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My main research interests are glacial and hazard geomorphology. More specifically, my research focuses on the formation, evolution and drainage of ice-dammed lakes and the impact of associated glacial outburst floods or 'jökulhlaups'. Over the past few years I have been collaborating with a number of researchers both in the UK and overseas; most of this work has involved field research in Iceland and the Scottish Highlands and is related to jökulhlaups, glacial sediment entrainment and palaeo-environmental reconstruction. I have worked on natural hazards, risk and vulnerability as part of a European Commission funded project designed to harmonise the mapping of natural hazards for land-use planning.
My principal areas of teaching are geomorphological processes and landforms and natural hazards. As well as teaching through the usual means of lectures, practical workshops, seminars and tutorials, I am committed to fieldwork as an effective learning and teaching environment for undergraduates and have supervised over 40 residential fieldcourses to-date, both in the U.K. and overseas. I am also enthusiastic about embedding research-informed teaching in the undergraduate curriculum.
Address: Geography
Staffordshire University
Leek Road
Stoke-on-Trent
Staffordshire
ST4 2DF
UK
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Papers by Fiona Tweed Local Environment , 2011
... Fiona Tweed a * & Gordon Walker b Available online: 07 Nov 2011. ... View all references,... more ... Fiona Tweed a * & Gordon Walker b Available online: 07 Nov 2011. ... View all references, While et al. 200931. While, A., Jonas, AEG and Gibbs, D. 2009. From sustainable development to carbon control: eco-state restructuring and the politics of urban and regional development. ...
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Journal of Geography in Higher Education , 2011
The links between research and teaching have been the subject of much debate and controversy over... more The links between research and teaching have been the subject of much debate and controversy over the need for both activities to take place in universities remains current. This paper reports on the development and evaluation of a research placement module, which aimed to provide opportunities for students to work as research assistants on small-scale projects. This paper outlines the
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Quaternary Science Reviews , 2010
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Journal of Geography in Higher Education , 2010
This paper reports an adaptation of a classroom-based, traditionally taught module to both facili... more This paper reports an adaptation of a classroom-based, traditionally taught module to both facilitate field-based knowledge acquisition and contribute towards research. The module enabled students, through a combination of new research and co-learning, to achieve the original ...
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Earth Surface Processes and Landforms , 2009
A number of theoretical, conceptual and numerical models exist for de-glacial controls on volcani... more A number of theoretical, conceptual and numerical models exist for de-glacial controls on volcanism, but geological evidence is scarce. We describe and explain a regional topographic and geomorphic expression of sub-glacial volcanism, namely that at Kverkfjöll, Iceland. This area comprises a series of parallel sub-glacially-erupted volcanic edifices, which together give excellent 3D geological exposure. These ridges are orientated north-south or along the most probable line of LGM ice margin retreat. We combine topographic and geomorphic observations to explain the changing style of volcanism in space, and attribute this to the recession and downwasting of the LGM ice sheet. Specifically, we observe that there is no spatial pattern to pillow lava edifice heights or volumes, indicating that fissure eruptions beneath the LGM ice sheet were of similar dynamics in space. However, hyaloclastite and hyalotuff deposits are restricted to proximal and high elevation positions. Furthermore, lithofacies are split by erosional contacts and hyalotuffs are faulted and intruded. These observations together suggest that as the overlying ice sheet became thinner volcanic activity became more explosive. Volcanic activity also appears to have ‘retreated’ towards the Kverkfjöll central volcano. Glacial outburst floods or ‘jökulhlaups’ were prevalent during de-glaciation, partly because sub-glacial meltwater could not be impounded due to the high gradient bedrock topography. For northern Iceland, our proposed sequence of landscape development suggests two major glacial advances during the Holocene, at least one of which at Kverkfjöll probably coincided with volcanic activity and a jökulhlaup. Future work should look to establish an absolute dating control and/or chronology. Copyright © 2009 John Wiley & Sons, Ltd.
