After The Collapse
Posted by: 
Volcanoguy
N 42° 56.746 W 122° 10.116
10T E 567825 N 4755127
Quick Description: Geologic history sign at Wizard Island Overlook on West Rim Drive.
Location: Oregon, United States
Date Posted: 11/6/2009 3:21:48 PM
Waymark Code: WM7KWR
Views: 0
Long Description:
Marker Name: After The Collapse
Marker Text: About 6,800 years ago, at the climax of a
series of dramatic eruptions, the top of Mt. Mazama collapsed. Left
behind was the huge crater, or caldera, you see today. But before
the caldera filled with water, there were more eruptions.
The most striking evidence of post collapse volcanic activity is
Wizard Island, the small volcano in front of you. Its symmetrical
cone was formed by a fountain of cinders which erupted from the
caldera floor. On the left side of the caldera, a similar cone
appeared, but today it lies hidden 496 feet (151 m) below the lake
surface.
Geologists believe that lava flows which erupted after the collapse
helped to seal the fractured caldera floor, allowing melting snow
and rain to accumulate.
NOTE: This sign uses an age of about 6,800 years ago, while most
other signs abound the park use about 7,700 years ago. This sign
has not been updated to the calibrated age of 7,700 years for the
eruption of Mt. Mazama to form Crater Lake.
Visit Instructions:
Include your thoughts and observations pertaining to this location
and your visit. Provide any additional history that you are aware
of that pertains to this location. If the marker commemorates a
historic building tell us what it is used for now or share with us
the circumstances of an earlier visit to bring this locations
history to life.
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Although visiting this waymark in person is the only thing required
of you to receive credit for your visit, taking the time to add
this information is greatly appreciated.
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