Tuff

tuff -- n. A general term for consolidated rocks made of material ejected from volcanic explosions.
turbidite -- n. The sediments or rocks that formed as a result of a turbidity flow.

tuff A general term for all consolidated pyroclastic rock. Not to be confused with tufa.
turbidite Sedimentary deposit settled out of turbid water carrying particles of widely varying grade size. Characteristically displays graded bedding.

Tuff:
A rock composed of pyroclastic materials that have been ejected from a volcano. In many instances these fragments are still hot when they land, producing a "welded" rock mass.
Turbidite: ...

See also: Sandstone, Crust, Volcanic, Surface, Area