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Quaternary Science Reviews , 2007
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Geomorphology , 2006
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Geomorphology , 2006
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Annals of Glaciology , 2005
Abstract: This paper explores changing ice-water interactions during jökulhlaups from Grænalón, a... more Abstract: This paper explores changing ice-water interactions during jökulhlaups from Grænalón, a 5× 10 8 m 3 subaerial lake dammed by Skeiðarárjökull, Iceland. Unstable drainage of Graenalón since the early 20th century has resulted in 45 jökulhlaups whose hydrologic character has varied enormously. Geomorphic observations and geophysical measurements from the inlet and outlet zones of the subglacial floodwater tract constrained the hydromechanical factors governing ice-water interactions at Grænalón. To date, three ...
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Quaternary Science Reviews , 2005
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Developments in Quaternary Science , 2005
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Sedimentary Geology , 2004
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Geomorphology , 2004
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Earth Surface Processes and Landforms , 2003
Glacial outburst floods (jökulhlaups) occur frequently in glaciated environments, and the resultan... more Glacial outburst floods (jökulhlaups) occur frequently in glaciated environments, and the resultant flooding causes geomorphic change and, in some instances, damage to local infrastructure. During some jökulhlaups, floodwater is stored temporarily in ice-marginal locations. In July 1999, a linearly rising jökulhlaup burst from Sólheimajökull, Iceland. During this remarkable event, subglacial floodwater pooled transiently in two relict ice-dammed lake basins, before draining suddenly back into Sólheimajökull. The significance of such rapid formation and attendant drainage of temporary ice-dammed lakes during jökulhlaups has not been addressed. Consequently, this paper: (i) assesses the hydrologic and geomorphic effects of temporary ice-dammed lake formation caused by lake-basin ‘retro-filling’; and (ii) discusses the impact and significance of transient retro-filling under jökulhlaup conditions. Pre- and post-flood fieldwork at Sólheimajökull enabled the impact and significance of lake-basin retro-filling to be assessed. Field evidence demonstrates that the July 1999 jökulhlaup had an unusually rapid rise to peak discharge, resulting in subglacial floodwater being purged to ice-marginal locations. The propensity for temporary retro-filling was controlled by rapid expulsion of floodwater from Sólheimajökull, coincident with locations suitable for floodwater storage. Floodwater inundated both ice-marginal lake basins, permitting significant volumes of sediment deposition. Coarse-grained deltas prograding from the ice margin and boulders perched on scoured bedrock provide geomorphic records of sudden retro-filling. The depositional characteristics of lake-basin deposits at Sólheimajökull are similar to jökulhlaup sediments documented in proglacial settings elsewhere; however, their depositional setting and association with ice-marginal landforms is distinctive. Findings suggest that temporary ice-dammed lake formation and drainage has the capacity to alter the shape of the flood hydrograph, especially if drainage of a temporary lake is superimposed on the original jökulhlaup. Deposits associated with lake-basin retro-filling have a long-term preservation potential that could help to identify temporary ice-dammed lake formation in modern and ancient glacial environments. Copyright © 2003 John Wiley & Sons, Ltd.
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Geografiska Annaler Series A-physical Geography , 2004
... acknowledged. Rosie Duncan (Staffordshire University) prepared the il-lustrations. Tim Harris... more ... acknowledged. Rosie Duncan (Staffordshire University) prepared the il-lustrations. Tim Harris, Fiona Tweed, Department of Geogra-phy, Staffordshire University, Stoke-on-Trent, Staf-fordshire, ST4 2DE, UK. Email: tdharris@staffs.ac.uk ...
