Look up: ignimbrite

1. ignimbrite
   rock composed of compacted volcanic ejecta (see tuff).[2 related articles]
   Found on http://www.britannica.com/eb/a-z/i/7
   
   
2. Ignimbrite
   The rock formed by the widespread deposition and consolidation of ash flows and Nuees Ardentes. The term was originally applied only to densely welded deposits but now includes non-welded deposits.
   Found on http://volcano.oregonstate.edu/education
   
   
3. Ignimbrite
   , uncompressed with pumice on left; compressed with fiamme on right. An `ignimbrite` is the deposit of a pyroclastic density current, or pyroclastic flow, a hot suspension of particles and gases that flows rapidly from a volcano, driven by a greater density than the surrounding atmosphere. Ignimbrit...
   Found on http://en.wikipedia.org/wiki/Ignimbrite