Crater Lake Institute
 

 Home | Site Map | About Us | Donate/Join Us | Contact Us | CLI Store | Press Room

 
 
 You are here: Home > Natural History > Geology > Prominent Geological Features > The Pinnacles

The Pinnacles - Prominent Geological Features of Crater Lake National Park

 
These towering needle-like formations of rock, called fossil fumaroles, projecting from the Sand Creek Canyon floor, were formed under sheets of volcanic pumice that preceded Mazama's collapse.

As the surface of the hot pumice cooled over the years, steam and gases were released by the hot rocks underneath through vents and tubes that were welded into cement hardness by their passage. These ancient vents now stand alone due to the erosion of the surrounding softer materials.

Plate 16. The Pinnacles, Sand Creek canyon, showing pale pumice flow beneath smoke-gray scoria flow, above which lie 10 feet of fine ash. (Photograph by George Grant, National Park Service.) The Geology of Crater Lake National Park, Oregon (1942) by Howell Williams

Note: the numbers associated with each feature name above correspond to their place on the Custom Google Map below

  Related Materials

 

Crater Lake National Park

Prominent Geological Features Map


View Larger Map

 

 

 

 Site Navigation

  Arts

  Crater Lake News

  Cultural History

  Natural History

     Animals

     Climate

     Ecology

     Fungi

     Geology

        Features

        Field Trips

        Geologic History

        Petrology

        Processes

        Soils

     Nature Notes

     Night Sky

     Plants

  Online Library

  Planning a Visit

  Research

 

Current Conditions at Crater Lake National Park

(Image by Grovin Thewer)

 

Crater Lake Webcam