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Journal of Quaternary Science , 2003
This paper examines the origin and significance of Loch Lomond Stadial (Younger Dryas) gravel dep... more This paper examines the origin and significance of Loch Lomond Stadial (Younger Dryas) gravel deposits at Creag Aoil, Spean Bridge, Scotland. Sedimentation into ice-dammed lakes in Glen Roy and Glen Spean associated with shorelines at 260 m, 325 m and 350 m is well-documented, yet little is known about later, lower level lakes near Spean Bridge. Excavations on the northern flanks of the Lundy Channel revealed exposures into a 35–40 m thickness of sand and gravel. These sediments reflect deposition in a subaqueous environment experiencing repeated short-lived periods of high-energy subaerial deposition. Deformation structures within subaqueous deposits are associated with at least two ice-push events. This study presents new evidence for the existence of ice-dammed lakes at elevations between 260 m and 113 m and for periodic jökulhlaups draining southwest via the Lundy Channel. Active glacier ice associated with the deposits flowed northwest to southeast, driving meltwater across the Great Glen to the Lundy Channel. Glacier retreat was punctuated by periodic minor readvances. Progressive ice retreat was accompanied by ice thinning, and changes in ice-flow direction and subglacial meltwater routing. These findings add to knowledge of Loch Lomond Stadial deglaciation around Spean Bridge and have implications for our understanding of lacustrine glacier margins during deglaciation. Copyright © 2003 John Wiley & Sons, Ltd.
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Geology , 2002
Abstract We present evidence of glaciohydraulic supercooling under jökulhlaup and ablation-domina... more Abstract We present evidence of glaciohydraulic supercooling under jökulhlaup and ablation-dominated conditions from two temperate Icelandic glaciers. Observations show that freezing of sediment-laden meltwater leads to intraglacial debris entrainment during normal and extreme hydrologic regimes. Intraglacial frazil ice propagation under normal ablation-dominated conditions can trap copious volumes of sediment, which forms anomalously thick sections of debris-rich ice. Glaciohydraulic supercooling plays an ...
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Earth Surface Processes and Landforms , 2001
This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaup... more This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaups. Previous studies of jökulhlaup sedimentology have focused predominantly on proglacial impact, rather than depositional processes within glaciers. However, observations of supraglacial floodwater outbursts suggest that englacial sediment emplacement is possible during jökulhlaups. The November 1996 jökulhlaup from Skeiđarárjökull, Iceland presented one of the first opportunities to examine englacial flood deposits in relation to former supraglacial outlets. Using observations from Skeiđarárjökull, this paper identifies and explains controls on the deposition of englacial flood sediments and presents a qualitative model for englacial jökulhlaup deposition. Englacial jökulhlaup deposits were contained within complex networks of upglacier-dipping fractures. Simultaneous englacial deposition of fines and boulder-sized sediment demonstrates that englacial fracture discharge had a high transport capacity. Fracture geometry was an important control on the architecture of englacial jökulhlaup deposits. The occurrence of pervasively frozen flood deposits within Skeiđarárjökull is attributed to freeze-on by glaciohydraulic supercooling. Floodwater, flowing subglacially or through upglacier-dipping fractures, would have supercooled as it was raised to the surface faster than its pressure-melting point could increase as glaciostatic pressure decreased. Evidence for floodwater contact with the glacier bed is supported by the ubiquitous occurrence of sheared diamict rip-ups and intra-clasts of basal ice within jökulhlaup fractures, deposited englacially some 200–350 m above the bed of Skeiđarárjökull. Evidence for fluidal supercooled sediment accretion is apparent within stratified sands, deposited englacially at exceptionally high angles of rest in the absence of post-depositional disturbance. Such primary sediment structures cannot be explained unless sediment is progressively accreted to opposing fracture walls. Ice retreat from areas of former supraglacial outbursts revealed distinct ridges characterized by localized upwellings of sediment-rich floodwater. These deposits are an important addition to current models of englacial sedimentation and demonstrate the potential for post-jökulhlaup landform development. Copyright © 2001 John Wiley & Sons, Ltd.
Bookmarks Related papers Mentions View impact
Earth Surface Processes and Landforms , 2000
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Geology Today , 2000
An unpredicted sudden outburst flood from Sólheimajökull, Southern Iceland, in July 1999 may hera... more An unpredicted sudden outburst flood from Sólheimajökull, Southern Iceland, in July 1999 may herald a major subglacial volcanic eruption beneath Mýrdalsjökull ice cap.
