
thumb|Rocks from the Bishop tuff from California, United States, uncompressed with [[pumice on left; compressed with fiamme on right]] thumb|The caprock in this photo is the ignimbrite layer of the [[Rattlesnake Formation in Oregon.]]
thumb|Rocks from the Bishop tuff from California, United States, uncompressed with [[pumice on left; compressed with fiamme on right]] thumb|The caprock in this photo is the ignimbrite layer of the [[Rattlesnake Formation in Oregon.]]
Ignimbrite is a type of volcanic rock, consisting of a typically welded tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrounding atmosphere. New Zealand geologist Patrick Marshall (1869–1950) coined the term ignimbrite from the Latin igni- [fire] and imbri- [rain].
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).