#volcanic rocks
- Alunitization — A geological process of acid hydrothermal alteration of volcanic or magmatic rocks rich in feldspars, under the action of ascending solutions charged with sulfuric acid; the act of transforming into alunite. This structural phenomenon leads to the replacement of primary minerals with alunite, quartz, and kaolinite, constituting a valuable indicator in geological prospecting for metalliferous deposits.
- Andesitic — Belonging to andesite, relating to andesite, or having the composition, structure, and characteristics specific to this effusive igneous rock. In petrography, it describes magmas, lavas, tuffs, or volcanic flows with an intermediate silica content, characteristic of tectonic subduction zones.