Christian Sedona - the Volcanic Tour!

Geology:
Northern Arizona!

VOLCANIC TOUR! Northern Arizona is a geological wonderland and worth a week just to explore it!! It's on the southwest edge of the Colorado Plateau, and displays so many of the various geological layers, the best OF COURSE being near Sedona! CLIK on each location to see more information.

NR North Rim. Of the Grand Canyon. Sits on Kaibab limestone and above the South Rim elevation. The Colorado River cut through the uplift (one of many theories!), creating the canyon.
CP Coconino Plateau. Covered with thick limestone, which protects the softer layers below (which the Colorado River cut through north of here).
SG Seligman Area. Just west of Seligman are the Aubry Cliffs and the western edge of the Colorado Plateau.
SF San Francisco Peaks area. As the tectonic plate moved west over a likely hot spot, volcanos erupted west to east, with Sunset the youngest.

EC Echo Cliffs. On US89 going north on the right, forced roads in a north-south orientation.
MV Monument Valley. Gorgeous sandstone monuments as well as volcanic necks further south.
BM Black Mesa. Actually located further north-east, source of crataceous coal for smoky electric plants near Page.
CA Cameron area. Beautiful sculpted formations from the Chinle mudstone.
PD Painted Desert. Gorgeous colored layers from the Chinle and Moencopi.
I-17 Forests. Volcanic flows overtop the Kaibab limestone.

Northern Arizona is actually fairly young ... at least the parts that you notice as 'wow!': the Grand Canyon, San Francisco Peaks, Painted Desert and Petrified Forest. Even the meteorite crater off of I-40 is a fairly recent decision concerning its origin. What is not so obvious is that a good portion of northern Arizona is actually missing! Basically you draw a line at the Kaibab formation and then imagine the rest above it. Presumably it eroded away. To see 'the rest', you just keep driving further and further north. Now 'that' is some erosion!

I think most people would say the Grand Canyon is the most impressive. True, it's deep. But it's only impressive because almost nothing happened there! Only as you get to the bottom of the canyon do you see any major geologic change. The rest is an uplift(?) and an agreesive LITTLE river! For contrast, visit Jerome and imagine that you're on the bottom of the ocean. Now THAT is twisted!

ADDITIONAL NOTES

I-17 I-17 FORESTS. This whole area is permian kaibab limestone covered with recent volcanic flows, all the way south to the mogollon rim and the Verde Valley. The forest is ponderosa pine and is the largest stand in the world, stretching from eastern New Mexico to west of the San Francisco peaks. As the railroads moved west in the late 1800s, it was these forest that provided both cross ties and fuel. When forest reserves were created in the early 1900s, much of this area had been cut-over. If you visit Riordan State Park in Flagstaff, they were your main culprits!

BM BLACK MESA. If you're driving north toward Kayenta, it'll be on your right. After Red Lake, you'll notice a railroad on your left. They mine coal and ship it to a plant near Page. They also slurry the coal to another plant over in Nevada, pumping the water out of the aquafer. It's this latter part that concerns many Hopi and Navajo. The upper mesa has many of the layers you'll only run into further to the northeast in Colorado ... Mancos shale and Mesa Verde sandstone. It's the latter, that was a shoreline that produced the coal.

CA CAMERON AREA There's an interesting trading post on the south side of the Little Colorado on US89. The old bridge is also preserved. If you look east, that's the Chinle and towards Flagstaff the Moencopi. The latter contains amphibian remains, plus visible wave-marks from the triassic mud flats. At Cameron, the Little Colorado begins cutting deeply into the Kaibab limestone. If you drive towards the Grand Canyon, there's a couple of places you can stop near the edge of the Little Colorado, and walk down to view the canyon cuts. Going north from Cameron, the eroded Chinle towards the east is fun to play on, running up and down the sides.

CP COCONINO PLATEAU. This is all ocean-bottom kaibab limestone, sitting overtop old desert-driven sand dunes (Coconino sandstone). As you drive towards the Grand Canyon, imagine yourself deep underneath the sea just north of the equator. You can see millions of sponges all around you. It's their silica needles that you are driving on! Unbeknownst to them, the earth is about to heat up. It will get so hot, that it will kill 99% of the species on the earth. Lucky for you, you're underwater! Yep, you're nearing the end of the Permian and the big die-off.

