EDITORIAL 1437 Copyright © 2004 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 29, 1437–1440 (2004) Earth Surface Processes and Landforms Earth Surf. Process. Landforms 29, 1437–1440 (2004) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/esp.1131 EDITORIAL: TERRESTRIAL GEOCHEMICAL SEDIMENTS AND GEOMORPHOLOGY SUE J. MCLAREN, 1 * DAVID J. NASH 2 AND ANDREW S. GOUDIE 3 1 Department of Geography, University of Leicester, University Road, Leicester, LE1 7RH, UK 2 School of the Environment, University of Brighton, Lewes Road, Brighton, BN2 4GJ, UK 3 School of Geography and the Environment, University of Oxford, Mansfield Road, Oxford, OX1 3TB, UK The papers within this special issue focus upon research undertaken by members of the British Geomorphological Research Group (BGRG) Terrestrial Geochemical Sediments & Geomorphology Working Group. The group was established at the end of April 2001, with a primary aim of developing a network for UK and other European Earth scientists working on the diverse range of terrestrial geochemical sediments (which includes deposits such as calcrete, silcrete, gypcrete, ferricrete, aeolianite, terrestrial evaporites, speleothems and rock coatings) in order to share knowledge and expertise. Since its inception, the group has convened symposia at the European Union of Geosciences XIth Biennial Conference (Strasbourg 2001) and two BGRG Annual Conferences (University of Nottingham 2001, University of Oxford 2003), as well as workshops at the universities of Brighton (2002) and Leicester (2004). The group currently has over thirty members, including sedimentologists, geomorphologists and geochemists from the UK, France, Ireland, Norway and Australia. The Terrestrial Geochemical Sediments & Geomorphology Working Group has two key scientific objectives: • to gain a better understanding of the influence of landscape setting upon the formation of terrestrial geochemical sediments; • to establish the variability of the long-term preservation potential of geomorphological features in the environ- ment as a result of diagenetic processes. The papers presented here reflect the first of these objectives, and arise from the Working Group meetings held at Nottingham (2001) and Brighton (2002). The studies have been chosen to represent topical research issues concerning the processes and products of geochemical sedimentation and their relationship to the landscape. They include extensive field- and laboratory-based studies in environments that currently range from temperate, through to wet sub-tropical, semi-arid, arid and hyper-arid. The research topics addressed include carbonate cementation of aeolianites, case-hardening of sandstones, the development of raised beach deposits, formation of gypsiferous sediments and crusts, and the factors influencing the genesis of calcretes, silcretes and calcrete– silcrete intergrade duricrusts. The first paper by McLaren and Gardner studies the influence of climate upon processes of vadose diagenesis within aeolian and raised beach sands. The authors examined deposits from a range of locations including Libya, Oman, the Mediterranean, the Caribbean and Mexico, covering present-day climatic environments from hyper- arid through to wet sub-tropical. McLaren and Gardner found that, under certain conditions, a climatic signal could be recognized, with greater amounts of diagenetic alteration occurring in deposits of similar ages from wetter environments in comparison to more arid zones. However, the effects of climate can either be enhanced or lost in areas where other controls predominate (such as processes that operate within a rhizosphere, sea spray zone or close to the groundwater table). The paper emphasizes the problems of misinterpretation that can be made if overly simplistic relationships between vadose diagenesis and climate are assumed. The second paper, by Drake et al., investigates the origins of gypsum deposits from southern Tunisia, focusing upon the identification of * Correspondence to: S. McLaren, Department of Geography, University of Leicester, University Road, Leicester LE1 7RH, UK. E-mail: sjm11@le.ac.uk