In June of this year, a scientific conference was held in Edinburgh, convened jointly by the Geological Society of America and the Geological Society of London. It was held in the rather grand surroundings of the new Edinburgh International Conference Centre and delegates came from far and wide to listen to the speakers, to take part in the excursions and to enjoy Edinburgh's June weather. The Edinburgh Geological Society helped with the organisation and ran a book store throughout the four days of the meeting. The following is a brief review by three British Geological Survey staff who attended a couple of the days.

This conference, described in the registration brochure as 'a global meeting', was designed to offer a holistic, interdisciplinary approach to understanding the way in which the Earth has evolved and to predict future change. It embraced many specialist fields and to describe it fully would take up several issues of this magazine. The Volume of Programmes with Abstracts runs to no less than 136 pages and readers who are interested would find it well worth dipping into. Copies are available in the BGS Library, Murchison House.

The following account represents impressions of just of two of the 58 sessions. These covered the highly topical issues of climate change in the Quaternary and global environmental change in the Late Palaeozoic. The application of modern research techniques to study change on different time-scales is vital to aid our understanding of how the Earth works. The predictable headline-driven press coverage - 'Did a planetary wobble kill the dinosaurs?' New Scientist, 28th June 2001, 'Could a Seismic Fault Account for Loch Ness's Mysterious Monster?' Scientific American, 27th June 2001, and similar stories in the daily newspapers at least advertised the conference [for details see website www.geosociety.org/meetings/edinburgh/index.htm]. For the scientists attending, it achieved the aim of bringing together specialists from a wide range of disciplines to analyse past and emergent Earth surface processes.

Day 1 - 25th June

After introductions to Life on Earth and Earth Systems from Aubrey Manning and Geoffrey Boulton during the plenary session, Session No. 5, Causes of rapid climate change in the Quaternary got underway. Mark Maslin of University College, London presented a well-informed summary of the nature of climate transition during the Quaternary and the problems that can be encountered in this field. The idea of climate transition thresholds was discussed, and the principle of 'bifurcation' in climate responses. The resultant non-linear relationships mean that climate changes are unlikely to reverse in the same way as they originally occurred. Problems of spatial and temporaral sca1e were addressed, and was linked to interactions of tectonics, atmospheric gases and orbital forcing mechanisms.
A number of speakers continued the theme, highlighting particular aspects of Quaternary climate change. William Hay of the GEOMAR Research Centre, Kiel, presented more detailed assessments of factors such as Carbon 4 plants and their impact on atmospheric CO₂ and aridity; tectonics such as Cenozoic uplift of the Tibetan plateau; and volcanic emissions. G.H. Haug of ETH, Zurich, presented El NÓno data from tropical South America with a discussion of worldwide climate impacts of the southward migration of Inter-Tropical Convergence Zone. Thermohaline circulation in the North Atlantic and its control on mass ice-rafting events such as Heinrich 1 was dealt with by Michel Crucifix of the Universite Catholique de Louvain, whilst Gideon Henderson of Oxford University presented U/Th midpoint dates for the last three major deglaciations, based on carbonate sediments from the Bahamas.

During the afternoon session, Fragile and hazardous environments, two speakers, Magnus Gudmundsson of the University of Iceland and Andrew Russell of Keele University, spoke on Icelandic jokulhlaups. Gudmundsson focussed on fundamental processes and environmental impacts whilst Russell presented data suggesting the common occurrence of large-scale ice-fracturing and englacial sediment depostion during these events. Mary Chapman of the USGS used such Icelandic phenomenon as an analogue for Martian landsystems observed in images from the most recent Mars Orbiter Mission. Outlet canyons of jökulhlaups on the Martian surface appear to extend for up to 3000 km.

Posters for each of the sessions were on display throughout the day. Of particular interest were posters from Katherine Leonard of Portland State University and Jeremy Everest of Edinburgh University, both of which demonstrated new Quaternary techniques. Leonard presented a technique for the micromorphological study of unconsolidated aeolian sand using surfboard resin for the preparation of thin sections. After in situ impregnation and a curing time of one or two days, the sediment is then removed from the field locality with a greatly reduced risk of damage. However, it may only be successful in fully dry, unconsolidated coarse-grained material, and may not be so useful in wet sediments or silt and clay-rich tills. Everest presented results of cosmogenic dating of boulder surfaces from moraines in the Cairngorms. Large errors in the dates reflect the high number of corrections that need to be made with this technique, but those presented at least provide a 'ball-park' figure for deglaciation of Gleann Einich and the surrounding area of around 16 000 to 14 500 years BP.

Day 2 - 26th June

In the plenary session The geological consequences of evolution Andrew Knoll of Harvard University discussed the effects of the environment on evolution and vice versa. This concept was developed with the modern interaction between humans and the environment as we alter our environments to suit our own physiology. The consequences of such interactions are to alter evolution as well as the environments around us.

In Session No. 25 Global change in the Late Palaeozoic, Chris Scotese of the University of Texas presented 3D palaeogeographic reconstructions of Late Palaeozoic continents and ocean basins. This proved to be a stimulating and animated discussion of current global reconstructions. It got off to a lively start with inflatable balls representing different epochs within the Palaeozoic being dispersed amongst the audience. Presentations of working palaeo-digital elevation models from five dates within the Late Palaeozoic followed, and Chris tackled current palaeogeographical controversies such as the timing of the North American continent crossing the equator during the Devonian and Carboniferous.

A number of speakers discussed the analysis of isotopes and their relationship to environmental change. Topics included isotopic whole rock and organic carbon trends in relation to environmental cycles and events. Werner Buggisch of the Univeristy of Erlangen concluded that the d¹³C isotope curve can be correlated to the sea level and to (bio-)events in Europe. However, further investigation is required from this research to assess if the shifts in the isotope curve are global. Using evidence gathered from two basalt flows of different ages Robert Berner of Yale University suggested that the rise of trees and vesicular plants around 360 Ma coincided with a rapid decrease in CO₂ due to a rise in weathering and the burial of organic matter. Matthew Saltzmann of Ohio State University studied the Carboniferous sequence in the Arrow Canyon Range in Nevada to indicate the transitions between Greenhouse and Icehouse phases. The patterns of the carbon curve may be controlled by the effect of glaciation on sea level. d¹³C values are seen to increase throughout the Carboniferous with an anomaly in the earliest Carboniferous. Based on numerous comparisons from North America and Belgium, this shift is apparently global, and may be linked to the closing of the Euramerican and Gondwanan gateways. Ethan Grossman of Texas A & M University analysed carbon isotope variation in brachiopod samples from the Russian Platform, North America and Australia. Although the quality of the data was debatable, the main conclusions were:

• in continental USA, d¹⁶O may reflect regional salinity variations, especially during the early Carboniferous;
• there is evidence for coupling between the Carbon cycle and the Permo-Carboniferous palaeoclimate.

As can be seen, the conference provided a forum for a wide range of presentations. Another topic that commanded much interest was the Snowball Earth Theory, but the ice was broken early in the conference at the beer and poster sessions. Although the consequences of the Foot and Mouth epidemic put paid to most of the planned excursions, some enjoyed the volcanic delights of Arthur's Seat made even more dramatic by a local thunder storm.

Acknowledgement

This review is published by permission of the Director, British Geological Survey (NERC).