No abstract

In the last decade deposition on lateral moraine embankments of glacier de Tsidjiore Nouve has been re-activated on a large scale. An attempt has been made to reconstruct, from the dimensions of the embankments, average rates of debris accumulation on the moraines during the Neoglacial period. These are compared with rates of deposition over the period 1977–82, calculated from detailed changes in moraine profiles (surveyed by ground- and air-based photogrammetry) and measured rates of ice-margin ablation. At present total output of sediment, by marginal deposition and transport by melt-water streams, from glacier de Tsidjiore Nouve is in the order of 6400–9500m3/a; this suggests the possibility of a high average erosion rate within the glacier catchment of 1.55–2.29 mm/a.

Between 16 and 19 June 1981 a large water pocket of volume 183 000 m3burst from glacier de Tsidjiore Nouve. From hourly stream discharge and suspended sediment concentration observations a suspended sediment output of 1 674 × 103kg was calculated. The transport of bed-load was estimated at 3 840 × 103kg, hence a total quantity of around 5 500 × 103kg of sediment were removed from the catchment, including the pro-glacial field, in the four days of the outburst.

(D epartmel1l of Geog raph y, niversit y of South ampton, South a mpton S09 5AH , England ) and D. M. STIRLIN G (Department of Civil En gin ee ring, City University, Northampton Square, London EC I V OHB, Engl a nd ) AB ST R ACT . In the last d ecad e d eposition on la te ral m o ra ine emba nkm e nts o f g lacier d e T sidjiore N o u ve has bee n re-ac ti va ted o n a la rge sca le. An a tte mpt has bee n mad e to reconstruct, from th e dimensions orlhe emba nkme nts, average rates of d ebris acc umul a ti on o n the m ora in cs during th e Neoglacia l peri od . These a re compa red with ra tes o f d eposition over th e peri od 1977-82, calc ul a ted from d etailed cha nges in mo ra ine profil es (surveyed b y ground-a nd air-based photogrammetry) and measured ra tes o f ice-m a rg in ablation. At prese nt total output o f sediment, by ma rg inal d e position a nd tra nsport by melt-wate r streams, fro m glacier de T sidj io re Nouve is in the order o f 6 400-9 500 m 3 /a; this su ggests th e possibility o f a high ave rage erosion ra te within th e glacier ca tc hme nt of 1,55-2.29 mm /a . R ESU l\.U~ •. Taux de depat sur les lerrasses morainiques lalira/es , glacier de T sidjiore .Nou ve, l'alais. Suisse. Pe ndant la dern ierc dece nni c, le re mblaiemcnt sur les le rrasscs morainiqu es late rales du glacier de T sidji o re NOll ve a recommen ce sur une gra nde ec hclle. U ne tentati ve de reco nstitutio n des ta ux moyens d 'accumul a ti on de d ebris sur les te rrasses mo ra iniqu es penda nt la pe ri od e ncoglac ia re a ete faite. ees ta ux sont compa res avec ccux de la pc ri od e 19 78-82, ca leules it pa rtir d es cha nge mcnts d e ta illcs d es profils de la mora ine (to pogra phi c pa r pho togra mmclri r terres tre e t ac ri enne) ainsi qu e d e I'a bl a ti o n mes ur"e sur les bo rd s du glac ier. Ac tu clle m ent I'a pport to ta l d e

Between 16 and 19 June 1981 a large water pocket of volume 183 000 m3 burst from glacier de Tsidjiore Nouve. From hourly stream discharge and suspended sediment concentration observations a suspended sediment output of 1 674 × 103 kg was calculated. The transport of bed-load was estimated at 3 840 × 103 kg, hence a total quantity of around 5 500 × 103 kg of sediment were removed from the catchment, including the pro-glacial field, in the four days of the outburst.