Bookmarks Related papers Mentions View impact
Local Environment , 2011
... Fiona Tweed a * & Gordon Walker b Available online: 07 Nov 2011. ... View all references,... more ... Fiona Tweed a * & Gordon Walker b Available online: 07 Nov 2011. ... View all references, While et al. 200931. While, A., Jonas, AEG and Gibbs, D. 2009. From sustainable development to carbon control: eco-state restructuring and the politics of urban and regional development. ...
Bookmarks Related papers Mentions View impact
Journal of Geography in Higher Education , 2011
The links between research and teaching have been the subject of much debate and controversy over... more The links between research and teaching have been the subject of much debate and controversy over the need for both activities to take place in universities remains current. This paper reports on the development and evaluation of a research placement module, which aimed to provide opportunities for students to work as research assistants on small-scale projects. This paper outlines the
Bookmarks Related papers Mentions View impact
Quaternary Science Reviews , 2010
Bookmarks Related papers Mentions View impact
Journal of Geography in Higher Education , 2010
This paper reports an adaptation of a classroom-based, traditionally taught module to both facili... more This paper reports an adaptation of a classroom-based, traditionally taught module to both facilitate field-based knowledge acquisition and contribute towards research. The module enabled students, through a combination of new research and co-learning, to achieve the original ...
Bookmarks Related papers Mentions View impact
Earth Surface Processes and Landforms , 2009
A number of theoretical, conceptual and numerical models exist for de-glacial controls on volcani... more A number of theoretical, conceptual and numerical models exist for de-glacial controls on volcanism, but geological evidence is scarce. We describe and explain a regional topographic and geomorphic expression of sub-glacial volcanism, namely that at Kverkfjöll, Iceland. This area comprises a series of parallel sub-glacially-erupted volcanic edifices, which together give excellent 3D geological exposure. These ridges are orientated north-south or along the most probable line of LGM ice margin retreat. We combine topographic and geomorphic observations to explain the changing style of volcanism in space, and attribute this to the recession and downwasting of the LGM ice sheet. Specifically, we observe that there is no spatial pattern to pillow lava edifice heights or volumes, indicating that fissure eruptions beneath the LGM ice sheet were of similar dynamics in space. However, hyaloclastite and hyalotuff deposits are restricted to proximal and high elevation positions. Furthermore, lithofacies are split by erosional contacts and hyalotuffs are faulted and intruded. These observations together suggest that as the overlying ice sheet became thinner volcanic activity became more explosive. Volcanic activity also appears to have ‘retreated’ towards the Kverkfjöll central volcano. Glacial outburst floods or ‘jökulhlaups’ were prevalent during de-glaciation, partly because sub-glacial meltwater could not be impounded due to the high gradient bedrock topography. For northern Iceland, our proposed sequence of landscape development suggests two major glacial advances during the Holocene, at least one of which at Kverkfjöll probably coincided with volcanic activity and a jökulhlaup. Future work should look to establish an absolute dating control and/or chronology. Copyright © 2009 John Wiley & Sons, Ltd.
Bookmarks Related papers Mentions View impact
Quaternary Science Reviews , 2007
Bookmarks Related papers Mentions View impact
Geomorphology , 2006
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Geomorphology , 2006
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Annals of Glaciology , 2005
Abstract: This paper explores changing ice-water interactions during jökulhlaups from Grænalón, a... more Abstract: This paper explores changing ice-water interactions during jökulhlaups from Grænalón, a 5× 10 8 m 3 subaerial lake dammed by Skeiðarárjökull, Iceland. Unstable drainage of Graenalón since the early 20th century has resulted in 45 jökulhlaups whose hydrologic character has varied enormously. Geomorphic observations and geophysical measurements from the inlet and outlet zones of the subglacial floodwater tract constrained the hydromechanical factors governing ice-water interactions at Grænalón. To date, three ...
