Sedimentology, which deals with the geology of sedimentary deposits, has become an actively studied discipline parallel to the development of academic and industrial drilling programs, research on plate tectonic concepts and environmental considerations. Continuous series such as those provided by the Deep Sea Drilling Project or the Ocean Drilling Program constitute outstanding archives to reconstruct environmental conditions governing past seas and adjacent landmasses.

The noun sediment comes to the English language from the Latin root sedimentum, meaning settling or sinking down,aform ofthe verb sedere,to sit orsettle. In earth and environmental sciences, sediment has a wide context that includes many forms of organic and mineral matter. In Part 1 we look more deeply at the origins of the sediment that occurs on and under the surface of the solid planets and which may be used to infer past environmental conditions and changes. Sediment accumulations may be grandly viewed as the great stratal archive of past surface environments, or more basically as‘dirt’. There has been sediment on the surface of the Earth since the Archaean, with the oldest known sediment grains dating from at least 4.4Ga (Part 1 Fig. 1). Sediment also mantles the surface of many other planets and their satellites, notably Mars, Venus and Saturn’s moon, Titan. <...>

The theme of this Memoir originated with the 11th Congress of the International Association of Sedimentologists held at McMaster University, Hamilton, Canada during August 1982. It was in March 1979 that a University of Saskatchewan colleague, Hugh E. Hendry and myself proposed to the Congress Organizing Committee that a comprehensive synthesis of current knowledge on conglomeratic sediments was timely. This proposal materialised into a 12-day symposium, chaired by the present co-editors, of 29 oral papers with published abstracts — 14 of which became material for this Memoir. 

The examination into the sediments of the Western Guiana shelf, the results. of which are recorded in the present report forms part of the study of the continental shelf deposits off the Orinoco delta. The initiative to this investigation was taken by Prof. Dr Ph. H. KUENEN, Director of the Institute of Marine Geology of Groningen University (Holland); the ‘“‘Bataafsche Petroleum Maatschappij N.V.” of The Hague, by their support, have rendered the necessary expeditions possible. The area of investigation, lying off the Orinoco delta in the N.E. of South America, extends from the Venezuelan Testigos Islands in the N.W. to the shelf area off the Essequibo river mouth in British Guiana in the S.E., from nearshore up to the region of the shelf edge (Fig. 1). <...>