Logging requirements
- Visit the site and let me know the cachers that you are submitting the answers for (if you are in a group together)
- The layers are made up of different composition. What is the largest stone layer that you ovserve?
- Are there stones in all the layers?
- What might the different composition of the layers tell you about the eruptions/debris flows.
- Add a photo of you from the location or of an identifiable item (paper with trackable name). Posting a photo pulled from the internet, or photoshopped will result in instant deletion.
I This area is currently part of the Fremont Indian state park, It is a park dedicated to protecting the cultural heritage of the Fremont Indians that used to live in this area. A museum is the center of the park a few miles to the North East, and contains a number of ancient artifacts and more information about the area.
This area is know as the Marysvale Volcanic Field, it is one of the largest volcanic fields known. It was made up of a large number of volcanoes that were active 32-19 million years ago. These volcanoes produced vast amounts of materials that were thrown and deposited into the surrounding area.
From Jeepstaffs log
Near the end of this period a large volcano erupted 10 miles southwest of this location. So much material was ejected that the volcano collapsed on itself forming the Mount Belnap Caldera.
The lava flows, debris flows, ash falls, and flash floods, and natural erosion that took place, deposited the material into bands that you can see in the rocks to the West.
Following the Mount Belnap eruption the earth here began to be stretched. Erosion carried much of the material into flood plains that filled the areas. Most of the rock around you was most likely carried into the area by erosion. Heavy flows deposited the larger rocks and lighter flows the smaller clay/sandy materials.
Eventually these areas also eroded. The rocky material on top is much harder then the materials underneath. There was not a central river that wore these rocks down. So technically these are not canyons that are being formed. The term head ward erosion is used to describe this type of process. If you take the time to hike over and see the canyon to the west you see a dramatic view of this process. Erosion has cut the sediment deep into the earth forming many small dry slot canyons.
The water from rain erodes away at the rock and sedimentary rocks pulling the rock downward. Because water flows to the lowest part it cuts a deeper and deeper path through the channels.
The sedimentary rock layers themselves are of different harnesses, and wear at different rates. As the stone wears you get hoodoos left behind. A hoodoo is a tall spire of rock that extends upwards. Usually topped by harder rocks, or rock layers that protect the ‘cap’ from eroding. A hoodoo has variable thickness; some thin parts will get thicker as you go up and reach a harder layer of sediment/rock..