Geomorphology and geomorphological responses to climate change in the interior of sub-Antarctic Marion Island

dc.contributor.advisorSumner, P.D. (Paul)
dc.contributor.coadvisorMeiklejohn, K.I. (Ian)
dc.contributor.emailhedding@uniwest.ac.zaen
dc.contributor.postgraduateHedding, David Williamen
dc.date.accessioned2013-09-07T02:06:08Z
dc.date.available2007-07-03en
dc.date.available2013-09-07T02:06:08Z
dc.date.created2006-01-21en
dc.date.issued2006en
dc.date.submitted2007-07-03en
dc.descriptionDissertation (MSc)--University of Pretoria, 2006.en
dc.description.abstractThe influence of climate change on the geomorphology of the interior of Marion Island (above 750m a.s.l.) is investigated as climatic amelioration is thought to be responsible for the observed rapid melt out of the summit regions. Records have shown that the climate on Marion Island is warming and, as it represents a maritime periglacial environment characterised by small seasonal temperature ranges and steep temperature profiles, it is particularly sensitive to climate change. Marion Island is, therefore, an ideal location to address the poor understanding of periglacial environments in the Southern Circumpolar Region in the context of environmental conditions governing permafrost, seasonally frozen ground, and frost processes. To ascertain the influence of climatic amelioration on the geomorphology of Marion Island’s interior, thermokarst, periglacial, and rudimentary aeolian features were identified and mapped. Geomorphological features were documented to determine the extent of landscape response to climate change in the island’s interior. In addition, identification and mapping of geomorphological features were, in some cases, used to provide evidence for the previous existence of permafrost. Ground temperatures were also monitored to determine the present state and possible existence of permafrost above 750m a.s.l. Landscape development in the certain areas of the interior of Marion Island where glacial ice persists beneath sediment (scoria) and where permafrost previously existed has resulted in the manifestation of thermokarst features and the creation of a unique undulating topography. In parts of the study area, thermal erosion and subsidence of the thermokarst are identified as processes that are important agents of landscape evolution. Thermokarst processes, indicative of climate change are, however, limited to areas where buried glacial ice persists and permafrost existed. Thermokarst features studied were also noted to be ephemeral and easily destroyed through erosion by wind and water. Aeolian erosion, in particular, has a significant influence on thermokarst as the interior of the island represents a polar desert where almost no vegetation survives. Persistence of thermokarst features is further limited due to the nature of local sediment, namely scoria, being cohesionless, thereby limiting the retention of water that can be frozen. The disappearance of the former permanent snowline sub-aerially exposing much of the interior suggests interaction between frost and aeolian processes will provide potentially relevant avenues for future geomorphological research. Furthermore, interactions between frost and aeolian processes are extremely important for plant colonisation in an area that is almost entirely devoid of vegetation.en
dc.description.availabilityUnrestricteden
dc.description.degreeMSc
dc.description.departmentGeography, Geoinformatics and Meteorologyen
dc.identifier.citationHedding, DW 2006, Geomorphology and geomorphological responses to climate change in the interior of sub-Antarctic Marion Island, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/26025>en
dc.identifier.upetdurlhttp://upetd.up.ac.za/thesis/available/etd-07032007-144008/en
dc.identifier.urihttp://hdl.handle.net/2263/26025
dc.language.isoen
dc.publisherUniversity of Pretoriaen_ZA
dc.rights© 2006, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.en
dc.subjectUCTDen_US
dc.titleGeomorphology and geomorphological responses to climate change in the interior of sub-Antarctic Marion Islanden
dc.typeDissertationen

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