Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down.
Two of the largest known impact events on Earth occurred during the Orosirian. Early in the period, 2023 Mya, a large asteroid collision created the Vredefort impact structure. The event that created the Sudbury Basin structure occurred near the end of the period, 1850 Mya.
Breccia (Wikipedia) Breccia (/ˈbrɛtʃiə, ˈbrɛʃ-/) is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
