Geology of the National Parks Through Pictures - Sunset Crater

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You can find more Geology of the National Parks Through Pictures as well as my Geological State Symbols Across America series at my website Dinojim.com.

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Sunset Crater Volcano National Monument

View of the entrance sign with the volcano in the background.



The Sunset Crater Volcano is a volcano that last erupted about 1,000 years ago. It is a type of volcano known as a cinder cone, meaning that its eruptive material is small darkly colored rocks that pile up around the central vent. These rocks are typically a type of rock known as scoria, a vesicular (has lots of air holes in it), mafic (dark), volcanic rock. Since the last eruption was within the last 10,000 years, this volcano is still considered active by volcanologists.

Along with the cinder cone, there are also lots of lava flows within the park. Here you can see a lava flow that still looks as fresh as if it were a few years old. Since the desert environment does not get much rain, the volcanic rocks have a tendency to take a long time to break down, leaving these features for thousands of years.

Sunset Crater Volcano is part of a fissure eruption, which is a long crack in the ground that erupts like a volcano. Here the fissure runs along the left part of the photo ending at Sunset Crater Volcano in the middle of the photo.

Sunset Crater Volcano isn't the only volcano within the area or even within the park. There are lots of volcanos in this part of Arizona, mostly due to the plate tectonics of the area (as described in the Grand Canyon NP section above). The thinning of the crust due to the uplift of the plate causes weak spots in the crust where volcanic material can easily break through. 

Geological Quote of the Week - Bird Frisbee

This quote is from a book about evolutionary convergence.

"Continuing work has shown that the resolution of oilbirds' echolocation is rather crude, at least when it comes to avoiding discs deliberately suspended in their flight path."

This just makes me think of scientists throwing disks at birds and watching them crash.


Morris, S.C., 2003, Life's Solution: Inevitable Humans in a Lonely Universe: Cambridge, Cambridge University Press.


And as always you can check out my other Geological Quotes at my website HERE.

Geology of the National Parks Through Pictures - Walnut Canyon

My next post about the Geology of the National Parks Through Pictures is...

You can find more Geology of the National Parks Through Pictures as well as my Geological State Symbols Across America series at my website Dinojim.com.

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Walnut Canyon National Monument

Walnut Canyon is a archaeological site located within a geological site. The canyon itself is made up of several Colorado Plateau rock units that were impacted, like several other National Parks in the area, by the uplift of the Colorado Plateau. The canyon is capped with the Permian Kaibab Formation limestone, forming a layer resistant to erosion. The shelters created within the rocks are located within a shale and siltstone layer of the Kaibab Formation beneath this limestone roof. 

Below the Kaibab Formation is the Coconino Sandstone and Toroweap Formation. These rock units are often difficult to differentiate from each other so they tend to blend together within the park.

Here you can see a view of the canyon with the alternating hard and soft rock formation.

View of the cliff dwellings built into the carved out section of the rocks.

Some more cliff dwellings.

And more cliff dwellings with a more complete wall located on the other side of the creek meander.

Following the trail around the houses, the trail goes back up the canyon.

Here is the Coconino Sandstone which underlies the Kaibab Formation. The cross-bedding is characteristic of the unit and illustrates the former desert dune history of the rock units. 

A view of Walnut Creek, which carved out the canyon through the rock units. The cliff dwellings are located within the meander on the right side of the photo.

CBS Sunday Morning - Professional Paleontologists are Starting Early

So here was a nice story on CBS Sunday Morning this past Sunday about a kid who wanted to be a professional paleontologist so bad that he applied for the position of curator at the Denver Museum of Nature and Science when Kirk Johnson left. The position was stolen from the poor kid by Scott Sampson but there was a happy ending in it all.

The video can also be found at http://www.cbsnews.com/video/watch/?id=50143923n