ABSTRACT
VOLCANICLASTIC sediments are those composed mainly of grains and clasts derived from contemporaneous volcanic activity. They are a common part of many sedimentary successions and particularly dominant in active plate-tectonic settings. Some authors use the terms volcanogenic or pyroclastic as synonymous with volcaniclastic deposits (or volcaniclastites). However, the former implies a broader suite including extrusive volcanic rocks, and the latter is used here in a more restricted sense (see below).
