Peter Knight's Research on Glaciers
Dr. Peter G. Knight, School of Earth Sciences and Geography, Keele University, UK.
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  Research on basal ice in glaciers and ice sheets
  Using glacial sediments to reconstruct the basal ice characteristics of ancient glaciers

Overview
Research history
The Low-temperature Laboratory


Overview:
The broad aims of the research are to elucidate the processes by which basal ice is formed, and to use that knowledge to interpret glacial sediments and landforms. Different mechanisms of ice formation, ice diagenesis,  debris entrainment and structural deformation generate different physical and chemical characteristics in basal ice. If the relationship between the processes of formation and the characteristics of the ice can be identified, then the basal ice exposed at a glacier margin, or retrieved from a deep ice core, can  be used as an indicator of conditions in the inaccessible subglacial zone. In addition, if the basal ice characteristics of ancient glaciers such as those that existed in the UK can be reconstructed from the landforms and sediments they have left behind, then the characteristics of their subglacial environments might also be identified. Go HERE for some photos of basal ice.
 
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Research history:
I started research in glaciology in 1984, when I started working for my Ph.D in the Department of Geography, University of Aberdeen, with a NERC-funded research studentship under the supervision of David Sugden and Chalmers Clapperton. The project  was designed to ascertain the origin of the debris-bearing basal ice exposed in thick sequences at the margin of the Greenland ice sheet, and involved field observations at the Russell Glacier, near Kangerlussuaq,  Greenland. The thesis, examined by Geoffrey Boulton, was called  "On the origin of debris-bearing basal ice, West Greenland." Stratigraphic, isotopic (oxygen-18 and deuterium), structural, dynamic and sedimentological analyses of ice and debris from the ice-sheet margin indicated two zones of debris entrainment beneath the ice: one in the interior of the ice sheet and one close to the margin. These zones were  characterised by different entrainment processes, and hence produced different basal-ice characteristics. Go HERE for some photos of the field area.

Upon completion of the NERC studentship in 1987 I moved to the Department of Geography at Keele University, and continued to develop the work that was started with the PhD. The main results of  work stemming more or less directly from the PhD  were written up in a series of papers appearing between 1987 and 1994. Key papers from this period include:

At Keele, I developed  a low-temperature laboratory for glaciological research, and begun to combine field observations with experimental data to test theories about basal ice processes. This work received NERC funding for a project designed to conduct laboratory experiments on hypothetical processes of debris entrainment derived from field observations and theory. The results of that work  indicate the possibility of a previously undescribed mechanism of debris entrainment, involving the flow of water and fine-grained sediment through the intercrystalline network of veins that exists  in glacier ice. Work is now continuing to elucidate the mechanism and to explore its implications. Publications steming from this work include: After a University reorganisation in 1995 I became part of the Earth Surface Processes Research Group in the Department of Earth Sciences, and then the School of Earth Sciences and Geography, at Keele. However,  I  continued mainly to work independently or in collaboration with colleagues from other institutions. Much of my writing time from 1995-1999 was given over to preparing a new book "Glaciers", and to writing a number of review-cum-summation  papers, including: From 1998 onwards I started to work on my ideas of  using glacial sediments and landforms to reconstruct the basal ice characteristics of the glaciers that created them. This involved expanding my interests further into the pro-glacial zone, looking both at the recognition of former basal ice signatures in ice marginal sediments, at at sediment flux variations associated with ice-margin fluctuations. In 1999 I was awarded a research grant by the Royal Society for a new field-based project on this topic. The first results of this work were reported in:
Knight, P.G., Patterson, C.J., Waller, R.I., Jones, A.P. and Robinson, Z.P. (2000)  Preservation of basal-ice sediment texture in ice sheet moraines. QUATERNARY SCIENCE REVIEWS 19 (13), 1255-1258.
read whole paper     read abstract

Knight, P.G., Waller, R.I., Patterson, C.J., Jones, A.P. and Robinson, Z.P. (2000) Glacier advance, ice-marginal lakes and routing of meltwater and sediment: Russell Glacier, Greenland. JOURNAL OF GLACIOLOGY 46 (154), 423-426.
read abstract

Knight, P. G.,  Patterson, C. J., and Waller, R. I. (2001) Changes in sediment routing as a consequence of ice-sheet advance, Russell Glacier, Greenland. EOS, TRANS. AGU, 82 (47), Fall Meet. Suppl., Abstract. read abstract

Knight, P.G., Waller, R.I., Patterson, C.J., Jones, A.P. and Robinson, Z.P. (2002) Discharge of debris from ice at the margin of the Greenland ice sheet. JOURNAL OF GLACIOLOGY 48 (161), 192-198. read abstract
 

In 2000, I started to develop the "final stage" of my long-term research programme, looking at how basal ice signatures can be identified in formerly glaciated areas such as the UK, and possibly used to identify former subglacial conditions. This involves interests in the moraines marking the southern margin of the former Laurentide ice sheet (working in collaboration with Carrie Patterson) and in the glacial landforms of the English Lake District, as well as continuing work in Greenland with Richard Waller and postgraduate student Will Adam.