Bookmarks Related papers Mentions View impact
Quaternary Science Reviews , 2005
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Developments in Quaternary Science , 2005
Bookmarks Related papers Mentions View impact
Sedimentary Geology , 2004
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Geomorphology , 2004
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Earth Surface Processes and Landforms , 2003
Glacial outburst floods (jökulhlaups) occur frequently in glaciated environments, and the resultan... more Glacial outburst floods (jökulhlaups) occur frequently in glaciated environments, and the resultant flooding causes geomorphic change and, in some instances, damage to local infrastructure. During some jökulhlaups, floodwater is stored temporarily in ice-marginal locations. In July 1999, a linearly rising jökulhlaup burst from Sólheimajökull, Iceland. During this remarkable event, subglacial floodwater pooled transiently in two relict ice-dammed lake basins, before draining suddenly back into Sólheimajökull. The significance of such rapid formation and attendant drainage of temporary ice-dammed lakes during jökulhlaups has not been addressed. Consequently, this paper: (i) assesses the hydrologic and geomorphic effects of temporary ice-dammed lake formation caused by lake-basin ‘retro-filling’; and (ii) discusses the impact and significance of transient retro-filling under jökulhlaup conditions. Pre- and post-flood fieldwork at Sólheimajökull enabled the impact and significance of lake-basin retro-filling to be assessed. Field evidence demonstrates that the July 1999 jökulhlaup had an unusually rapid rise to peak discharge, resulting in subglacial floodwater being purged to ice-marginal locations. The propensity for temporary retro-filling was controlled by rapid expulsion of floodwater from Sólheimajökull, coincident with locations suitable for floodwater storage. Floodwater inundated both ice-marginal lake basins, permitting significant volumes of sediment deposition. Coarse-grained deltas prograding from the ice margin and boulders perched on scoured bedrock provide geomorphic records of sudden retro-filling. The depositional characteristics of lake-basin deposits at Sólheimajökull are similar to jökulhlaup sediments documented in proglacial settings elsewhere; however, their depositional setting and association with ice-marginal landforms is distinctive. Findings suggest that temporary ice-dammed lake formation and drainage has the capacity to alter the shape of the flood hydrograph, especially if drainage of a temporary lake is superimposed on the original jökulhlaup. Deposits associated with lake-basin retro-filling have a long-term preservation potential that could help to identify temporary ice-dammed lake formation in modern and ancient glacial environments. Copyright © 2003 John Wiley & Sons, Ltd.
Bookmarks Related papers Mentions View impact
Geografiska Annaler Series A-physical Geography , 2004
... acknowledged. Rosie Duncan (Staffordshire University) prepared the il-lustrations. Tim Harris... more ... acknowledged. Rosie Duncan (Staffordshire University) prepared the il-lustrations. Tim Harris, Fiona Tweed, Department of Geogra-phy, Staffordshire University, Stoke-on-Trent, Staf-fordshire, ST4 2DE, UK. Email: tdharris@staffs.ac.uk ...
Bookmarks Related papers Mentions View impact
Journal of Quaternary Science , 2003
This paper examines the origin and significance of Loch Lomond Stadial (Younger Dryas) gravel dep... more This paper examines the origin and significance of Loch Lomond Stadial (Younger Dryas) gravel deposits at Creag Aoil, Spean Bridge, Scotland. Sedimentation into ice-dammed lakes in Glen Roy and Glen Spean associated with shorelines at 260 m, 325 m and 350 m is well-documented, yet little is known about later, lower level lakes near Spean Bridge. Excavations on the northern flanks of the Lundy Channel revealed exposures into a 35–40 m thickness of sand and gravel. These sediments reflect deposition in a subaqueous environment experiencing repeated short-lived periods of high-energy subaerial deposition. Deformation structures within subaqueous deposits are associated with at least two ice-push events. This study presents new evidence for the existence of ice-dammed lakes at elevations between 260 m and 113 m and for periodic jökulhlaups draining southwest via the Lundy Channel. Active glacier ice associated with the deposits flowed northwest to southeast, driving meltwater across the Great Glen to the Lundy Channel. Glacier retreat was punctuated by periodic minor readvances. Progressive ice retreat was accompanied by ice thinning, and changes in ice-flow direction and subglacial meltwater routing. These findings add to knowledge of Loch Lomond Stadial deglaciation around Spean Bridge and have implications for our understanding of lacustrine glacier margins during deglaciation. Copyright © 2003 John Wiley & Sons, Ltd.
