BGS Rock Classification Scheme

Tuff, trachytic

Code TRTUF
Description Tuff, trachytic
Qualifiers trachytic      
Definition Lithified clastic material >10% debris formed by volcanic processes, >75vol% pyroclastic fragments, >75% ash <2mm; quartz <5% of QAPF, feldspar 65-90% alkali feldspar
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/TRTUF

CAVEAT

"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.