Chaos Crags

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Chaos Crags
ChaosCrags 8444 45.jpg
Chaos Crags with Chaos Jumbles below.
Elevation 8,503 ft (2,592 m)[1]
Prominence ~ 580 ft (177 m)
Location
Location Lassen Volcanic National Park, Shasta County, California, U.S.
Range Cascade Range
Coordinates 40°31′27″N 121°31′16″W / 40.52417°N 121.52111°W / 40.52417; -121.52111Coordinates: 40°31′27″N 121°31′16″W / 40.52417°N 121.52111°W / 40.52417; -121.52111
Topo map USGS Manzanita Lake
Geology
Type Lava domes[1]
Age of rock Holocene
Volcanic arc Cascade Volcanic Arc[2]
Last eruption 980 CE ± 300 years
Climbing
Easiest route Scrambling

Chaos Crags is the youngest group of lava domes in Lassen Volcanic National Park, California, having been formed as five dacite domes 1,100-1,000 years ago.[3] The cluster of domes is located north of Lassen Peak.

From the base of the crags and extending toward the northwest corner of the park is Chaos Jumbles, a cold rock avalanche which undermined Chaos Crags' northwest slope 300 years ago.[4] Riding on a cushion of compressed air (see sturzstrom), the rock debris traveled at about 100 miles per hour (160 km/h), flattened the forest before it, and dammed Manzanita Creek, forming Manzanita Lake.

In 1974 the National Park Service took the advice of the USGS and closed the visitor center and accommodations at Manzanita Lake. The USGS stated that these buildings would be in the way of a rockslide from Chaos Crags if an earthquake or volcanic eruption occurred in the area.

Chaos Crags and Lassen Peak seen from the side of Manzanita Lake

References[edit]

Further reading[edit]

  • Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle (1997). Geology of National Parks, Fifth edition. Iowa: Kendall/Hunt Publishing. ISBN 0-7872-5353-7. 
  • CVO Description - Lassen Peak (Look under Lassen Volcanic National Park - Points of Interest for info on Chaos Crags in that site)