OLISTOSTROME

An 'olistostrome' is a sedimentary deposit composed of a chaotic mass of heterogeneous material, such as blocks and mud, that accumulates as a semifluid body by submarine gravity sliding or slumping of the unconsolidated sediments. It is a mapable stratigraphic unit which lacks true bedding, but is intercalated amongst normal bedding sequences, as in the Tertiary basin of central Sicily.
Olistostromes are mélanges formed by gravitational sliding under water and accumulation of flow as a semi fluid body with no bedding.