Awards Ceremony 2015 – senior medallists’ talks
Lyell Medal (Colin Ballantyne – Professor, School of Geography and Geosciences, University of St
Andrews)
Catastrophic landslides in Scotland and Ireland: timing, causes and implications
Scottish and Irish mountains contain over 700 major postglacial rock-slope failures (RSFs). Exposure
dating of 31 RSFs using cosmogenic 10Be and 36Cl shows that they occurred over the period 18.2 ± 1.2
to 1.7 ± 0.2 ka, but were 4.6 times more frequent during the Lateglacial period (>11.6 ka) than
during the Holocene, with peak RSF activity 1600–1700 years after ice-sheet deglaciation. This time
lag is inferred to represent deglacial stress release leading to progressive failure plane development,
and ultimately to spontaneous kinematic release or failure triggered by some extrinsic mechanism.
The timing of most RSFs coincides with maximum rates of glacio-isostatic recovery, suggesting that
earthquakes were important triggers of rockslide release. The prevalence of ‘pre-last glaciation’ RSF
scars lacking runout debris demonstrates that rockslides made a major contribution to the sediment
budget of former ice sheets and glaciers, and suggests that the erosive role of Pleistocene ice sheets
has been over-emphasised: perhaps glaciers mainly ‘clean up the mess’ left by landslides in
steepland terrain.
Murchison Medal (Geoffrey Wadge – Professorial Research Fellow, Department of Meteorology,
University of Reading)
Volcanoes and Radars
The products and effects of a volcanic eruption are often not observed or measured because it is
night, it is too dangerous to get close or the volcano is hidden in cloud. So the ideal instrument to
overcome this is one that uses its own illumination, can image from many kilometres away and see
through cloud – which are all things that a radar does. Over the last 20 years radars on the ground
and in space have been used to measure an increasing range of volcanic phenomena: lava forming
flows and domes, pyroclastic flows and explosions. Radar interferometry can miraculously measure
millimetric levels of ground motion associated with magma movement below the surface over
periods of weeks to months. Over the next 20 years there should be radars in geostationary orbit in
space that can effectively stare at volcanoes all the time.
William Smith Medal (Anthony Doré OBE – Senior Advisor to Exploration Management at Statoil)
The Arctic, and the dark art of regional geology
It is perhaps not too fanciful to state that William Smith was the first great regional geologist.
Essentially he did for the first time what modern regional geologists do, by collating information
from widely scattered sources of variable reliability, and using them to propose a credible and
testable picture - in this case, his great map. Regional geologists occupy an interesting niche in that
they do not necessarily have to be involved in field work, laboratory measurement or even
modelling. Rather they beg, borrow and steal from all of these sources and attempt to weld them
into a new whole – a fuzzy picture that can be sharpened, tested and modified as new data arrives.
So regional geology is a Dark Art, but can also lead us down pathways that are important both
academically and economically. I will illustrate this principle with examples from a regional study of
the Arctic, one of the last great frontier provinces where much of the fundamental geology is still
highly debated. I will show how taking a holistic approach, and understanding the co-evolution of
the basins bordering the Arctic Ocean, allows testable predictions to be made for unexplored areas.
Wollaston Medal (James Jackson – Head of Department of Earth Sciences, University of
Cambridge)
Probing the continents: how deep structure affects surface geology
Over the last decade advances in earthquake seismology have allowed us to make increasingly
detailed maps of the variations in lithosphere (plate) thickness on the continents. The variations are
dramatic, with some places up to 300 km thick, and clearly relate to the geological history of the
continents as well as their present-day deformation. Though the horizontal resolution of the maps
is currently about 200 km, that is still sufficient to show that many features apparently isolated in
the middle of continents, such as intracratonic basins, intraplate earthquakes and volcanism, are in
fact either within or on the edge of thick lithosphere, and correlate also with variations in plate
strength that control the scale of geological structures and stratigraphy.