Geochemical Processes Leading to the Precipitation of Subglacial Carbonate Crusts at Bossons Glacier, Mont Blanc Massif (French Alps)

Thomazo, Christophe; Buoncristiani, Jean‐François; Vennin, Emmanuelle; Pellenard, Pierre; Cocquerez, Théophile; Mugnier, Jean‐Louis; Gérard, Emmanuelle

doi:10.3389/feart.2017.00070

Cited by 12 publications

(13 citation statements)

References 52 publications

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“…moraines), subglacial carbonates may be eroded in a matter of decades (Ford et al, 1970), suggesting their exposure can be recent. They have been reported from deglaciated areas of northern North America (Ford et al, 1970;Hallet, 1976;Refsnider et al, 2012), northern Europe and the European Alps (Lemmens et al, 1982;Souchez and Lemmens, 1985;Sharp et al, 1990;Lacelle, 2007;Gabrovec et al, 2014;Colucci, 2016;Thomazo et al, 2017), Tibet (Risheng et al, 2003), New Guinea (Peterson and Moresby, 1979), and Antarctica (Aharon, 1988;Frisia et al, 2017). The uranium-thorium (U-Th) method remains the main dating technique for these Figure 1.…”

Section: Introductionmentioning

confidence: 97%

Subglacial carbonate deposits as a potential proxy for a glacier's former presence

et al. 2021

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Abstract. The retreat of ice shelves and glaciers over the last century provides unequivocal evidence of recent global warming. Glacierets (miniature glaciers) and ice patches are important components of the cryosphere that highlight the global retreat of glaciers, but knowledge of their behaviour prior to the Little Ice Age is lacking. Here, we report the uranium–thorium age of subglacial carbonate deposits from a recently exposed surface previously occupied by the disappearing Triglav Glacier (southeastern European Alps) that may elucidate the glacier's presence throughout the entire Holocene. The ages suggest the deposits' possible preservation since the Last Glacial Maximum and Younger Dryas. These thin deposits, formed by regelation, are easily eroded if exposed during previous Holocene climatic optima. The age data indicate the glacier's present unprecedented level of retreat since the Last Glacial Maximum and the potential of subglacial carbonates as additional proxies to highlight the extraordinary nature of the current global climatic changes.

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Section: Introductionmentioning

confidence: 97%

Subglacial carbonate deposits as a potential proxy for a glacier's former presence

et al. 2021

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“…Water sources originating from permafrost-underlined vegetated terrains are usually characterized by higher concentrations of DOC than the nearby permafrost-free areas due to extended exposure to the organic-reach suprapermafrost layer (Carey, 2003;Ma et al, 2019;MacLean et al, 1999). DOC can, therefore, be seen as a tracer for permafrost-related water sources (e.g., Petrone et al, 2006;Toohey et al, 2016;Yoshikawa et al, 2007). We measured DOC concentrations using an Apollo 9000 combustion analyzer.…”

Section: Analysis Of Dissolved Organic Carbonmentioning

confidence: 99%

“…An increase in suprapermafrost layer thickness in response to the changing climate should lead to the increased storage capacity of an aquifer, which in turn can also lead to increased winter discharge (Ge et al, 2011;Toohey et al, 2016). In addition, the formation of taliks activates the groundwater system which is otherwise shut down during the winter season (Lamontagne-Hallé et al, 2018;Pomortscev et al, 2010).…”

Section: Findings On Winter Hydrological Processes and Implications Fmentioning

confidence: 99%

“…The hypotheses proposed to explain this positive trend mainly fall into two categories: those based on a change in water storage capacity of aquifers and those based on a change in water inputs to aquifers from different hydrological sources (Liljedahl et al, 2016). Increases in aquifer storage capacity result from delays in soil freezeup (e.g., Yang et al, 2002), increases in suprapermafrost layer thickness (e.g., Ge et al, 2011;Toohey et al, 2016), or both. These phenomena may lead to an increased amount of water accumulated in the aquifer during summer that can be released during the freezing season.…”

Section: Introductionmentioning

confidence: 99%

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Proglacial icings as records of winter hydrological processes

