PBS Eons has a new episode on the Great Unconformity, which is a massive gap in sedimentary rocks worldwide.  This event might help to explain what brought about the evolution of biomineralization… think bones, teeth, shells, etc.

In some places, the rocks below the Great Unconformity are about 1.2 billion years older than those above it. This missing chapter in Earth’s history might be linked to a fracturing supercontinent, out-of-control glaciers, and maybe the diversification of life itself.