Grain size distributions of the Bossons glacier (France)
| Cobertura |
MEDIAN LATITUDE: 45.883626 * MEDIAN LONGITUDE: 6.858058 * SOUTH-BOUND LATITUDE: 45.880000 * WEST-BOUND LONGITUDE: 6.849050 * NORTH-BOUND LATITUDE: 45.899417 * EAST-BOUND LONGITUDE: 6.860000 * DATE/TIME START: 2009-07-02T00:00:00 * DATE/TIME END: 2011-08-08T10:50:00 |
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| Data(s) |
16/09/2013
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| Resumo |
The study presented in this PhD memory aim at better define and quantify the present timeerosion processes in glacial and proglacial domain. The Glacier des Bossons, situated in theMont-Blanc massif (Haute-Savoie, France), is a good example of a natural and nonanthropizedsystem which allows us to study this topic. This glacier lies on two mainlithologies (the Mont-Blanc granite and the metamorphic bedrock) and this peculiarity is usedto determine the origin of the glacial sediments. The sediments were sampled at the glaciersurface and at the glacier sole and also in the subglacial streams in order to understand themechanisms of mechanical erosion and particle transportation in glacial domain. The study ofthe granulometric distribution and the origin of the sediments were performed by a lithologicanalysis at macro-scale (naked-eye) and a geochemical analysis at micro-scale (U-Pb datingof zircons). These analyses allowed specifying the characteristics of glacial erosion andtransport. (1) the supraglacial sediments derived from the erosion of the rocky valley sides aremainly coarse and the glacial transport does not mix these clasts with those derived from thesub-glacial erosion, except in the lower tongue; (2) the sub-glacial erosion rates areinhomogeneous, erosion under the temperate glacier (0.4-0.8 mm/yr) is at least sixteen timesmore efficient than the erosion under the cold glacier (0.025-0.05 mm/yr); (3) the sub-glacialsediments contain a silty and sandy fraction, resulting from processes of abrasion andcrushing, which is evacuated by sub-glacial streams. The high-resolution temporal acquisitionof hydro-sedimentary data during the 2010 melt season, between the May 5th and theSeptember 17th, allowed defining the seasonal behavior of the hydrologic and sedimentaryfluxes. The sediment exportation occurs mainly during the melt season therefore, quantify thesediment fluxes in the Bossons stream and measure regularly the topographic evolution of thefluvio-glacial system allows to perform a sedimentary balance of the erosion of glacial andnon-glacial domains. During the year 2010, about 3000 tons of sediments were eroded with430 tons settled on the fluvio-glacial system. By analyzing the evolution of suspendedparticulate matter concentrations in the Bossons stream upstream and downstream the fluvioglacialsystem, the part of glacial erosion and non-glacial denudation in the sedimentarybalance could be proportioned. The erosion during the stormy events of the uncoveredmoraines, confining the fluvio-glacial system of the Bossons stream, furnishes at least 59% ofthe sediments exported by the Bossons stream and glacial erosion (41% of the flux) istherefore less efficient comparatively. The long-term evolution of the glacial systems inperiod of global warming would show a sustained erosion of proglacial environments(mountain sides and moraines) recently exposed and therefore an increasing of the detritalfluxes. The Glacier des Bossons protects the summit of the Mont-Blanc, the differentialerosion between zones under the ice and non-glacial could lead to an increase of thedifference of altitude between valleys and summits. |
| Formato |
application/zip, 5 datasets |
| Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.835991 doi:10.1594/PANGAEA.835991 |
| Idioma(s) |
en |
| Publicador |
PANGAEA |
| Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
| Fonte |
Supplement to: Godon, Cécile (2013): L'érosion dans les environnements glaciaires : exemple du Glacier des Bossons (Massif du Mont-Blanc, Haute-Savoie, France) = Erosion in glacial environments : example of the Glacier des Bossons (Massif du Mont-Blanc, Haute-Savoie, France). Université de Grenoble, v1, 212 pp, http://tel.archives-ouvertes.fr/tel-00909603 |
