I’ve been reading a fascinating book called Conversations with the Earth by Hans Cloos. I received the 1953 first edition copy from my uncle when I was in college. It sat on my shelf for years, and I never read it. Finally, I decided I needed to read it to decide if I wanted to keep it or not.
Besides the fact that it is a first edition, I want to keep this book. It’s a wonderful travelogue of the world as seen through the eyes of a geologist. Fascinating.
I learned something amazing by reading this book. Before he left for Africa, the author stopped in Naples, Italy. There he saw the Roman Macellum of Pozzuoli, three pillars that were built around the 2nd century AD. Here’s what is amazing.
The pillars are on dry land, but they have bands of boreholes from marine mollusks 27 feet up the pillars. Assuming they were built on dry ground, the land dropped and rose over 27 feet since 2 AD.
I’d never heard of the land moving like this before, so much in such little time. There is a name for this phenomenon. Bradyseism is the gradual uplift or descent of a section of land caused by the filling or emptying of an underground chamber. In the case of the pillars, the ground rises and lowers due to magma underground. The ground can also move due to variations in aquafers.
The Earth is an amazing place, and this is just one more reason why. Geologists often talk about landmasses moving millimeters a year and great change happening over millions of years. It is awesome to see geologic forces occurring on a human time scale.