Breccia

Breccia is a rock made of angular fragments of older rocks bound by a finer-grained matrix or mineral cement. Its angular clasts distinguish it from conglomerate, whose clasts are rounded.

Clast: A fragment of a pre-existing rock or mineral incorporated into a sediment or rock. Breccia is defined by the angular shape of its constituent clasts.
Sedimentary breccia: Breccia formed when angular fragments accumulate and become lithified as sediment. Deposition and burial can preserve angular debris as sedimentary breccia.
Mechanical weathering: The physical breakdown of rock into smaller pieces without changing its chemical composition. Physical breakdown can generate the angular fragments found in breccia.
Fault zone: A region of fractured and displaced rock surrounding a geological fault. Breccia within a fault zone records brittle deformation and movement.
Diamictite: A poorly sorted sedimentary rock containing particles across a wide range of sizes in a finer matrix. Diamictite is defined by poor sorting, not by the angular clasts characteristic of breccia.
Matrix (geology): The finer-grained material surrounding larger grains or fragments in a rock. Breccia fragments may be supported by a fine-grained matrix.
Fault breccia: Breccia produced when rocks fracture and grind along a fault zone. Fault movement breaks bedrock into angular fragments that may later cement.
Rockfall: The rapid descent of detached rock fragments down a steep slope or cliff. Rockfalls create angular debris that may accumulate and become breccia.
Volcanic eruption: The release of magma, gases, and fragmented material from a volcano. Volcanic breccia can preserve evidence of eruption style and fragmentation.
Conglomeratic sandstone: A sandstone containing a notable proportion of gravel-sized grains or pebbles. Its finer-grained framework contrasts with the coarse fragment-dominated texture of breccia.

Linked from 2 pages