The Bossons glacier protects Europe's summit from erosion

Godon, Cécile; Mugnier, Jean‐Louis; Fallourd, Renaud; Paquette, Jean‐Louis; Pohl, Alexandre; Buoncristiani, Jean‐François

doi:10.1016/j.epsl.2013.05.018

Cited by 17 publications

(53 citation statements)

References 60 publications

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“…composed of Ordovician orthogneisses. The ice thickness of the Bossons glacier has a mean value of 60 m and a maximum of ∼160 m (Huss and Farinotti, 2012;Godon et al, 2013). The Bossons glacier is inferred to be polythermal.…”

Section: Geological Settingmentioning

confidence: 98%

“…Two other streams, Creuse (outlet at 2,300 m) and Bossons (outlet at 1,450 m) flow into the Arve River. Although the details of the subglacial meltwater network are unknown, Godon et al (2013) suggested that the highest outlet (Creuse) drains mostly from the Tacul glacier, while the lowest outlet (Bossons) collects subglacial meltwater from a relatively small catchment area of less than 0.5 km 2 . The bedrock in the catchment of the Bosson glacier consists of calc-alkaline granites (ca.…”

Section: Geological Settingmentioning

confidence: 99%

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

et al. 2017

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Cold climate carbonates can be used as paleoclimatic proxies. The mineralogy and isotopic composition of subglacially precipitated carbonate crusts (SPCCs) provide insights into the subglacial conditions and processes occurring at the meltwaterbasement rock interface of glaciers. This study documents such crusts discovered on the lee side of a gneissic roche moutonnée at the terminus of the Bossons glacier in the Mont Blanc Massif area (France). The geological context and mineralogical investigations suggest that the Ca used for the precipitation of large crystals of radial fibrous sparite observed in these crusts originated from subglacial chemical weathering of Ca-bearing minerals of the local bedrock (plagioclase and amphibole). Measurements of the carbon and oxygen isotope compositions in the crusts indicate precipitation at, or near to, equilibrium with the basal meltwater under open system conditions during refreezing processes. The homogeneous and low carbonate δ 13 C values (ca. −11.3‰) imply a large contribution of soil organic carbon to the Bossons subglacial meltwater carbon reservoir at the time of deposition. In addition, organic remains trapped within the SPCCs give an age of deposition around 6,500 years cal BP suggesting that the Mid-Holocene climatic and pedological optima are archived in the Bossons glacier carbonate crusts.

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Section: Geological Settingmentioning

confidence: 98%

Section: Geological Settingmentioning

confidence: 99%

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

et al. 2017

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“…The altitude of the equilibrium line between its accumulation and ablation areas is estimated to be 2780˙100 m asl (Godon et al, 2013). This 12 km long ice fall starts at the top of Mont Blanc (4810 m above sea level (asl)) and reaches down to 1450 m asl.…”

Section: The Bossons Glacier Catchment: a Field Laboratory For Presenmentioning

confidence: 99%

“…In addition, the recent thorough review by Carrivick and Heckmann (2017) asserts the need to quantify landscape evolution in proglacial areas as well as their geomorphological characteristics. Initiated by Godon (2013), our final aim is to set up a perennial field laboratory for studying present-day erosion processes. Initiated by Godon (2013), our final aim is to set up a perennial field laboratory for studying present-day erosion processes.…”

Section: Introductionmentioning

confidence: 99%

Proglacial sediment dynamics from daily to seasonal scales in a glaciated Alpine catchment (Bossons glacier, Mont Blanc massif, France)

