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Sedimentological, geomorphological and dynamic context of debris-mantled glaciers, Mount Everest (Sagarmatha) region, Nepal
Quaternary Science Reviews 28 (2009) 1084
Contents lists available at ScienceDirect
Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev
Sedimentological, geomorphological and dynamic context of debris-mantled glaciers, Mount Everest (Sagarmatha) region, Nepal Michael J. Hambrey a, *, Duncan J. Quincey a, Neil F. Glasser a, John M. Reynolds b, Shaun J. Richardson a, b, Samuel Clemmens a a b
Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Ceredigion, Wales SY23 3DB, UK Reynolds Geo-Sciences Ltd., Unit 17 Mold Business Park, Mold, Flintshire CH7 1XP, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 February 2008 Received in revised form 19 July 2008 Accepted 12 August 2008
This paper presents the sediment, landform and dynamic context of four avalanche-fed valley glaciers (Khumbu, Imja, Lhotse and Chukhung) in the Mount Everest (Sagarmatha) region of Nepal. All four glaciers have a mantle of debris dominated by sandy boulder-gravel that suppresses melting to an increasing degree towards the snout, leading to a progressive reduction in the overall slope of their longitudinal profile. Prominent lateral–terminal moraine complexes, also comprising sandy bouldergravel, enclose the glaciers. These terminal moraines originally grew by accretion of multiple sedimentary facies of basal glacial and supraglacial origin, probably by folding and thrusting when the glaciers were more dynamic during the Little Ice Age. The four glaciers are in various stages of recession, and demonstrate a range of scenarios from down-wasting of the glacier tongue, through morainedammed lake development, to post-moraine-dam breaching. Khumbu Glacier is at the earliest stage of supraglacial pond formation and shows no sign yet of developing a major lake, although one is likely to develop behind its >250 m high composite terminal moraine. Imja Glacier terminates in a substantial body of water behind a partially ice-cored moraine dam (as determined from geophysical surveys), but morphologically appears unlikely to be an immediate threat. Chukhung Glacier already has a breached moraine and a connected debris fan, and therefore no longer poses a threat. Lhotse Glacier has an inclined, free-draining tongue that precludes hazardous lake development. From the data assembled, a conceptual model, applicable to other Himalayan glaciers, is proposed to explain the development of large, lateral-terminal moraine complexes and associated potentially hazardous moraine dams. – 2008 Elsevier Ltd. All rights reserved.
It is with regret that this paper was erroneously published in an earlier issue, Vol. 27, No. 25-26, pp. 2361-2389, 2008, although it is actually part of this Special Issue on Natural Hazards, Extreme Events and Mountain Topography. To view the complete paper, please refer to the above citation or use this doi link: doi:10.1016/j.quascirev.2008.08.010
DOI of original article: 10.1016/j.quascirev.2008.08.010. * Corresponding author. Tel.: þ44 (0)1970 621 860; fax: þ44 (0)1970 622 659. E-mail address: [email protected] (M.J. Hambrey). 0277-3791/$ – see front matter doi:10.1016/j.quascirev.2009.04.009
Contents lists available at ScienceDirect
Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev
Sedimentological, geomorphological and dynamic context of debris-mantled glaciers, Mount Everest (Sagarmatha) region, Nepal Michael J. Hambrey a, *, Duncan J. Quincey a, Neil F. Glasser a, John M. Reynolds b, Shaun J. Richardson a, b, Samuel Clemmens a a b
Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Ceredigion, Wales SY23 3DB, UK Reynolds Geo-Sciences Ltd., Unit 17 Mold Business Park, Mold, Flintshire CH7 1XP, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 11 February 2008 Received in revised form 19 July 2008 Accepted 12 August 2008
This paper presents the sediment, landform and dynamic context of four avalanche-fed valley glaciers (Khumbu, Imja, Lhotse and Chukhung) in the Mount Everest (Sagarmatha) region of Nepal. All four glaciers have a mantle of debris dominated by sandy boulder-gravel that suppresses melting to an increasing degree towards the snout, leading to a progressive reduction in the overall slope of their longitudinal profile. Prominent lateral–terminal moraine complexes, also comprising sandy bouldergravel, enclose the glaciers. These terminal moraines originally grew by accretion of multiple sedimentary facies of basal glacial and supraglacial origin, probably by folding and thrusting when the glaciers were more dynamic during the Little Ice Age. The four glaciers are in various stages of recession, and demonstrate a range of scenarios from down-wasting of the glacier tongue, through morainedammed lake development, to post-moraine-dam breaching. Khumbu Glacier is at the earliest stage of supraglacial pond formation and shows no sign yet of developing a major lake, although one is likely to develop behind its >250 m high composite terminal moraine. Imja Glacier terminates in a substantial body of water behind a partially ice-cored moraine dam (as determined from geophysical surveys), but morphologically appears unlikely to be an immediate threat. Chukhung Glacier already has a breached moraine and a connected debris fan, and therefore no longer poses a threat. Lhotse Glacier has an inclined, free-draining tongue that precludes hazardous lake development. From the data assembled, a conceptual model, applicable to other Himalayan glaciers, is proposed to explain the development of large, lateral-terminal moraine complexes and associated potentially hazardous moraine dams. – 2008 Elsevier Ltd. All rights reserved.
It is with regret that this paper was erroneously published in an earlier issue, Vol. 27, No. 25-26, pp. 2361-2389, 2008, although it is actually part of this Special Issue on Natural Hazards, Extreme Events and Mountain Topography. To view the complete paper, please refer to the above citation or use this doi link: doi:10.1016/j.quascirev.2008.08.010
DOI of original article: 10.1016/j.quascirev.2008.08.010. * Corresponding author. Tel.: þ44 (0)1970 621 860; fax: þ44 (0)1970 622 659. E-mail address: [email protected] (M.J. Hambrey). 0277-3791/$ – see front matter doi:10.1016/j.quascirev.2009.04.009