8 August 2012

Armored mud balls

Posted by Callan Bentley

At Devil’s Coulee in Alberta, there are dinosaur bones and Western Interior Seaway clamshell fossils — yawn.

What really got me excited, though, were the armored mud balls!

This phenomenon is as intuitive as it is bizarre. After a big rain, a glob of sticky, self-cohesive mud gets weathered out of the badlands. The globule goes tumbling down hill, where it encounters pebbles. The pebbles (and strands of grass, and grasshoppers, I suppose) stick to (and are partially mashed into) the exterior of the mud ball.

Eventually, it can attain a nice layer of exterior “armor” like an Ankylosaur. Here’s a different view (rotated a bit in perspective, and zoomed in) on that same armored mudball… Note the mudcracks!

A parting shot: two for one!

This was my first time seeing real live armored mud balls in the field. It was a thrill and a half!