Abstract The current volume samples a selection of papers presented at the Geological Society of London meeting on ‘Biogeochemical Controls on Palaeoceanographic Proxies’, held at Burlington House, London, UK on 3–4 October 2005. The aim of the meeting was to bring together palaeontologists, geochemists and palaeoceanographers who could contribute evidence that, when considered together, would better constrain the proxies that are used for palaeoclimate reconstruction. An improved understanding and quantification of past climatechange, and the processes that force climate to change, has a fundamental role to play in constraining model projections of future climate (e.g. Hegerlet al. 2006) but it remains a huge challenge. This is because key climate variables, such as temperature and ocean salinity, cannot be observed in a world which no longer exists, but must instead be teased from proxies in the geological and ice records. There are numerous proxy archives, but one of the most important, currently lying at the forefront of palaeoceanographic research, is the biogeochemical composition of sediment records. This publication consists of 11 papers which deal with various aspects of biogeochemical proxies and their interpretation in terms of past climate. Seven of these specifically focus on the Foraminifera. What are proxies? Primarily, these are biogenic components which have a closerelationship to environmental parameters and maybe identified as so-called ‘proxy variables’ (Weferet al. 1999), providing measurable descriptors of key climatic and environmental variables. The methods commonly employed in palaeoceanography have their origins in the biological, chemical and physical sciences; palaeoceanography therefore represents a relatively young and truly crossdisciplinary field of research. At the time of writing, an excellent new book entitled Proxiesin Late Cenozoic Paleoceanography has been published (Hillaire-Marcel De Vernal 2007), providing a comprehensive review of the subject.

Abstract Scientific observations of our oceans and climate go back no more than a couple of hundred years. Most of our information about the evolution of Earth's ocean-climate system relies instead on proxies – primarily measurements of sediment components that respond to changes in environmental parameters. This paper provides an overview of some of the most important biological and geochemical proxies and outlines their contribution to our understanding of the ocean-climate system. We also discuss some of the challenges that need to be overcome to obtain accurate records. These include: better understanding of the controls on the mechanisms of biomineralization; the impacts of post-depositional dissolution and diagenesis on primary proxy relationships; proxy validation; and analytical considerations.