Friday Rock Blogging: Columnar Basalt
Waterfall and Columnar Basalt © Joe Decker. Used with permission.
I finally found a piece from my nature photographer friend Joe Decker that would make a suitable subject for rock blogging. Y’see, the problem with fine art photographers is that they often forget to do things like add a rock hammer for scale. Also, they can have entire portfolio sections devoted to the Carrizo Plain without once showing an offset stream channel! It must be a very strange way to see the world.
Anyway, this image is of part of a lava flow in Iceland. As a new blanket of rock cools, it contracts. If it cools evenly and slowly enough, this contraction will create regular hexagonal columns. The phenomenon is famous at places like Devil’s Postpile and the Giant’s Causeway.