Breccia

"Bølla" Breccia is 580 million years old. Breccias can have very different formation histories, but what they have in common is that these are rocks composed of fragments with sharp edges in a finer-grained matrix.

My real name is Birger. But many people think I’m a bit too eager to take part in everything! But isn’t it nice to be involved in a lot? Rockfalls, lava flows, mountain building-everything is fun! I have good acquaintances in all three main rock types. So the Breccia family can be sedimentary rocks, be transformed from something else, or be formed in connection with molten rock (magma). What’s typical for me, and what gives everyone in the Breccia family some common features, is that I am made up of somewhat angular fragments. Sometimes I can look like Kåre Conglomerate, but while he is made up of rounded and somewhat worn fragments, my pieces have sharper edges and can look more crushed.

Maybe I was once part of a landslide with sharp stones? And then the slide was pressed tightly enough together to become a rock? Or maybe I was a flow of molten rock that tore loose rock fragments on my way up through the crust? Or I was crushed between rock blocks as they were pressed against each other. And by the way… I might even be the result of a meteorite crash! I have some relatives like that up at Gardnos in Hallingdal.

FACTS:Breccias can have very different formation histories, but what they have in common is that these are rocks composed of fragments with sharp edges in a finer-grained matrix. They can form through the lithification of landslides and are thus sedimentary. Tectonic breccias can form when rocks are crushed during major movements in the Earth's crust. In connection with volcanism at Ulefoss 580 million years ago (the Fen Complex), some rocks show that molten rock has carried fragments of the rocks it intruded through (host rock), for example in damtjernite.