Geology & Fossils
The Grand Canyon State is the only state nicknamed for a canyon. Carved by the Colorado River, the Grand Canyon, which forms part of Arizona’s northern border, is the ultimate symbol of the Colorado Plateau.
As you probably know, the Colorado Plateau is famous for its fossils. Two other geological regions converge in Arizona — the Basin and Range, and central highlands.
Yet Arizona isn’t as famous for fossils as other states in the West. This is largely because most fossil-bearing rocks in Arizona are older than the larger dinosaurs, the superstars of paleontology. Still, Arizona does boast a fabulous variety of fossils, from the trilobite trackways in the Grand Canyon in the north to the rudistid molluscs in the deep south at Pauls Spur.
Triassic Forests
One of the most famous fossil sites in the world is Arizona’s Petrified Forest National Park, a badlands carved out of the Colorado Plateau. The park is best known for the famous rainbow-hued fossilized wood that was adopted as Arizona’s state fossil.
But fossils of many other creatures that lived about 225 million years ago during the Triassic Period have also been found in Petrified Forest National Park. This was an age of great experiments, when bizarre animals evolved into dinosaurs or mammals or simply died out, leaving no descendants. Whimsical scientists have even coined such names as cowturtles, swinelizards, possumlizards, owliguanas, gatorlizards and wolf-crocodiles (a scary combination!). (Noting their close relationship with both birds and reptiles, one writer notes that early dinosaurs themselves might be called jaylizards.)
Other notable Arizona fossil sites include Christopher Creek and the Elephant Hill trackway. Christopher Creek is known for its strawberry-colored brachiopods (clam-like bivalves). They are probably reddish because of the iron in the sediments in which they were preserved.
The Ice Age Meets the Space Age
The Elephant Hill trackways preserves the tracks of mastodons, a camel, sloths and what may be a mountain lion. They are said to be some of the best preserved tracks of their kind in the United States.
One unusual Arizona fossil site has contributed greatly to our understanding of the extinction of the dinosaurs. It’s a meteor crater, known as the Barringer Meteor Crater, or simply “Meteor Crater.” (Technically, it should be called a Meteorite Crater.)
It might be scarcely noticeable in a tropical rain forest or high in some rugged mountain landscape. But Arizona’s meteor crater is exposed like an open wound on a limestone desert plain, stretching almost a mile across and nearly 600 feet deep. When Europeans first discovered the crater, over 30 tons of meteoritic iron lie scattered about the surrounding plain.
It is the best preserved meteor crater on Earth, even though people didn’t at first know what caused it. Scientists later studied the crater, which contributed greatly to our knowledge of the visitors from outer space we now know have visited Earth throughout history. Perhaps the most shocking revelation about Arizona’s meteor crater is its age: It struck Earth just 50,000 years ago!
Considering that the first hard-shelled animals evolved half a billion years ago (that’s 500,000,000), 50,000 years is but a blink of an eye.
The Shock Doctrine: The Rise of Disaster Capitalism - 
