Petrification

1. Petrification Jen Cowman Sakinah Alhabshi CEE 367 Spring 2003

2. 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

3. Mother Shipton’s Petrifying Well Yorkshire, England

4. 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

5. 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

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

7. 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

8. Petrified Forest National Park Petrified Wood, Arizona

9. 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

10. 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

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

12. 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

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

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

15. Terracette Semicircular ledge formed by travertine that is deposited around slowly rising pools Hot water flows over the lip and forms stalactites New Highland Terrace

16. “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

17. 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

18. 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