Petrification

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Petrification

• Jen Cowman
• Sakinah Alhabshi
• CEE 367
• Spring 2003

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What is Petrification?

• The replacement of the normal cells of organic
  matter with other minerals
• According to evolutionary doctrine, petrification
  requires much time, usually millions of years,
  but how much time is really needed in this
  process?
• Things are usually petrified in soil or by a
  water source with a high mineral content
• Affected by temperature, pressure, minerals

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Mother Shiptons Petrifying Well
Yorkshire, England
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Background

• Available for public viewing since 1630
  cascades from River Nidd forms an aqueous
  curtain to Mother Shiptons Cave
• High mineral content
• calcium, sodium and magnesium
• traces of lead, zinc, iron, manganese and
  aluminium
• Exist mainly as sulphates and carbonates, with
  some chlorides and a trace of silica
• Proportions have remained more or less regular
  over many years

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Facts

• As dissolved calcite (CaCO3) is exposed to air,
  CO2 escapes and the limestone is deposited
• 2HCO3- Ca2 ? CO2(g) CaCO3(s) H2O
• Petrifies sponges/teddy-bears 4-6 months,
  Animals 12-18 months
• Flow of 700 gal/hr

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Making a Profit?
Souvenirs undergoing petrification to be sold to
tourists basket, teddy-bears, sponges, books,
gloves, foxes, cats, dogs, birds, and boots
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Effects

• Tufa soft rock
• Travertine hard rock
• Dark/light bands
• The face of the rock has to be scoured every 6
  weeks to prevent it from getting top heavy and
  falling over

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Petrified Forest National Park
Petrified Wood, Arizona
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Requirements

• The dead wood needs to be protected from decay
• The dead wood becomes saturated with
  mineral-laden water
• The porous nature of wood allows the movement of
  water-borne particles
• The water itself needs to harbor specific
  minerals necessary for petrification

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How?

• After burial and saturation, chemical reactions
  take place between the minerals and the cellulose
  compounds in the cell walls
• Mineral crystals grow in the spaces left behind
  by the dissolution of the cell walls
• Two phases of crystal deposition result in
  complete mineral replacement of the wood

Cross-section, cell walls infiltrated by quartz. 
X350
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Colors?

• Minerals - iron, manganese, carbon, and chromium,
  cause the colors of the petrified wood
• Red iron
• Green chromium
• Black carbon / magnetite

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Yellowstone National Park

• Continental hot spot in Wyoming
• Mammoth Hot Spring Terraces
• 100 hot springs scattered over terraces
• Thermal springs deposit CaCO3 as travertine
  between 2.8 56.5 cm/year
• Silica deposition rates into blocks of wood in
  alkaline springs at Yellowstone between 0.1 and
  4.0 mm/yr

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Liberty Cap

• Liberty Cap
• 45 ft tall
• Cone formed from a steady flow of hot water from
  a single source
• Presently inactive

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Opal Terrace

• Opal Terrace
• 160 F
• Known for its pastel colors
• A tennis court had to be removed because it grew
  too quickly

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New Highland Terrace

• Terracette
• Semicircular ledge formed by travertine that is
  deposited around slowly rising pools
• Hot water flows over the lip and forms stalactites

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Instant Petrified Woods

• Advanced Ceramic Labs at the University of
  Washington, Seattle
• Wood-ceramic composites 20120 harder than
  regular wood
• Simple process soak wood in silicon and
  aluminium solution, then oven-cure at 44C
  (112F)
• Hamilton Hicks, Connecticut made a chemical
  'cocktail' of sodium silicate, natural spring or
  volcanic mineral water - high content of
  calcium, magnesium, manganese and other metal
  salts, and citric or malic acid

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Potential Uses for Instant Petrified Woods

• Fireproofing wooden structure
• Longer-wearing floors and furniture
• Greater strength wood
• Insect, decay and salt-water proof wood in
  buildings

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Conclusions

• Misconception fossilized wood buried in rock
  strata must have taken thousands, if not
  millions, of years to petrify
• Can be rapid
• Good knowledge base we can make petrified wood
  for our benefit