Spire, Southern Utah

First Rocks and Farallon

The first event recorded in the rock of the Puente Hills began in the Mesozoic Era, some 245 million years ago (Ma). These rocks were formed when an oceanic plate …

Fault, Big Horn Mountains, Wyoming

Of Rock: Introduction

Overhead the sun coursed, time passed slowly but surely and underneath, tectonic plates floated on molten rock, bumping and grinding against each other, trying to fit but always failing. “Where …