The Grand Canyon is made of all 3 categories of rock:

  1. Igneous Rock - Igneous rocks are crystalline solids which form directly from the cooling of magma.
  2. Sedimentary Rock - Sedimentary rocks are often the result of the accumulation of small pieces broken off of pre-existing rocks.
  3. Metamorphic Rocks - The metamorphics get their name from "meta" (change) and "morph" (form). Any rock can become a metamorphic rock. All that is required is for the rock to be moved into an environment in which the minerals which make up the rock become unstable and out of equilibrium with the new environmental conditions.

For more information on the 3 categories of rock click here.

It will be helpful to know the sequence of the geological strata of the Grand Canyon.

C=cliff
L=ledge
S=slope

Stratum Color Ht.(ft) Age(M yrs) Structure
Kaibab Limestone grayish white 300 250 C
Toroweap Limestone grayish white 200 260 C L
Coconino Sandstone creamy white 300 270 C
Hermit Shale deep red 300 280 S
Supai Group deep red 600 300 C L S
Redwall Limestone gray stained red 600 330 C
Muav Limestone gray with yellow 500 330 C L
Bright Angel Shale blue green 300 540 S
Tapeats Sandstone dark brown 100 550 C L
Vishnu Schist black with mica 1,200 2,000 L S

 

 

 

 

 

 

 


 

The Supergroup, aka The Grand Canyon Series, between the Tapeats and the Vishnu Schist. They are the oldest sedimentry rocks in Canyon.

Stratum Color Ht.(ft) Age(M yrs) Structure
Dox Sandstone red,purple,brown 2,000 >1,100 S
Shinumo Quartzite red,purple,white 1,200 >1,100 C
Hakatai Shale redish orange 800 >1,100 S
Bass Conglonmerate

grayish green

250 >1,100 C L