Marine Geophysical Researches 22: 303–308, 2001. © 2002 Kluwer Academic Publishers. Printed in the Netherlands. 303 Seismic expression of contourites and related deposits: a preface Michele Rebesco 1,* and Dorrik Stow 2 1 Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Dipartimento di Geofisica della Litosfera, Borgo Grotta Gigante 42/C, 34010 Sgonico (Trieste), Italy; 2 Southampton Oceanography Centre, School of Ocean and Earth Science, University of Southampton, Waterfront Campus, Southampton SO14 3ZH, UK; * Author for correspondence (Fax: +39-040-327307; E-mail: mrebesco@ogs.trieste.it) Received 11 December 2001; accepted 21 December 2001 Key words: contourites, diagnostic criteria, drift types, geometry, seismics Abstract Contourites are widespread throughout the deep sea, ranging from those that build up individually distinct bodies (mounded drifts) to those that occur closely interbedded with other deep-water facies. Although seismic data should not be used to make a firm identification of contourites without supporting evidence, much progress has been made in determining the combination of seismic criteria that best represent contourite deposits. With some modifications and additions, these criteria are in broad agreement with those recently proposed by Faugères and colleagues (1999). The papers in this special issue are mainly drawn from those presented at an IGCP workshop held in Trieste, Italy (October 2000), together with selected additions. Some of the new and important topics covered include: discussion of bottom-current controlled deposits on continental shelves and in large lakes (shallow-water and lacustrine ‘contourites’); the unique characteristics of high-latitude contourite systems that show interaction with turbidity current, debris flow and glacigenic processes; and the importance of local slope topography, developed as a result of synsedimentary tectonics and downslope mass movement, in focussing and shaping drift deposits (infill and fault-related drifts). An introduction to the powerful use of 3D seismic data in understanding contourite systems points the way towards important future research. Introduction Volume aims This preface aims to introduce the volume, to briefly summarise the contributions, to address some of the problems presented by the authors and to provide an updated list of seismic criteria for the recognition of contourites. The purpose of the volume is to pro- vide geologists and geophysicists, especially those involved in bottom current research, paleoceanogra- phy and hydrocarbon exploration, a comprehensive, updated collection of well documented case-histories that allows a substantial improvement in: (1) defining a set of seismic characteristics of con- tourite drift deposits; (2) elucidating the criteria by which contourites can be distinguished from other related deep-water de- posits; (3) standardising terminology and constructive method- ology for seismic contourite research; (4) understanding less well studied and poorly classi- fied drift systems (e.g. mixed, high-latitude, shallow marine, or lacustrine drifts). In order to better achieve these goals the Editors of this Special Volume required as crucial that the pro- posed contributions: (1) focused on seismic characteristics of contourite and related systems; (2) provided good quality seismic or other acoustic data; (3) referred to or included supporting data of other kinds; (4) carefully considered valid interpretations and alternative possibilities; (5) emphasised innovative aspects in their examination of conventional contourite systems or presented new data from less well-known drift systems. Contourites: distribution and importance Contourites are sediments deposited or substantially reworked in deep water by the action of bottom cur- rents. First observed in the 1960s along the eastern North American continental margin, they are now