A

David

Darling

agglomerate

agglomerate, Kootznahoo Formation, Southeastern 
            Alaska

Agglomerate, Kootznahoo Formation, Southeastern Alaska. Credit: USGS.


Agglomerate is a coarse volcanic rock made up of both rounded and angular fragments of lava in a matrix of smaller, often ashy, particles. It thus combines the characteristics of conglomerates and breccias.