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Mitchell Caverns

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Mitchell Caverns Presentation Transcript

  • 1. Mitchell Caverns Wonder of the Mojave Desert
  • 2. Providence Mountains State Recreation Area
    • 100 mi east of Barstow; 60 mi west of Needles
    • Contains 20 known caves, including Mitchell Caverns
    • 5,900 acres in eastern Mojave Desert
    • elevation range: 3,400 - 7,171 ft
  • 3. Mitchell Caverns
    • Located at Park headquarters
    • 4,300 ft with view of surrounding land
    • Dimensions
      • 300 ft below surface
      • several hundred ft long
    • 65° year round
    • Only limestone caves in the CA park system
    • Electrically lit, paved walkways
  • 4. The Caverns
    • 2 caverns may have been continuous but filled in by calcite deposits
    • Passage created in early 70s
    • Winding Stair Cave also included in park
      • Used for practice cave rescues
    • El Pakiva
      • ‘ house of the devil’ or ‘pool of water from the eye of the mountain’
    • Tecopa
      • Legendary Shoshone chief
  • 5. What’s the difference between a cave and a cavern , anyway?
    • According to the National Park Service, not much:
    • Cave: An underground chamber or cavity created by natural means.
    • Cavern: A large cave or a cave of indefinite extent. Considered by some cave geologists as caves formed by solution.
  • 6. Geologic History
  • 7. Formation of Caverns
    • About 12 Ma:
      • Area had wetter climate; rainforest
      • Organic groundcover makes rainwater acidic
      • Carbonic acid seeps through ground; dissolves limestone
    • Climate change
      • Water table lowers
      • Environment for creating speleothems
      • Calcite-rich water precipitates when caverns are not water filled
  • 8. Rare and Exciting Speleothems
    • Coral Pipes
      • small, cylindrical formations
      • pebbles allow for erosion into silt pillars
      • pipes created when travertine deposits on silt pillars
      • only found in 8 caves worldwide
      • rare because flow of water must cease at critical point
    • Cave Shields
      • 3 ft wide, 1/2 in thick, semicircular sheet of calcite
      • formed when water seeping in from a crack in the walls deposits layers of calcite
      • only found in 60 caves in the US
  • 9. Fairly Nifty Speleothems
    • Flowstone (travertine): formed by flowing water.
    Cave coral (popcorn): knobby clusters of calcite or aragonite Stalagmites: formed up from the floor, generally beneath a stalactite. Helictites: deposit that generally spirals as it grows, seems to defy gravity. Stalactites: formed on ceilings.
  • 10. Wanted: Dead or Alive
    • Probably last growing significantly at the end of the last Ice Age (10,000 yrs ago)
    • Long thought to be ‘dead’
    • Currently active only during heavy rains
    • ‘ Normal’ growth rate: 1 inch/20 yrs
    • Mitchell growth rate: 1 inch/10,000 yrs
  • 11. Cave Life
    • Townsend’s bats
      • relocated after installed passage created airflow changes
      • after airlock put in, started to return
    • Rare spider beetle
    • Prehistoric Ground Sloth
      • 15,000 yrs old; from Pleistocene time
      • also fossilized tissue of giant redwoods, tropical ferns from this time
  • 12. Chemehuevi Indians
    • 500 years
    • ‘ Eyes of the mountain’
    • Evidence
      • cavern walls blackened by smoke
      • pottery shards, arrowheads, hidden food and tool caches found
    • Thought to be used seasonally for shelter and storage
    • ‘ young boys were probably left in the darkness of the caves as part of a coming-of-age ritual’; ‘came to harvest pinyon nuts in a five-year nomadic cycle’
    • Way of life changed with introduction of miners, explorers, etc.
    • Currently live on reservation by Colorado River
  • 13. Crystal Cave and Ghost Stories
    • Jack and Ida Mitchell
    • Moved to desert
      • Early 1930s
      • Came because of Depression
    • Decided to develop caverns commercially
      • Prospecting silver not profitable
    • Improvements to area
      • Stone buildings, including current park headquarters
      • Built 23 mi road to caverns
    • Explored caverns; stuck in Winding Stair Cave for 2 days
    • Gave tours of the caverns
      • Known for candle lit tours; ghost stories
  • 14. Birth of a Park
    • Park transferred to state 1954
    • Kept a state entity according to CA Desert Protection Act of 1994
    • By 1950s, Mitchell could no longer care for caverns
    • Entered negotiations with CA
    • Died before negotiations complete
  • 15. Oliver Stone and Mitchell Caverns?
    • Scene from 1991 film “The Doors” shot in the caverns
    • Controversy over pictographs added to walls
      • Couldn’t be removed at first
      • Hired special team to flush paint out of walls
    • Initiated more interest in the caverns
    • Other recent events:
      • Earthquake in October 1999 temporarily destabilized roof/trail
      • Reopened 2000
  • 16.