The above illustration will help you visualize the internal rock layers of the Grand Canyon in northern Arizona. The vertical "slice" on the left shows layers of color that match the actual geological layers in the photo to the right. Imagine that we have taken a knife and cut a vertical "slice" in the north rim of the canyon and then we have rotated this slice to the left, as illustrated, revealing the internal structure.

This, then, is an elementary introduction to the geology of the Grand Canyon.

Enjoy! Click on the ALBUM pages below:

Table of Contents

• Where is the Grand Canyon?
• The Grand Canyon from Space
• Erosion and the 2 Colorado Rivers
• Learning the Names of the Geological Layers
• The Supergroup - The Deeper Layers
• Identifying Typical Southwest Landforms
• Ancient Environments - Prehistoric Life!

Some thoughts on the Grand Canyon

Herein we will talk about water at great length as we add interpretive illustrations to this section. There is foremost, of course, the Colorado River itself with its power to downcut through all these layers of rock. Then there is the erosion of side canyons and its accompanying debree flow, always trying to keep up (or down) with the river's channel. We'll show you how this creates the rapids the river is famous for. We'll explain why we've included the Little Colorado River Basin in this story, for it remains the primary source today for silt and natural flood behavior that is vital for sandbars and the river's health. We'll talk about our episodical climate. When water comes as rain or snow around here it comes in episodes, often in large amounts. And when we talk about erosion in the Grand Canyon, we'll have to include the power of frost action in modern times. Throughout the Colorado Plateau it is likely to freeze at night seven months out of the year. This is a major force that breaks down solid rock at an amazing rate. The story of the canyon is very much the story of water and climate.

It is the premise of this presentation, that this huge local network of canyons and riverbeds, built over eons of time, established the patterns for all life that followed. This erosional feature, more obvious when seen from space, created corridors, barriers and aspects that influenced every living thing, including humans, in the passing of time. We will create several illustrated lessons here, as "Interpretive Field Notes," that will tell stories about the geology, the flora and the fauna of these canyons.

To the visitor this area of the southwest can seem barren and filled with huge emptiness. But the more you know, the more your trips can be a banquet.

As of March of 2000 this presentation was recognized by these home school associations.

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