Late Triassic scene in Blue Mesa Room, Rainbow Forest Museum
Blue Mesa Room, Rainbow Forest Museum


Triassic Period
~227-205 million years ago

Imagine a large river basin with numerous rivers and streams flowing through the lowland. Galleries of trees, ferns, and giant horsetails grow abundantly along the waterway, providing food and shelter for many insects, reptiles, amphibians, and other creatures. In the slightly dryer areas a short distance from the water there are cycads, ginkgoes, and coniferous trees towering almost two-hundred feet into the sky. If you can picture such a river basin, then you can imagine Petrified Forest's environment over 200 million years ago.

During the Triassic, the climate was very different from that of today. Located near the equator about where Costa Rica is now, this region was humid and tropical. The landscape was dominated by a river system larger than anything on Earth today. Giant reptiles, amphibians, early dinosaurs, fish, and many invertebrates lived among the dense vegetation and in the winding waterways.

Look at Ron Blakey's paleogeography maps to visualize how Petrified Forest's global position has changed since the Triassic. What about your own home?

On-going paleontological research in the park broadens our understanding of the world long ago. Check out our Science & Research page to learn more.

Last updated: August 1, 2021

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Petrified Forest National Park
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Petrified Forest, AZ 86028-2217


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