This work saw it's first published output with:

Adam, W.G. and Knight, P.G. (2003)   Identification of basal layer debris in ice-marginal moraines, Russell Glacier,West Greenland. QUATERNARY SCIENCE REVIEWS. (in press)   read paper (.pdf file)
At the same time, I continued to work on the problem of understanding basal ice formation at present day ice margins, especially at my longstanding field site in Greenland.

In 2003 I was awarded a new grant from the Leverhulme Trust to further develop my basal ice work. The new project involves a combination of field and laboratory work starting with a visit to southern Iceland in summer 2003 and funding Debbie Knight to work as a postdoctoral research assistant in the low-temperature laboratory. First results of this work were presented in Brussels in 2004, and there is more information about this project here. Publications based on this work in the Low-temperature laboratory include:

Knight, P.G. and Knight D.A. (in press, 2005) Laboratory observations of debris-bearing ice facies frozen from supercooled water. JOURNAL OF GLACIOLOGY

Knight, P.G. and Knight D.A. (2005) Laboratory observations of ice formation and debris entrainment by freezing turbid supercooled water. In Knight, P.G. (ed.) GLACIER SCIENCE AND ENVIRONMENTAL CHANGE (Blackwell, Oxford).

2003-5: Physical Geography at Keele underwent  further restructuring, including the appointments of Richard Waller and Zoe Robinson, with whom I was already collaborating, and the organisation of our research under the banner of "Subglacial and Ice Marginal Processes, Landforms and Environments" (SIMPLE) within the School of Physical and Geographical Sciences.
 

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The Low-Temperature Laboratory
The low-temperature laboratory was developed following my appointment to Keele in 1987. The need for the laboratory arose as a development of my fieldwork-based programme of glacial research. My research since then has combined field observations and laboratory experiments to understand subglacial processes. Field evidence for the internal characteristics of glaciers can be gathered from exposures of debris-bearing basal ice at glacier margins, but models built on this evidence are difficult to test in the field because of the inaccessibility of the subglacial zone. A low-temperature laboratory facility provides the opportunity to test both theoretically-derived and empirically-derived models of glacier processes in a convenient and controlled environment. The main subjects research have been the inaccessible subglacial zone and the englacial hydrological systems of glaciers. Research funded by NERC focussed on the transport of rock debris through the intergranular vein network of polycrystalline glacier ice, and research funded by The Leverhulme Trust focussed on the rapid freezing of supercooled water. In both of these projects Debbie Knight has been funded to work as a post-doctoral researcher in the Lab. Other work that I have supervised in the Lab has included parts of Paul Johnson's and Simon Cook's PhD projects, and a number of undergraduate dissertations.

There is  a tradition of laboratory experimentation in glaciology, but it has been confined largely to research in (i) ice physics and chemistry and (ii) simulation of flow and erosion processes. The programme of research being developed at Keele is unusual in that it aims to co-ordinate theoretical and empirical models through the experimental testing of model elements that are inaccessible in the field and cannot rigorously be tested in any other way.

Publications and presenations based on work in the low-temperature laboratory include

Knight, P.G. and Knight, D.A. (1994) Glacier sliding, regelation water flow, and development of basal ice. JOURNAL OF GLACIOLOGY 40 (136), 600-601. Click here for extracts

Knight, P.G. and Knight, D.A. (1999) Experimental observations of subglacial debris entrainment into the vein network of polycrystalline ice. GLACIAL GEOLOGY AND GEOMORPHOLOGY
Full paper: http://boris.qub.ac.uk/ggg/papers/full/1999/rp051999/rp05.html
Abstract: click here for abstract

Knight, P.G. and Knight, D.A. (2004)  Field observations and laboratory simulations of basal ice formed by freezing of supercooled subglacial water. Invited contribution to AMICS (Antarctic ice-sheet dynamics and climatic change: Modelling and Ice Composition Studies) workshop Dynamic Interaction between the Antarctic Ice Sheet and the Subglacial Environment, Vrije Universiteit Brussel, Brussels, April 2004. Sponsored by the Belgian Federal Science Policy Office (BELSPO). Details here

Knight, P.G. and Knight D.A. (in press, 2005) Laboratory observations of debris-bearing ice facies frozen from supercooled water. JOURNAL OF GLACIOLOGY

Knight, P.G. and Knight D.A. (2005) Laboratory observations of ice formation and debris entrainment by freezing turbid supercooled water. In Knight, P.G. (ed.) GLACIER SCIENCE AND ENVIRONMENTAL CHANGE (Blackwell, Oxford).

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