Geological History of the Southwest
At the beginning, Earth was a mass of molten rock with no continents, oceans, life or oxygen. As time went by, the Earth cooled enough so that a hard layer formed at the surface. This crust was not even, but broke up into plates due to forces in the mantle below. Some of these plates formed the continents, others the ocerans. Most of what we see today in the Sonoran Desert, the Southwest and elsewhere is a result of movements of these plates around the Earth, colliding and separating from each other as they went.
Follow along with Bob as he describes the changes that have taken place over the last 2.5 billion years and explains the forces involved in mountain building, volcanism and creation of landforms in general, and see what might be in store for the future. His lively discussion and unique hand-drawn figures make a complex and difficult subject accessible and exciting.
The discussion is organized into sections each related to a particular Figure number. These Figures can be accessed at any time by clicking on links throughout the text. For those who want to pursue some aspects that were touched on by Bob, he has provided a list of books dealing with a number of interesting related subjects.