Bookmarks Related papers Mentions View impact
Geology , 2002
Abstract We present evidence of glaciohydraulic supercooling under jökulhlaup and ablation-domina... more Abstract We present evidence of glaciohydraulic supercooling under jökulhlaup and ablation-dominated conditions from two temperate Icelandic glaciers. Observations show that freezing of sediment-laden meltwater leads to intraglacial debris entrainment during normal and extreme hydrologic regimes. Intraglacial frazil ice propagation under normal ablation-dominated conditions can trap copious volumes of sediment, which forms anomalously thick sections of debris-rich ice. Glaciohydraulic supercooling plays an ...
Bookmarks Related papers Mentions View impact
Earth Surface Processes and Landforms , 2001
This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaup... more This paper presents sedimentary evidence for rapid englacial debris entrainment during jökulhlaups. Previous studies of jökulhlaup sedimentology have focused predominantly on proglacial impact, rather than depositional processes within glaciers. However, observations of supraglacial floodwater outbursts suggest that englacial sediment emplacement is possible during jökulhlaups. The November 1996 jökulhlaup from Skeiđarárjökull, Iceland presented one of the first opportunities to examine englacial flood deposits in relation to former supraglacial outlets. Using observations from Skeiđarárjökull, this paper identifies and explains controls on the deposition of englacial flood sediments and presents a qualitative model for englacial jökulhlaup deposition. Englacial jökulhlaup deposits were contained within complex networks of upglacier-dipping fractures. Simultaneous englacial deposition of fines and boulder-sized sediment demonstrates that englacial fracture discharge had a high transport capacity. Fracture geometry was an important control on the architecture of englacial jökulhlaup deposits. The occurrence of pervasively frozen flood deposits within Skeiđarárjökull is attributed to freeze-on by glaciohydraulic supercooling. Floodwater, flowing subglacially or through upglacier-dipping fractures, would have supercooled as it was raised to the surface faster than its pressure-melting point could increase as glaciostatic pressure decreased. Evidence for floodwater contact with the glacier bed is supported by the ubiquitous occurrence of sheared diamict rip-ups and intra-clasts of basal ice within jökulhlaup fractures, deposited englacially some 200–350 m above the bed of Skeiđarárjökull. Evidence for fluidal supercooled sediment accretion is apparent within stratified sands, deposited englacially at exceptionally high angles of rest in the absence of post-depositional disturbance. Such primary sediment structures cannot be explained unless sediment is progressively accreted to opposing fracture walls. Ice retreat from areas of former supraglacial outbursts revealed distinct ridges characterized by localized upwellings of sediment-rich floodwater. These deposits are an important addition to current models of englacial sedimentation and demonstrate the potential for post-jökulhlaup landform development. Copyright © 2001 John Wiley & Sons, Ltd.
Bookmarks Related papers Mentions View impact
Earth Surface Processes and Landforms , 2000
Bookmarks Related papers Mentions View impact
Geology Today , 2000
An unpredicted sudden outburst flood from Sólheimajökull, Southern Iceland, in July 1999 may hera... more An unpredicted sudden outburst flood from Sólheimajökull, Southern Iceland, in July 1999 may herald a major subglacial volcanic eruption beneath Mýrdalsjökull ice cap.
Bookmarks Related papers Mentions View impact
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Papers by Fiona Tweed