Guillon

Mugnier

Buoncristiani

2018

Earth Surf Processes Landf

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The sediment yields of Alpine catchments are commonly determined from streamload measurements made some distance downstream from glaciers. However, this approach indiscriminately integrates erosion processes occurring in both the glacial and proglacial areas. A specific method is required to ascertain the respective inputs from (i) subglacial and supraglacial sediments, (ii) proglacial hillslopes and (iii) proglacial alluvial areas or sandurs. This issue is addressed here by combining high‐resolution monitoring (2 min) of suspended sediment concentrations at different locations within a catchment with discharge gauging and precipitation data. This methodological framework is applied to two proglacial streams draining the Bossons glacier (Mont Blanc massif, France): the Bossons and Crosette streams. For the Bossons stream, discharge and suspended load data were acquired from June to October 2013 at 1.15 and 1.5 km from the glacial terminus, respectively upstream and downstream from a small valley sandur. These hydro‐sedimentary data are compared with the Crosette stream dataset acquired at the outlet of the Bossons glacier subglacial drainage system. A fourfold analysis focusing on seasonal changes in streamload and discharge, multilinear regression modelling, evaluation of the sandur flux balance and probabilistic uncertainty assessment is used to determine the catchment sediment budget and to explain the proglacial sediment dynamics. The seasonal fluctuation of the sediment signal observed is related to the gradual closing of the subglacial drainage network and to the role of the proglacial area in the sediment cascade: the proglacial hillslopes appear to be disconnected from the main channel and the valley sandur acts as a hydrodynamic sediment buffer both daily and seasonally. Our findings show that an understanding of proglacial sediment dynamics can help in evaluating paraglacial adjustment and subglacial erosion processes. Copyright © 2017 John Wiley & Sons, Ltd.

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“…Yet, many existing reservoirs in the tropical Andes, including the Cañon del Pato hydropower dam on the Santa River, are already operated as multi-purpose reservoirs. Furthermore, hydropower installations may be faced with increased sediment influx as glacier retreat will increasingly expose bare slopes and lead to increased erosion and discharge of suspended sediments (Finer and Jenkins, 2012;Godon et al, 2013). They also threaten ecological connectivity between high and lowland river species along river systems and pose barriers for migrating species, in particular on the eastern slopes of the Andes, where over 150 new dams were in a planning phase in different Andean countries in 2011 (Finer and Jenkins, 2012).…”

Section: Water Usementioning

confidence: 99%

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

Vuille

Carey

Huggel

et al. 2018

Earth-Science Reviews

230

210

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Glaciers in the tropical Andes have been retreating for the past several decades, leading to a temporary increase in dry season water supply downstream. Projected future glacier shrinkage, however, will lead to a long-term reduction in dry season river discharge from glacierized catchments. This glacier retreat is closely related to the observed increase in high-elevation, surface air temperature in the region. Future projections using a simple freezing level height-equilibrium-line altitude scaling approach suggest that glaciers in the inner tropics, such as Antizana in Ecuador, may be most vulnerable to future warming while glaciers in the more arid outer tropics, such as Zongo in Bolivia, may persist, albeit in a smaller size, throughout the 21st century regardless of emission scenario. Nonetheless many uncertainties persist, most notably problems with accurate snowfall measurements in the glacier accumulation zone, uncertainties in establishing accurate thickness measurements on glaciers, unknown future changes associated with local-scale circulation and cloud cover affecting glacier energy balance, the role of aerosols and in particular black carbon deposition on Andean glaciers, and the role of groundwater and aquifers interacting with glacier meltwater.The reduction in water supply for export-oriented agriculture, mining, hydropower production and human consumption are the most commonly discussed concerns associated with glacier retreat, but many other aspects including glacial hazards, tourism and recreation, and ecosystem integrity are also affected by glacier retreat. Social and political problems surrounding water allocation for subsistence farming have led to conflicts due to lack of adequate water governance. Local water management practices in many regions reflect cultural belief systems, perceptions and spiritual values and glacier retreat in some places is seen as a threat to these local livelihoods.Comprehensive adaptation strategies, if they are to be successful, therefore need to consider science, policy, culture and practice, and involve local populations. Planning needs to be based not only on future scenarios derived from physically-based numerical models, but must also consider societal needs, economic agendas, political conflicts, socioeconomic inequality and cultural values. This review elaborates on the need for adaptation as well as the challenges and constraints many adaptation projects are faced with, and lays out future directions where opportunities exist to develop successful, culturally acceptable and sustainable adaptation strategies.

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The Bossons glacier protects Europe's summit from erosion

Cited by 17 publications

References 60 publications

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

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

Proglacial sediment dynamics from daily to seasonal scales in a glaciated Alpine catchment (Bossons glacier, Mont Blanc massif, France)

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

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