| Palavras-Chave | #<4 µm; 0.013-0.010 µm; 0.016-0.126 µm; 0.020-0.157 µm; 0.025-0.02 µm; 0.026-0.020 µm; 0.0315-0.025 µm; 0.032-0.026 µm; 0.04-0.0315 µm; 0.041-0.032 µm; 0.05-0.04 µm; 0.052-0.041 µm; 0.063-0.05 µm; 0.065-0.052 µm; 0.08-0.063 µm; 0.083-0.065 µm; 0.1-0.08 µm; 0.105-0.083 µm; 0.125-0.1 µm; 0.132-0.105 µm; 0.16-0.125 µm; 0.167-0.132 µm; 0.2-0.16 µm; 0.211-0.167 µm; 0.25-0.2 µm; 0.267-0.211 µm; 0.315-0.25 µm; 0.338-0.267 µm; 0.400-0.315 µm; 0.428-0.338 µm; 0.5-0.4 µm; 0.541-0.428 µm; 0.630-0.500 µm; 0.684-0.541 µm; 0.8-0.63 µm; 0.865-0.684 µm; 1.094-0.865 µm; 1.25-1 µm; 1.25-1 mm; 1.383-1.094 µm; 1.6-1.25 µm; 1.6-1.25 mm; 1.749-1.383 µm; 1-0.5 mm; 1-0.8 µm; 1-0.8 mm; 100-80 µm; 10-5 mm; 10-8 µm; 11.436-9.044 µm; 119.596-94.574 µm; 12.5-10 µm; 1250.674-989.012 µm; 125-100 µm; 125-63 µm; 14.462-11.436 µm; 151.237-119.596 µm; 1581.565-1250.674 µm; 160-125 µm; 160-80 mm; 16-12.5 µm; 18.288-14.462 µm; 191.25-151.237 µm; 2.0-1.6 µm; 2.0-1.6 mm; 2.211-1.749 µm; 2.5-2 µm; 2.797-2.211 µm; 2000-1581.656 µm; 200-160 µm; 20-10 mm; 20-16 µm; 2-1 mm; 23.127-18.288 µm; 241.849-191.25 µm; 250-125 µm; 250-200 µm; 25-20 µm; 29.245-23.127 µm; 3.15-2.5 µm; 3.536-2.797 µm; 305.835-241.849 µm; 31.5-25 µm; 315-250 µm; 320-160 mm; 36.983-29.245 µm; 386.75-305.835 µm; 4.472-3.536 µm; 400-315 µm; 40-20 mm; 40-31.5 µm; 4-3.15 µm; 46.767-36.983 µm; 489.072-386.75 µm; 5.655-4.472 µm; 500-250 µm; 500-400 µm; 50-40 µm; 5-2 mm; 5-4 µm; 59.141-46.767 µm; 6.3-5 µm; 618.466-489.072 µm; 630-500 µm; 63-4 µm; 63-50 µm; 7.152-5.655 µm; 74.788-59.141 µm; 782.093-618.466 µm; 800-630 µm; 80-40 mm; 80-63 µm; 8-6.3 µm; 9.044-7.152 µm; 94.574-74.788 µm; 989.012-782.093 µm; Date/Time; DATE/TIME; Date/time end; Distance; Fraction; Laser micro-granulometry; Latitude; LATITUDE; Longitude; LONGITUDE; Mass; Replicate; Sample ID; Size fraction; Size fraction < 0.004 mm, clay; Size fraction 0.0025-0.002 mm; Size fraction 0.005-0.004 mm; Size fraction 0.0063-0.005 mm; Size fraction 0.008-0.0063 mm; Size fraction 0.010-0.008 mm; Size fraction 0.025-0.020 µm; Size fraction 0.0315-0.025 µm; Size fraction 0.040-0.0315 µm; Size fraction 0.050-0.040 µm; Size fraction 0.050-0.040 mm; Size fraction 0.063-0.004 mm, silt; Size fraction 0.063-0.050 µm; Size fraction 0.063-0.050 mm; Size fraction 0.080-0.063 µm; Size fraction 0.080-0.063 mm; Size fraction 0.100-0.080 µm; Size fraction 0.100-0.080 mm; Size fraction 0.125-0.063 mm, 3.0-4.0 phi, very fine sand; Size fraction 0.125-0.100 µm; Size fraction 0.125-0.100 mm; Size fraction 0.160-0.125 µm; Size fraction 0.160-0.125 mm; Size fraction 0.200-0.160 µm; Size fraction 0.200-0.160 mm; Size fraction 0.250-0.125 mm, 2.0-3.0 phi, fine sand; Size fraction 0.250-0.200 µm; Size fraction 0.250-0.200 mm; Size fraction 0.315-0.250 µm; Size fraction 0.315-0.250 mm; Size fraction 0.400-0.315 µm; Size fraction 0.400-0.315 mm; Size fraction 0.500-0.250 mm, 1.0-2.0 phi, medium sand; Size fraction 0.500-0.400 µm; Size fraction 0.500-0.400 mm; Size fraction 0.630-0.500 µm; Size fraction 0.630-0.500 mm; Size fraction 0.800-0.630 µm; Size fraction 0.800-0.630 mm; Size fraction 1.000-0.500 mm, 0.0-1.0 phi, coarse sand; Size fraction 1.000-0.800 µm; Size fraction 1.000-0.800 mm; Size fraction 1.250-1.000 µm; Size fraction 1.250-1.000 mm; Size fraction 1.600-1.250 mm; Size fraction 1.6-1.25 µm; Size fraction 10-5 mm, gravel; Size fraction 12.5-10.0 µm; Size fraction 16.0-12.5 µm; Size fraction 160-80 mm, cobbles; Size fraction 2.000-1.000 mm, (-1.0)-0.0 phi, very coarse sand; Size fraction 2.0-1.6 µm; Size fraction 2.0-1.6 mm; Size fraction 20-10 mm, fine pebbles, gravel; Size fraction 20-16 µm; Size fraction 25-20 µm; Size fraction 3.15-2.5 µm; Size fraction 31.5-25 µm; Size fraction 320-160 mm, cobbles; Size fraction 4.0-3.15 µm; Size fraction 40-20 mm, medium pebbles; Size fraction 40-31.5 µm; Size fraction 5-2 mm, granular gravel; Size fraction 80-40 mm, coarse pebbles; to outlet |
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Dataset |
