East side plateau and eroded by tributaries of the Paria River, which is one of the many main tributaries of the upper Colorado before it enters the Grand Canyon Region.
Cedar Breaks National Monument
Zion National Park and
Bruce Canyon National Park
Brightly colored pinnacles, window walls, spires, and pedestals and in horseshoe shaped amphitheaters eroded from the pink cliffs, along the edge of the Paunsaugunt plateau.
The erosional sculptures developed ion the Tertiary Claron Formation
Features: Weathering and erosion of the horizontal beds of Eocene – Claron Formation have produced many interesting shapes in Bryce Canyon.
Stratigraphy of Bryce Canyon National Park
The Claron Formation is divided into the white limestone and pink limestone members. These include pink, red, white, tan, and orange. Thick and thin bedded limestone argillaceous (clay) limestone, Mg-limestone (dolomite), mudstone, conglomerate (gravel), and sandstone. These sediments were deposited in a shallow non-marine lake. The difference in the sediments and the relatively thin beds form the delicate landforms in Bryce Canyon.
Dominated by Claron formation: 3 types: sandstorm, white limestone and pink limestone member
Weathering: breakdown and alteration of material (rock) at earth’s surface
1. Mechanical (physical)
Stresses in/on rock both external and internal
2. Chemical (mineral reactions)
Dissolution: grains +/- cement
Oxidation (removal of electrons)
Rate of weathering depends upon
Particle size: smaller usually faster: more surface area (igneous rocks)
Mineral makeup: minerals that dissolve are removed faster
Climate factors: some rocks are more stable in dry or wet climates
Quartz are resistant to erosion
In dry climate limestone is not dissolved rapidly unlike in florida it dossolves faster because its wetter.
Weathering and erosion carve the rocks through vertical and horizontal cracks steadily widening them. Opening up slot canyons, leaving behind walls or fins
The primary weathering force at Bryce Canyon in frost wedging. The park experience over 200 freeze/thaw cycles each year. In the winter, letting snow in the form of water, seeps into the cracks and refreezes at night. When water freezes it expands by 9%, but by bit, forcing the cracks wider and wider in the same way a pothole in a road.
At the same time this process is converting ridges into fins, it is also forming windows along the perpendicular fractures within individual fins.
Once a window becomes too large to support its own roof it will collapse leaving one leg of the window standing detached- thus creating a hoodoo.
Hard to break rocks when vertically.
Frost activity is an easier way to break down the rock into smaller rocks.
At Bryce Canyon most…