Geology of the National Parks

GeoMations and GeoClips


About GeoMations

GeoMations are drawings that are captured as animations, narrated by Dr. Richard Alley and posted on YouTube for you to review at your own convenience.

The material in these drawings is almost never new—rather, it is a visual presentation of ideas and concepts you'll have already encountered in the readings and lectures. It's also important to note that these drawings are like the rest of the material presented to you in this class — that is, you should expect to be familiar with all the GeoMations in order to be successful in your weekly quizzes, just like you need to be familiar with the readings, the notes, the slide shows, and anything else included this week.

Death Valley

The great depth of Death Valley was not excavated by a steam shovel or an atomic bomb, nor were the rocks ground down by rivers, wind, or glaciers. Death Valley was dropped, as the sides of the valley were pulled apart as part of the great motions of the planet’s rocks. High drama indeed. Here is a brief description:


A person zipped into too-tight pants may “leak out” as the zipper is lowered. Baja California is being unzipped from the mainland of Mexico, and the leak is a volcano making new sea floor. If the unzipping continues, the sea might someday extend up toward or into Death Valley. Get a good grip on your zipper pull, and let’s go see.

Fault Types

You can push things together, pull them apart, slide them past each other - or some combination of pushing or pulling while sliding. Nature does the same, giving different types of faults, which are found in different geological settings. Here’s a quick look.


Dave Janesko, geologist, was one of the students on the CAUSE trip. Here, he and Dr. Alley explore the great Sevier Fault just west of Bryce Canyon in Utah. The pull-apart action that opened Death Valley actually affected a lot of the west, and is responsible for the Sevier Fault. The red limestone of Bryce was deposited in a lake. Much later, black lava flowed over the top and cooled. Then, the faulting occurred, and the black rocks were dropped to lie next to the red ones. Where the two meet along the nearly-vertical although slightly inclined fault, the red rocks show no sign of having been heated by the lava, so they must have been put together when cool. The red and black show near-vertical scratches, formed when the rocks slid past each other to get where they are now. So, join Dave on the fault.

CAUSE 2004 - The Fault Hunters

Want to see more?

Here are some optional videos and animations you might also want to explore! (No, these won't be on the quiz!)

The original "geyser" in Iceland
Yellowstone has roughly half of the world's geysers, but there are geysers in New Zealand, Iceland, and elsewhere. The original "geyser" is Geysir, in Iceland. Here is a short film clip of Geysir erupting, just for fun. Filmed by Vicki Miller.

Basic Plate Boundaries, scroll down the page to animation 2.6 to view.
(From Essentials of Geology by W. W. Norton and Company)

Plate Tectonic Movement Visualizations
(An extensive collection of animations on this subject)

San Francisco Earthquake Aftermath 1906
(Amazing film footage that is now 100 years old!! Click on one of the "View Movie" options on the left side of the new page to watch the 1:39 minute clip.)