Fiamme textures in volcanic successions: Flaming issues of definition and interpretation

Abstract

Fiamme are aligned, “flame-like” lenses found in welded ignimbrite. Fiamme also occur in welded pyroclastic fall deposits, secondary welded pumice-rich facies, diagenetically altered and compacted non-welded, pumiceous, volcaniclastic facies and lavas. Fiamme can be formed in a variety of ways. The common genetic use of the term fiamme for pumice clasts that have undergone welding compaction is too narrow. “Fiamme“ is best used as a descriptive term for elongate lenses or domains of the same mineralogy, texture and composition, which define a pre-tectonic foliation, and are separated by domains of different mineralogy, texture or composition. This descriptive term can be used regardless of the origin of the texture, and remains appropriate for flattened pumice clasts in welded ignimbrite.