A guide to the use of volcaniclastic nomenclature in engineering investigations

Current good practice in geology is to identify volcaniclastic rocks using a descriptive classification scheme. The terms agglomerate, volcanic breccia and tuff are currently used in both a descriptive and genetic sense, in BS 5930 (1999). However, the definitions used are now considered incorrect in both senses. This technical contribution redefines these terms and places them in a modern geological context. A new descriptive classification scheme for identifying and naming volcaniclastic rocks is proposed that will assist engineering geological descriptions of these rock types.