TY - JOUR
T1 - Ice-marginal sediment delivery to the surface of a high-arctic glacier: Austre Broggerbreen, Svalbard
AU - Porter, Philip R.
AU - Vatne, Geir
AU - Ng, Felix
AU - Irvine-Fynn, Tristram D. L.
N1 - The definitive version is found at: http://onlinelibrary.wiley.com/ Copyright Wiley-Blackwell
PY - 2010
Y1 - 2010
N2 - Enhanced delivery of water-saturated, ice-marginal sediments to the glacier surface is a response to glacier thinning that has the potential to increase both levels of sediment transfer through the glacier hydrological system and total basin sediment yields. Preliminary observations made during summer 2007 at Austre Br circle divide ggerbreen, Svalbard, confirm that ice-marginal debris flows in the upper reaches of the glacier are actively delivering sediments to the glacier surface, which may then be flushed into the glacier's hydrological system. During a four-day observation period, several stochastic pulses in water turbidity were observed at a single portal where solely supra- and englacial drainage emerge at the glacier margin. The erratic suspended sediment fluxes were hypothesized to originate from ice-marginal sources. Quantitative analysis of continuous turbidity and discharge data confirm that discharge is not driving these turbidity pulses and, combined with observational data, that the most likely origin is the delivery of water-saturated sediments to the glacier surface from ice-marginal, debris flows with subsequent transfer to the portal via the glacial drainage system. These observations illustrate the potential importance of the paraglacial component to the overall sediment cascade of deglaciating basins and highlight the need for careful interpretation of turbidity records, where stochastic pulses in turbidity may be attributed to sources and processes other than ice-marginal sediment inputs.
AB - Enhanced delivery of water-saturated, ice-marginal sediments to the glacier surface is a response to glacier thinning that has the potential to increase both levels of sediment transfer through the glacier hydrological system and total basin sediment yields. Preliminary observations made during summer 2007 at Austre Br circle divide ggerbreen, Svalbard, confirm that ice-marginal debris flows in the upper reaches of the glacier are actively delivering sediments to the glacier surface, which may then be flushed into the glacier's hydrological system. During a four-day observation period, several stochastic pulses in water turbidity were observed at a single portal where solely supra- and englacial drainage emerge at the glacier margin. The erratic suspended sediment fluxes were hypothesized to originate from ice-marginal sources. Quantitative analysis of continuous turbidity and discharge data confirm that discharge is not driving these turbidity pulses and, combined with observational data, that the most likely origin is the delivery of water-saturated sediments to the glacier surface from ice-marginal, debris flows with subsequent transfer to the portal via the glacial drainage system. These observations illustrate the potential importance of the paraglacial component to the overall sediment cascade of deglaciating basins and highlight the need for careful interpretation of turbidity records, where stochastic pulses in turbidity may be attributed to sources and processes other than ice-marginal sediment inputs.
KW - ice-marginal
KW - paraglacial
KW - suspended sediment
UR - http://www.scopus.com/inward/record.url?scp=78650042676&partnerID=8YFLogxK
U2 - 10.1111/j.1468-0459.2010.00406.x
DO - 10.1111/j.1468-0459.2010.00406.x
M3 - Article
SN - 0435-3676
VL - 92A
SP - 437
EP - 449
JO - Geografiska Annaler: Series A, Physical Geography
JF - Geografiska Annaler: Series A, Physical Geography
IS - 4
ER -