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Sunset Crater Visitor Center
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Stop 19 Sunset Crater Visitor Center
Location: Two miles east of Park entrance off US 89.
Date: March 10, 2007

When looking at Sunset Crater one may not notice how complex the formation of this landform was.  Sunset Crater is a result of ancient faulting between Colorado plateau and the basin and range province creating a weak area in the crust. 


Sunset Crater Volcano

 

First, magma and gasses pushed up to Earth’s surface casing pyroclasts, volcanic fragments, to shoot upward along a fissure.  Small cinder cones formed along this fissure before the magma became focused and erupted.  A large cinder cone (Sunset Crater) formed as a shower of cinders and ash piled up around the vent.  At the same time as the cinder cone was forming lava broke out of the side of the cinder cone forming the Bonito Flow.  In some areas the lava pooled and accumulated to nearly 100 ft thick during at least three different flows.  Over the years the oxidation of the iron in the cinders gave sunset crater the unique red color visible today.

Sunset Crater Facts

  • Date of eruption: Between 1040 and 1110 AD
  • Height: 1,000 feet (305 m)
  • Elevation at summit: 8,029 feet (2,447 m)
  • Diameter at base: 1 mile (1.6 km)
  • Diameter at top: 2,250 feet (868 m) from rim to rim
  • Depth of crater: 300 feet (91.4 m)
  • Extruded Material: approximately 1 billion tons
  • Extent of ashfall: approximately 800 square miles (2,072 sq km)

 

 

By W. Patrick Dryer