for non-glacial streams, and in mid-melt season as solar radiation wanes for proglacial streams. Impacts to coastal ecosystems from nutrient exports depend on suspended sediment loads and processing in the estuaries, but landscape exposure during glacial terminations should decrease DIN and dissolved PO 4 and increase dissolved Si exports, while increased meltwater runoff associated with future warming should increase DIN and dissolved PO 4 and decrease dissolved Si exports. Plain Language Summary Large ice sheets have advanced and retreated across about 15% of Earth's land surface over the past few million years. Watersheds exposed during ice retreat develop ecosystems and altered chemical reactions of fine-grained glacial sediment that change stream water chemical compositions. Although individual glacial streams tend to be larger than non-glacial streams, their discharge volumes per land area are similar within about a factor of 10. Comparisons of chemical compositions of glacial streams draining the Greenland Ice Sheet and nearby non-glacial streams document different amounts of nutrients discharging from the landscapes. Once filtered to remove particles, stream waters draining the ice sheet contain more nitrogen and phosphorous, less silica, and about equal amounts of iron compared to non-glacial streams. These differences in nutrient exports affect the abundance of nutrients in coastal ecosystems. Differences in timing of the maximum export relative to daily light levels may also affect photosynthesis. The response of coastal ecosystems to past continental ice sheet advance and retreat, and to increases in meltwater due to Arctic warming, may be affected by relative nutrient contributions from glacial and non-glacial streams.

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Chemical weathering across the western foreland of the Greenland Ice Sheet

Cited by 19 publications

References 59 publications

Chemical weathering in a moraine at the ice sheet margin at Kangerlussuaq, western Greenland

Chemical weathering in a moraine at the ice sheet margin at Kangerlussuaq, western Greenland

The thermal maturity of sedimentary basins as revealed by magnetic mineralogy

Comparisons of Nutrients Exported From Greenlandic Glacial and Deglaciated Watersheds

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