Geologic Features

There are many remarkable geologic features within Crater Lake National Park.  The main forces that created the formations around the park were volcanic activity and glaciers.  The steep walls of the caldera in which Crater Lake rests allow for a clear view of the layers of volcanic ash that built up with multiple eruptions, including the eruption that allowed for the formation of Crater Lake

Cloudcap
Cloudcap offers stunning views of the lake from its pumice covered cliff.  It is similar but older than Llao rock; both are formed of rhyodacite lava that filled an old explosion crater. Cloudcap erupted 20,000 to 30,000 years ago.

Devils Backbone  
This jagged dark rock band runs from the rim down to Crater Lake.  Devils Backbone formed when lava seeped up through a crack in the mountain and cooled.  Over thousands of years, the softer rock around the lava eroded leaving the feature exposed.

Garfield Peak
Named after James Garfield the Secretary of State under Roosevelt and the first cabinet member to visit Crater Lake after it became a national park, Garfield peak provides a spectacular panorama of the lake.  The peak stands at 8,060 feet in elevation and can be accessed by a steep 1.25 mile hike that offers a variety of geologic sights.

Hillman Peak
This peaks is called parasitic cone.  Hillman Peak formed 70,000 years ago.  It was cut in half when Mount Mazama erupted.  The peak is the highest point on the rim.

Kerr Notch and Munson Valley
These two formations are U-shaped valleys.  A valley of this shape indicates that it is carved out by a glacier.  Crater Lake has periodically had glaciers for thousands of years.

Llao Rock

Llao Rock 
This gigantic rock is named after Llao, a Spirit Chief which Klamath tribes said created Crater Lake.  This huge formation is an ancient rhyodacite lava flow which was cut in half when Mt. Mazama erupted 7,700 years ago.  The band-like layers can be seen on the rock; these are formed of lava from different eruptions.  The best view of Llao can be found from the tour boats on the lake.

The Pumice Desert
The Pumice Desert stretches for acres in the northwestern section of the park.  50 feet of pumice and ash settled on the land during the eruption that created the caldera of Crater Lake.  The few plants that can survive on the landscape are hardy and provide food and shelter to many small mammals and insects.

The Pinnacles

The Pinnacles 
These towering formations  of scoria and pumice are found along the sides of the Sand Creek Valley.  The Pinnacles formed when hot volcanic gases shot up through the ash, cementing it.  Through weathering, the softer surrounding materials were carried away, leaving these formations which rise up more than 50 feet. 

Mt. Scott
This peak is called parasitic cone located east of the lake. It is the highest point within the park at 8,926 feet and it is over 400,000 years old.

Sun Notch
Located along the Rim Drive, Sun Notch is a U-shaped, glacier carved valley that is very distinctive.  In August, the sun sets down into the valley of Sun Notch, giving it its name.

The Watchman
The Watchman is a peak on the rim that is a remnant of a lava flow about 50,000 years ago.

Wizard Island and the Merriam Cone 

Wizard Island and Merriam Cone are cinder cones that rose up after the eruption that formed the caldera.  Wizard Island has trees as old as 800 years; it is believed that this is when the Island broke the water's surface.  The Merriam Cone remain below the lake's surface.

 

 

 

 

 

 

 

 

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Crater Lake National Park Trust
PO Box 62
Crater Lake, OR 97604

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