The stratigraphy of and well-completion reports for the Swanworth Quarry No. 1 and No. 2 and Metherhills No 1 boreholes (RGGE Project), Dorset

There has been increasing international awareness and concern in recent years about possible global climatic changes and their effects on local environments. In many of those parts of the world where detailed records have been kept for the last 50 to 100 years there is clear evidence of higher average summer temperatures, rising sea levels and a greater incidence of storms. The mechanisms behind these changes are not yet fully understood, and are likely to be complex. Increased emissions of carbon, nitrogen and sulphur oxides and hydrocarbon gases from transport and industrial processes are thought to have induced global climatic changes, but these changes are superimposed on natural changes that occur over time-scales that are too long for direct observation. For example, climatic changes related to variations in the radiant heat received from the sun are thought to occur as 2 1,000-year to 250,000-year cycles. The presence of such long-term climatic cycles can only be inferred from a detailed examination of the geological record. It was for this reason that the Natural Environment Research Council (NERC) decided in 1995 to allocate E900,OOO over 3 years to a special research topic, the Rapid Global Geological Events (RGGE) special topic, designed to examine in as great a detail as practicable a selected interval of the geological column. The aim is to apply to ancient sediments, analytical techniques used successfully to identify the effects of climatic changes in modem sediments. The Kimmeridge Clay was chosen by the RGGE Steering Committee (Chaired by Professor D J Vaughan, Manchester University) because it consists of an apparently unbroken sequence of highly fossiliferous marine mudstones, about 150 million years old, that represent about 3 million years of Earth history. The mudstones contain rhythmic variations in clay mineralogy, fauna and organic content that reflect climatic and sea-level changes. The aim of the project is to apply as many state-of-the art analytical methods as possible to a continuous core taken through the full thickness of the Kimmeridge Clay to enable these changes to be documented and the processes that cause them to be understood.