What is Petrified Wood?
Petrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree or tree-like plants having completely transitioned to stone by the process of permineralization. All the organic materials have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue. Unlike other types of fossils which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material.
The petrifaction process occurs underground, when wood becomes buried under sediment or volcanic ash and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the covering material deposits minerals in the plant's cells; as the plant's lignin and cellulose decay, a stone mold forms in its place. The organic matter needs to become petrified before it decomposes completely. A forest where such material has petrified becomes known as a petrified forest.
How Does it Form?
Petrified wood is a fossil in which the organic remains have been replaced by minerals in the slow process of being replaced with stone. This petrification process generally results in a quartz chalcedony mineralization. Special rare conditions must be met in order for the fallen stem to be transformed into fossil wood or petrified wood. In general, the fallen plants get buried in an environment free of oxygen (anaerobic environment), which preserves the original plant structure and general appearance. The other conditions include a regular access to mineral rich water in contact with the tissues, replacing the organic plant structure with inorganic minerals. The end result is petrified wood, a plant, with its original basic structure in place, replaced by stone. Exotic minerals allow the red and green hues that can be seen in rarer specimens.
Where are their Locations?
Areas with a large number of petrified trees include:
Argentina – the Sarmiento Petrified Forest and Jaramillo Petrified Forest in Santa Cruz Province in the Argentine Patagonia have many trees that measure more than 3 m (10 ft) in diameter and 30 m (100 ft) long.
Australia – has deposits of petrified and opalised wood. Chinchilla, Queensland is famous for its 'Chinchilla Red'.
Belgium – Geosite Goudberg near Hoegaarden.
Brazil:
1- Geopark of Paleorrota, there is a vast area with petrified trees.
2- Monumento Natural das Árvores Fossilizadas (Fossil Trees Natural Monument) in Tocantins: petrified forests of dicksoniaceae (specifically Psaronius and Tietea singularis) and arthropitys
3- Petrified forests of dicksoniaceae (specifically Psaronius and Tietea singularis) and arthropitys can also be found in the state of São Paulo
4- Floresta Fóssil de Teresina near Rio Poti, Piauí, Permian (around 280-270 million years ago).
Canada – in the badlands of southern Alberta; Petrified wood is the provincial stone of Alberta. Axel Heiberg Island in Nunavut has a large petrified forest. In and around the North Saskatchewan river, around the Edmonton area.
China – in the Junggar Basin of Xinjiang, northwest China government has issued a crackdown on collecting of this material, but large slabs and even large meeting tables have been made out of the colorful petrified wood.
Czech Republic, Nová Paka – The most famous locality on Permian-Carboniferous rocks in the Czech Republic.
Ecuador – Puyango Petrified Forest (es). One of the largest collections of petrified wood in the world.
Egypt – petrified forest in Cairo-Suez road, declared a national protectorate by the ministry of environment, also in the area of New Cairo at the Extension of Nasr city, El Qattamiyya, near El Maadi district, and Al Farafra oasis.
France – petrified forest in the village of Champclauson
Germany – the museum of natural history in Chemnitz has a collection of petrified trees, from the in situ Chemnitz Petrified Forest, found in the town since 1737.
Greece – Petrified Forest of Lesvos, at the western tip of the island of Lesbos, is possibly the largest of the petrified forests, covering an area of over 150 km² and declared a National Monument in 1985. Large, upright trunks complete with root systems can be found, as well as trunks up to 22 m in length.
India – a geological site known for its petrified wood Thiruvakkarai Village in Chennai, Tamil Nadu. The site is protected by the Geological Survey of India. Petrified wood covers a large area in this site. Petrified Wood has also been discovered in Dholavira in Kutch, Gujarat, dating back to 187-176 million years.
Indonesia – petrified wood covers several area in Banten and also in some part of Mount Halimun Salak National Park.
Palestine – several examples of petrified wood occur in the HaMakhtesh HaGadol in the Negev desert.
Italy:
1-Foresta fossile di Dunarobba, petrified forest near Avigliano Umbro, Umbria (Central Italy), age Piacenzian.
