Monday, May 28, 2012

May 20, 2012. Vermillion Cliffs.

We're driving from Cedar City, Utah, to Tuba City, Arizona.
Enjoy the Vermillion Cliffs.

But first, a geology lesson
about the Grand Staircase.

The Grand Staircase refers to an immense sequence of sedimentary rock layers that stretch north
from the Grand Canyon, through Zion National Park, and into Bryce Canyon National Park.
In the 1870s, geologist Clarence Dutton conceptualized this region as a huge stairway ascending out of the bottom of the Grand Canyon northward,
 with the cliff edge of each layer forming giant steps. 

Edges exposed by uplift are susceptible to erosion.
 In Utah, the southern edges of the High Plateaus
have eroded into the cliffs of the Grand Staircase.

  • A Grand Canyon
  • B Chocolate Cliffs
  • C Vermillion Cliffs
  • D White Cliffs
  • E Zion Canyon
  • F Gray Cliff
  • G Pink Cliffs
  • H Bryce Canyon

Deformation, Uplift, and the Grand Staircase
Horizontal compression related to the formation of the Rocky Mountains deformed these rocks.  Then volcanic materials from the north and west covered part of the region:  black rocks at the mouth of nearby Red Canyon and on the Sevier Plateau - to the north -  still protect the softer underlying layers.  About 10 million years ago, the Earth pulled apart, moving and tilting great blocks along north-south trending fault lines.  Layers that were once connected then became displaced vertically by several thousand feet,
 thereby forming the High Plateaus of Utah.

Older Cretaceous layers now rested side by side with younger Tertiary layers across the fault lines.  Streams began to remove the sediments that had been deposited by their ancestors.  Working on the weakened edges of the upthrown blocks, water gradually removed the uppermost Tertiary layers and exposed the Cretaceous rocks once again.  At that point these drab marine sediments lay on the surface of the land side by side with the brightly colored rock formed from the deposits of freshwater lakes and streams.


Researching the Cliffs,
I just read that Huff Post had a recent article
on the Vermillion Cliffs -
about National Geographic's February article
about the Vermillion Cliffs.

Enjoy my pictures.

We're looking at millions of years of work here.

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