breksias

Breccia is a type of sedimentary or volcanic rock characterized by its angular fragments cemented together within a matrix. The fragments, which are typically larger than 2 millimeters in diameter, are angular and broken, indicating they have not been transported far from their source. The matrix is a finer-grained material that fills the spaces between the larger clasts. Breccias can form in various geological settings. Sedimentary breccias often originate from rockfalls, landslides, or debris flows where large, angular blocks are deposited close to their origin. They can also form in fault zones through the grinding and crushing of rock during seismic activity, creating tectonic breccias. Volcanic breccias are produced by explosive volcanic eruptions, where fragmented volcanic material, including rocks and ash, is ejected and then consolidates. The composition of a breccia depends entirely on the source rocks from which its fragments and matrix are derived. Their appearance can vary greatly, from coarse and poorly sorted to finer-grained variations.