a) Remote monitoring groundwater fluctuations and groundwater-channel relationships beneath an Icelandic glacier. Work that has involved Rebecca Lunn, Patrik Vidstrand and Segei Zatsepin, that currently involves remote, telemetric monitoring of groundwater levels in boreholes beneath, at and beyond the margin of Breidamerjurjökull in S.E. Iceland, together with occasional seasonal monitoring of the discharges of a major stream and seasonal streams that discharge from the central part of a subglacial groundwater catchment. Some relevant recent publications are:
- Boulton, G.S. and Zatsepin, S. December 2006. Hydraulic impacts of glacier advance over a sediment bed. Journal of Glaciology, 52 (179), 31pp.
- Boulton, G.S., Lunn, R., Vidstrand. P. and Zatsepin, S. March 2007. Subglacial drainage by groundwater-channel coupling, and the origin of esker systems: Part I – Glaciological observations,. Quaternary Science Reviews, 26, 1067-1090.
- Boulton, G.S., Lunn, R., Vidstrand. P. and Zatsepin, S. March 2007. Subglacial drainage by groundwater-channel coupling, and the origin of esker systems: Part II – Theory and simulation of a modern system. Quaternary Science Reviews, 26, 1091-1105.
b) Drainage processes in former ice sheets and the formation of “tunnel valleys”. We are unable directly to observe the large-scale patterns of drainage beneath modern glaciers, but we can observe the evidence of large-scale patterns of drainage associated with former ice sheets. Magnus Hagdorn, Sergei Zatsepin, Bertrand Maillot and I have attempted to both establish some patterns and to explain them. We have argued that groundwater flow plays a fundamental role in determining the frequency and location of major drainage streams. Some relevant recent publications are:
- Boulton, G.S. 2006. Ice sheets and their coupling with hydraulic and sedimentary processes, 10-29. In Knight, P. (ed) Glaciers and Environmental Change, Blackwell, Oxford.
- Boulton, G.S., M. Hagdorn, M., Maillot, P.B. and Zatsepin, S. 2009. Drainage beneath ice sheets: groundwater–channel coupling, and the origin of esker systems from former ice sheets. Quaternary Science Reviews 28, 621-638.
- Boulton, G.S. 2010. Drainage pathways beneath ice sheets and their implications for ice sheet form and flow: the example of the British Ice Sheet during the Last Glacial Maximum. Journal of Quaternary Science 25(4), 483-500.
c) Subglacial Sediment processes and properties. Studying subglacial sedimentation is most productive when the results of remote monitoring of contemporary processes in modern glaciers are combined with direct observations of the properties of sediments produced by former glaciation. This complementary approaches are being pursued in Antarctica and Andorra: Antarctica. Giorgos Papageorgiou, Andy Smith and I are using the fact of repeated remote surveys over many years of the bed of the Rutford ice stream in West Antarctica, beneath 1 km of ice, to establish sediment properties and processes using active and passive seismic and radar. This is made particularly exciting because of the drumlins previously identified beneath the ice stream by Andy and his colleagues from the British Antarctic Survey. We have precisely mapped the location of the boundary between deforming and non-deforming sediments, how acoustic emissions reflect smooth deformation and stick-slip displacement respectively, defined a “deformation front” between the deforming and non-deforming areas, established the relationship between drumlins and sediment properties, and shown the drumlins to be multi-phase features. The hydraulic state of the system (see a) above) is clearly the key determinant of the dynamic of this system. Andorra. Valenti Turu and I have exploited the enormous amount of detailed geotechnical data from the heavily built-up floor of the Gran Valira to map consolidation patterns in the sequence of tills separated by fluvio- and limno-fluvial sediments that make up the thick sedimentary sequence on the valley floor. Coupling this with groundwater flow modelling shows how the deduced patterns of pre-consolidation can only be explained as a result of a series of glacial consolidation events, and that later events do not overprint consolidation patterns du to earlier events. Results also show the controlling influence of the geometry of the subglacial groundwater catchments.
Some emerging conclusions are contained in:
- Boulton, G., Papageorgiou, G., Smith, A., King, E., Wright D., Doyle S. and Smith E. (in press 2014). Sediment dynamics and drumlin evolution beneath an Antarctic ice stream.
- Papageorgiou, G., Boulton G. and Smith A. (in press 2014). Characterising subglacial sediments beneath an Antarctic ice stream using amplitude versus offset (AVO) inversion.
- Turu I Michels, V., Boulton, G.S., Ros I Visus, X., Peña-Monné, J.L., Marti I Bono, C., Bordonau I Ibern, J., Serrano-Canadas, E., Sancho-Marcen, C., Constante-Orrios, A., Pous I Fabregas, J., Gonzalez-Trueba, J.J., Palomar i Molins, J., Herrero I Simon, R. and J.M. Garcia-Ruiz. 2007. Structures des grandes basins glaciaires dans le nord de la Péninsule Ibérique. Quaternaire, 18, 309-325.