2- Foresta pietrificata di Zuri - Soddì, petrified forest near Soddì (Province of Oristano, Sardinia), age Chattian-Aquitanian.
Libya – Great Sand Sea – Hundreds of square miles of petrified trunks, branches and other debris mixed with Stone Age artifacts
Namibia – petrified forest of Damaraland
New Zealand:
1- Curio Bay on the Catlins coast contains many petrified wood examples.
2- Fossil Forest, Takapuna, Auckland, New Zealand
Saudi Arabia – petrified forest north of Riyadh
Thailand – Bantak Petrified Forest Park in Ban Tak District
Ukraine – petrified araucaria trunks near Druzhkivka
United Kingdom – many examples of petrified submerged forests can be found at low tide around the coast of England and Wales.
1- Fossil Grove, Glasgow, Scotland
2- Fossil Forest, Dorset, England
United States – petrified wood sites include:
1- Petrified Wood Park in Lemmon, South Dakota
2- Ginkgo/Wanapum State Park in Washington State
3- Petrified Forest National Park in Arizona
4- Petrified Forest (California) in California
5- Mississippi Petrified Forest in Flora, Mississippi
6- Florissant Fossil Beds National Monument near Florissant, Colorado
7- Yellowstone Petrified Forest and Gallatin Petrified Forest, Yellowstone National Park, Wyoming
8- The south unit of Theodore Roosevelt National Park outside Medora, North Dakota
9- Gilboa Fossil Forest, New York
10- Escalante Petrified Forest State Park in Utah
11- Agate Desert in the Upper Rogue River Valley near Medford, Oregon
How Long Does It Take for Wood to Petrify?
Wood can be petrified by two basic processes, both of which usually involve burial in volcanic ash. This ash decomposes in the presence of water, enriching the groundwater with silica.
In the first type of petrification, the wood decays in a hot, silica-rich environment. As each molecule of wood decomposes and is carried away, it is replaced by a molecule of silica. Eventually the replacement is complete, with the mineral impurities in the silica being responsible for an array of beautiful colors in the final product. This type of petrified wood can be polished, and often becomes an object of incredible beauty. Once silicification is complete, there is no organic material remaining, but since on occasion the light and dark portions of the tree's growth rings may decay at different rates, hints of the tree rings may be preserved if the minerals present change over time. Many of the petrified trees found in the Petrified "Forest" of Arizona are of this type.
The other type of petrification involves the total infiltration of the porous wood by silica-rich water. The silica (or in a few cases calcite, or a combination of both) plugs up the pores, preventing complete decay. This allows individual cells to be remarkably well preserved, and in many cases the tree ring pattern can easily be seen. The petrified trees in Yellowstone Park are of this type, with tree rings readily visible.
As is now well known, wood can petrify rapidly. Several laboratory experiments have devised ways in which this can be done, mirroring natural settings. (See Sigleo, 1978 "Organic Geochemistry of Silicified Wood," Geochimica et Cosmochimica Acta, vol. 42, pp. 1397-1405, and Leo and Barghoorn, 1976, "Silicification of Wood," Botanical Museum Leaflets, vol. 25, no. 1, Harvard University, 47 pp.)
Wood can also be petrified in field settings. During one field experiment, researchers dangled a block of wood down inside an alkaline spring in Yellowstone Park to see what effect this hot, silica-rich environment would have. In just one year, substantial petrification had occurred. I recently read an advertisement in a magazine for real "hardwood floors." The company was petrifying wood commercially. The point is, it does not take long ages to petrify wood, it just takes the right conditions.
These conditions, with abundant hot waters and rampant volcanism, would be met during the flood of Noah's day and the centuries following.
Artificial petrified wood
Artificial petrified wood has been produced in a Washington laboratory. In the process, small cubes of pine are soaked in an acid bath for two days, then in a silica solution for another two. The product is then cooked at 1400 °C in an argon atmosphere for two hours. The result was silicon carbide ceramic which preserved the intricate cell structure of the wood.
Reference:
Wikipedia: Petrified wood
PETRIFIED WOOD OF SOUTH DAKOTA
John D. Morris, Ph.D. 1995. How Long Does It Take for Wood to Petrify?.