Big Pencils

These massive tillites take the fold-axis effect : Pencil Cleavage to new heights.


Trifarina said...

I don't get it. That looks like a tree trunk to me. learn me!

Fault Rocks said...

Yah no kidding! it is the hugest pencil ever. It is from the hinge of a fold where the cleavage and bedding are perpendicular to one another, effectively chopping the rock (in this case a silty diamictite) into long rods. They are usually small though.