Petrification Jen Cowman

Petrification

• Jen Cowman

• Sakinah Alhabshi

• CEE 367

• Spring 2003

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

Mother Shipton’s Petrifying Well

Background

• Available for public viewing since 1630 – cascades from River Nidd & forms an aqueous curtain to Mother Shipton’s 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

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

Making a Profit?

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

Petrified Forest National Park

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

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

Colors?

• Minerals - iron, manganese, carbon, and chromium, cause the colors of the petrified wood

• Red – iron

• Green – chromium

• Black – carbon / magnetite

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

Liberty Cap

• Liberty Cap

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

Opal Terrace

• Opal Terrace

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

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

“Instant” Petrified Woods

• Advanced Ceramic Labs at the University of Washington, Seattle

• Wood-ceramic composites 20–120% harder than regular wood

• Simple process – soak wood in silicon and aluminium solution, then oven-cure at 44°C (112°F)

• 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

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

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