The Birds and the Beads: February 2016

Petrified Forest National Park continues to fascinate. A weather prediction of an unseasonably warm 55-degree day plus calm winds (what is a calm wind, really? But I digress) enticed us back to explore a part of the Park suggested by our previous hike leader, Gary. Gary gave us general instructions to park just south of this one pull-out here, look for a derelict old two-track road there, follow it to nearby hills, and find an old trail that switches from being visible to nonexistent a few times. And, he added, when in doubt, just wander back in the general direction of your vehicle. No problem.

We would be exploring an area known as the Blue Forest. The popular Blue Mesa loop drive and its associated paved trail would be visible at one point along our walk, as it hugs the east side of Blue Forest. However, we'd be exploring the interior area coming from the west, touching upon that paved trail for a short distance, then veering off again to wander further.

We found our pullout and the derelict two-track road, with Blue Forest in the distance. A sign indicated we were at the right pullout, as it aptly described the importance of the area we were entering.

A closer look at part of our hiking destination.

Since I can't do better than that interpretive sign, I'll repeat it verbatim:

"In the summer of 1921, heiress and explorer Annie Montague Alexander and her research partner Louise Kellogg set off into the badlands in front of you. Intrigued by fossils discovered by John Muir fifteen years earlier, Annie and Louise unearthed numerous specimens including phytosaurs and metoposaurs. The work of these women pioneered the science of vertebrate paleontology in Petrified Forest National Park. They were assisted by Dr. Charles Camp from the University of California's Museum of Paleontology, a museum that was founded by Alexander in 1921. Camp went on to work in the area for nearly a decade."

Annie Alexander, ca 1921. Cool lady, no?

The sign continues: "Since that time, research teams from organizations such as the American Museum of Natural History and the Smithsonian Institute have worked in the Blue Forest collecting fossil vertebrates. Annie Alexander's legacy lives on through the work of scientists who continue to make discoveries here about life in the Late Triassic." Wow. A couple female paleontologists in the early 1920's exploring this part of Arizona? Hats off; color me impressed!

The interpretive sign shows an image of Annie's camp in the Blue Forest:

And examples of skulls (a reptile and an amphibian) unearthed in this area:

Almost verbatim from the sign at the Tepees pullout, across the road: The Blue Forest and the Tepees are examples of the Blue Mesa Member of the Chinle Formation of sedimentary rock found in the Park. Sediments of the Blue Mesa Member were deposited by a vast, tropical river system that flowed through this area during the Late Triassic (225 million years ago), similar to what the Amazon River basin looks like today. How do experts know this? Rock color, rock type, stacking patterns, and the fossils they contain give clues to geologists and tell a prolific story about the past environments and how they shifted and changed through time.

The Tepees, examples of rock layers

Brown and yellow sandstone layers were deposited in the river channel, showing where the river flowed through time. Blue and red mudstone layers were laid down in the floodplain. Whitish layers were ash from volcanic eruptions, and are used to determine the exact ages of the rock. Fossilized plants and trees, like horsetails and ferns, indicate a tropical environment. The Tepees, and the adjacent Blue Forest, while located in the middle of the park, expose one of the lowest, and therefore the oldest, rock members within the park.