Texas A&M University (TAMU) GEOL101 Principles of Geology Exam 1 Practice Exam

Breccia is a sedimentary rock that is characterized by its composition of angular fragments. The angularity of the fragments indicates that they have not been subjected to extensive transport or weathering; consequently, they retain their sharp edges. This typically occurs in environments where the rock fragments are deposited close to their source, such as landslide areas or fault zones where debris accumulates rapidly.

In contrast, conglomerate consists of rounded fragments that have been worn smooth, suggesting a longer transport distance where the particles have been subjected to water or wind erosion. Siltstone and shale are both composed of finer particles – siltstone from silt-sized particles and shale from clay-sized particles – which do not involve visible fragments, let alone angular ones. Therefore, breccia is the correct answer due to its distinct feature of composed angular fragments, indicating a specific formation process that differentiates it from other sedimentary rock types.