EC ECHO CLIFFS. As you can well imagine, the name came from spanish explorers on the other side of the Colorado (don't know if true!). Echo Cliffs begin on the east side of US89 just north of Tuba City and continue north connecting up with the Paria river cliffs near Page. If you pass the little town of the 'the Gap', that's the only natural cut, for the Navajo into the interior on the other side. The cliffs themselves are topped off with thick Navajo sandstone from the Glen Canyon group. Beneath, forming the lower massive facing, is the Wingate sandstone. It sits on top of the Chinle, which 'spreads out' toward the highway. This is the layer matching the age of dinosaurs. So, drive careful, especially at night when the dinosaurs are most prevalent. Ha.

MV MONUMENT VALLEY. This is just north of Kayenta, and crossing over to the Utah side on US163. Going north from Kayenta, you essentially 'cut' through the teeth of the Comb Ridge monocline, which is topped with the salmon colored Navajo sandstone. Then, as you drive further north, you begin 'dropping' through the geologic layers even though you're moving UP the Monument uplift. By the time you get to the beautiful cliffs, you're looking at the rounded jurassic Navajo sandstone, over top the sharper Wingate sandstone, both forming the monuments. The base is the multi-hued triassic Chinle that combines with the blue sky, to create such a beautiful palette!

NR NORTH RIM - GRAND CANYON. This is part of the Kaibab upwarp and is the 'high side' of the canyon. If you look at a map towards the east, you'll notice the river is going south at a fairly good clip, and then makes a hard-right for several hundred miles, only to cut due south again over by California. Why? If you read early theories, they assumed the river kept going south into the Little Colorado drainage, with another river cutting its backside north. Eventually the two met where the Little Colorado enters the Colorado. Another theory places the river rounding a slight uplift that later became a BIG uplift. A more recent theory sees just the opposite ... the western portion DROPPING, thus creating the cutting of the Colorado river. What amazes me is the actual geologic layers ... for millions of years, they're almost exactly flat. All the way down to the Shinumo in the pre-cambrian. Now THAT is a VERY stable geological period of time!

If it looks a lot like Sedona, that's because it's almost the same series with the Kaibab on top, then the Toroweap, Coconino sandstone, Hermit shale and finally down to the Redwall limestone. That would be Sedona!

PD PAINTED DESERT / PETRIFIED FOREST. The famous petrified logs are from the triassic chinle formation. Most of the logs are battered, so it is assumed they were floating in flooded streams; all are horizontal when covered by the sand. It was the volcanic ash in the chinle that provided the silica in the petrification process. The whole area here was a flood plain with very large trees.

'Painted desert', which is on the north side of the interstate, is the triassic chinle formation containing mudstone and volcanic ash which creates clay 'bentonite' which puffs when it gets wet ... thus is soft and colored surface.

Going west from the national park, you drop to the triassic moencopi sandstone/siltstone (dinosaurs), and then looking southwest from Holbrook, you'll see the permian Coconino sandstone topped with the permian kaibab limestone. Looking northerly, you'll see what is believed to be the drainage of the ancient Colorado river, into 'Bidahochi Lake' and the Bidahochi formation topping the buttes in Pliocene times.

SF SAN FRANCISCO PEAKS AREA. Did you know the name of these mountains is OLDER than the city of San Francisco? True. But the various volcanos in this area are geologically young. If you're driving east from Kingman, you hit your first volcano on the east side of Williams at 4mya. Driving further you pass Sitgreaves at 2.5mya and Kendricks at 2mya. The large San Fransisco Peaks began about 2.8mya and the volcanos in east Flagstaff are just .2mya. The prettiest, Sunset Crater is only 1,000 years ago!

The theory is that the tectonic plate is slowly moving west over a hot spot deep in the earth. So, the successive eruptions from west to east track the movement.

The peaks themselves are 'strato-volcanic', and are currently almost 13,000 ft high, the highest in Arizona. The theory is that the volcano used to be about 16-18,000 ft high, but 'blew up' similar to Mt St Helens. Glaciers later smoothed out the shape. If you're familiar with volcanos, this type with a 'high-angle' comes from thick lava closer to the surface of the earth. Flatter volcanos have lava that is more liquid and thus not as high.

If you visit Sunset Crater and Wapatki National Monument east of Flagstaff, you'll find it quite interesting. The native-american ruins on the north were built following the eruptions and thus illustrate just how 'recent' the whole area is.

SG SELIGMAN AREA. If you're a Route 66 lover, old 66 turns toward Peach Springs at Seligman, following the Aubrey Cliffs and out onto the Redwall limestone. Further west where 66 dips south, are the Grand Wash cliffs, which track northward transitioning into the Hurricane cliffs. All of these track the western edge of the Colorado Plateau. A really nice drive is further north in Utah, where the stair-stepped layers are even more visable.