Chesnokova

Baraër²,

Bouchard³

2020

The Cryosphere

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Abstract. The ongoing warming of cold regions is affecting hydrological processes, causing deep changes, such as a ubiquitous increase in river winter discharges. The drivers of this increase are not yet fully identified mainly due to the lack of observations and field measurements in cold and remote environments. In order to provide new insights into the sources generating winter runoff, the present study explores the possibility of extracting information from icings that form over the winter and are often still present early in the summer. Primary sources detection was performed using time-lapse camera images of icings found in both proglacial fields and upper alpine meadows in June 2016 in two subarctic glacierized catchments in the upper part of the Duke watershed in the St. Elias Mountains, Yukon. As images alone are not sufficient to entirely cover a large and hydrologically complex area, we explore the possibility of compensating for that limit by using four supplementary methods based on natural tracers: (a) stable water isotopes, (b) water ionic content, (c) dissolved organic carbon, and (d) cryogenic precipitates. The interpretation of the combined results shows a complex hydrological system where multiple sources contribute to icing growth over the studied winter. Glaciers of all sizes, directly or through the aquifer, represent the major parent water source for icing formation in the studied proglacial areas. Groundwater-fed hillslope tributaries, possibly connected to suprapermafrost layers, make up the other detectable sources in icing remnants. If similar results are confirmed in other cold regions, they would together support a multi-causal hypothesis for a general increase in winter discharge in glacierized catchments. More generally, this study shows the potential of using icing formations as a new, barely explored source of information on cold region winter hydrological processes that can contribute to overcoming the paucity of observations in these regions.

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“…The most common minerals found at the surface of the icings in the melt season are carbonates (CaCO3) and gypsum (CaSO4) (Lacelle et al, 2009). In glacierized catchments, those cryogenic minerals represent a unique archive of the hydrologic conditions that prevailed at their formation (Thomazo et al, 2017). We collected solid state samples where clear association between the precipitate and the icing was possible.…”

Section: Sample Collectionmentioning

confidence: 99%

Proglacial icings as records of winter hydrological processes

Chesnokova¹,

Baraër²,

Bouchard³

2020

Preprint

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Abstract. The ongoing warming of cold regions is affecting hydrological processes, causing deep changes such as a ubiquitous increase in river winter discharges. The drivers of this increase are not yet fully identified, mainly due to the lack of observations and field measurements in cold and remote environments. In order to provide new insights into the sources generating winter runoff, the present study explores the possibility to extract information from icings that form over the winter and are often still present early in the summer. Primary sources detection is performed using time lapse camera (TLC) images of icings found in both proglacial fields and upper alpine meadows in June 2016 in two subarctic glacierized catchments in the upper part of the Duke watershed, St. Elias Mountains, Yukon. As TLC alone are not sufficient to entirely cover a large and hydrologically complex area, we explore the possibility to compensate that limit by four supplementary methods based on natural tracers: (a) stable water isotopes, (b) water ionic content, (c) dissolved organic carbon (DOC), and (d) cryogenic precipitates. Interpretation of the combined results shows a complex hydrological system where multiple sources contribute to icings growth over the studied winter. Glaciers of all sizes, directly or through the aquifer, represent the major parent water source for icings formation in the studied proglacial areas. Groundwater-fed hillslope tributaries, possibly connected to suprapermafrost layers, make up the other detectable sources in icing remnants. If confirmed in other cold regions, those results will suggest orienting winter flow trend studies toward a multi-causal hypothesis in glacierized catchments. More generally, this study shows the potential of using icing formations as a new, barely explored source of information on cold regions’ winter hydrological processes that can contribute to overcoming the paucity of observations in these regions.

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Geochemical Processes Leading to the Precipitation of Subglacial Carbonate Crusts at Bossons Glacier, Mont Blanc Massif (French Alps)

Cited by 12 publications

References 52 publications

Subglacial carbonate deposits as a potential proxy for a glacier's former presence

Subglacial carbonate deposits as a potential proxy for a glacier's former presence

Proglacial icings as records of winter hydrological processes

Proglacial icings as records of winter hydrological processes

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