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Title: Evidence for seasonal subglacial outburst events at a polythermal-based glacier, Finsterwalderbreen, Svalbard
Authors: Wadham, Jemma
Hodgkins, Richard
Cooper, Richard
Tranter, Martyn
Issue Date: 2001
Publisher: © John Wiley & Sons, Ltd.
Citation: WADHAM, J.L. ... et al, 2001. Evidence for seasonal subglacial outburst events at a polythermal-based glacier, Finsterwalderbreen, Svalbard. Hydrological Processes, 15(12), pp. 2259-2280
Abstract: Bulk runoff and meteorological data suggest the occurrence of two meltwater outburst events at Finsterwalderbreen, Svalbard, during the 1995 and 1999 melt seasons. Increased bulk meltwater concentrations of Cl during the outbursts indicate the release of snowmelt from storage. Bulk meltwater hydrochemical data and suspended sediment concentrations suggest that this snowmelt accessed a chemical weathering environment characterized by high rock:water ratios and long rock–water contact times. This is consistent with a subglacial origin. The trigger for both the 1995 and 1999 outbursts is believed to be high rates of surface meltwater production and the oversupply of meltwater to areas of the glacier bed that were at the pressure melting point, but which were unconnected to the main subglacial drainage network. An increase in subglacial water pressure to above the overburden pressure lead to the forcing of a hydrological connection between the expanding subglacial reservoir and the ice-marginal channelized system. The purging of ice blocks from the glacier during the outbursts may indicate the breach of an ice dam during connection. Although subglacial meltwater issued continually from the glacier terminus via a subglacial upwelling during both melt seasons, field observations showed outburst meltwaters were released solely via an ice-marginal channel. It is possible that outburst events are a seasonal phenomenon at this glacier and reflect the periodic drainage of meltwaters from the same subglacial reservoir from year to year. However, the location of this reservoir is uncertain. A 100 m high bedrock ridge traverses the glacier 6Ð5 km from its terminus. The overdeepened area up-glacier from this is the most probable site for subglacial meltwater accumulation.
Description: This article is Restricted Access. It was published in the journal, Hydrological Processes [© John Wiley & Sons, Ltd.] and is available at: http://www3.interscience.wiley.com/cgi-bin/issn?DESCRIPTOR=PRINTISSN&VALUE=0885-6087
URI: https://dspace.lboro.ac.uk/2134/3327
ISSN: 0885-6087
Appears in Collections:Closed Access (Geography and Environment)

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