What sedimentary rock is made of fragments of rock with jagged edges?

1 Answer
Dec 18, 2015



Breccia is a rock made up of differently sized fragments cemented together. The fragments are said to be angular, which means they have pointy or jagged surfaces.

This rock is thought to form in river systems, where eroded fragments of pre-existing rocks accumulate in a shallow basin. The angular nature of the fragments suggests that they are not carried far from the original rocks. As rocks are carried further in a river, they bump into other rocks and become rounder, like they're in a tumbler. There is a rock called conglomerate, which is also formed in rivers but contains very round fragments. Breccia is made of the fragments that don't make it very far downstream, so are eroded less.