Petrified wood
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Petrified wood (from the Greek root petro meaning "rock" or "stone"; literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into 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 wood. 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 and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells and as the plant's lignin and cellulose decay, a stone mould forms in its place.
In general, wood takes less than 100 years to petrify. The organic matter needs to become petrified before it decomposes completely.[1] A forest where the wood has petrified becomes known as a Petrified Forest.
Elements
Elements such as manganese, iron and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals take on a yellow, red, and other tint.
Following is a list of contaminating elements and related color hues:
- carbon - black
- cobalt - green/blue
- chromium - green/blue
- copper - green/blue
- iron oxides - red, brown, and yellow
- manganese - pink/orange
- manganese oxides - blackish/yellow
Petrified wood can preserve the original structure of the wood in all its detail, down to the microscopic level. Structures such as tree rings and the various tissues are often observed features.
Petrified wood has a Mohs hardness of 7, the same as quartz crystal.
Petrified wood is the provincial stone of Alberta and also the state gem of Washington.
Locations
- Argentina - The Petrified Forest National Monument in Santa Cruz Province in the Argentine Patagonia has many trees that measure more than 3 m (10 ft) in diameter and 30 m (100 ft) long.[2]
- Australia - Has deposits of petrified and opalised wood. Chinchilla, Queensland is famous for its 'Chinchilla Red'.
- Belgium - Geosite Goudberg near Hoegaarden.[3]
- Brazil - In the geopark of Paleorrota, there is a vast area with petrified trees.[4]
- 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.
- 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 this colorful replaced wood.
- Czech Republic, Nová Paka - The most famous locality on Permian-Carboniferous rocks in the Czech Republic.
- Germany - The museum of natural history in Chemnitz has a collection of petrified trees found in the town in 1737.
- Ecuador - Puyango petrified forest. One of the largest collections of petrified woods in the world.[5]
- Egypt petrified forest in Cairo-Suez road, declared a national protectorate by the minstery of environment, also in the area of New Cairo at the Extension of Nasr city, El Qattamiyya, near El Maadi district, Al Farafra oasis,[6] Al Fayoum depression and actually the entire western desert.[7]
- 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 famous for its petrified woods Thiruvakkarai Village in Chennai, Tamil Nadu. The site is protected by the Geological Survey of India. Petrified woods covers a large area in this site.
- Indonesia- Petrified woods covers several area in Banten and also in some part of Mount Halimun Salak National Park.
- 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:
- Curio Bay on the Catlins coast contains many petrified wood examples.
- Fossil Forest, Takapuna, Auckland, New Zealand
- 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.[8]
- Fossil Forest, Dorset, England
- United States - Some of the better known petrified wood sites include:
- Petrified Wood Park in Lemmon, South Dakota.
- Ginkgo/Wanapum State Park in Washington State.
- Petrified Forest National Park in Arizona.
- Petrified Forest (California) in California.
- Mississippi Petrified Forest in Flora, Mississippi.
- Florissant Fossil Beds National Monument near Florissant, Colorado.
- Yellowstone National Park in Wyoming.
- The south unit of Theodore Roosevelt National Park outside Medora, North Dakota.
- Gilboa Fossil Forest, New York.
- Escalante Petrified Forest State Park in Utah.
- Petrifying Springs in Kenosha, Wisconsin.
Artificial petrified wood
Artificial petrified wood has been produced in a Washington laboratory. In the process small cubes of pine were soaked in an acid bath for two days, then in a silica solution for another two. The product was 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.[9][10] Soaking in a tungsten solution produced a tungsten carbide petrified wood. [citation needed]
See also
- Fossil wood
- Petrified palmwood
- Araucarioxylon arizonicum
- Petrified Forest of Lesbos
- Submerged forest
References
- ^ Petrified Forest National Park - Frequently Asked Questions from the U.S. National Park Service
- ^ http://www.lachlanhunter.deadsetfreestuff.com/JB/Big-Trees/big-trees6.htm
- ^ "A petrified forrest near Hoegaarden".
- ^ Petrified trees and the forest region (Brazil).
- ^ Anon. "The Petrified Forest of Puyango". Viva travel guides. Viva. Retrieved 26 January 2010.
- ^ http://bio.kuleuven.be/sys/iawa/PDF/IAWA%20J%2021-25/24%20(2)%202003/24(2)%20163-172.pdf
- ^ Fossils: The Other Ancient Egypt
- ^ Campbell, J.A. (29 March 1979). "Radiocarbon measurements on submerged forest floating chronologies". Nature. 278 (5703). Nature Publishing Group: 409–413. doi:10.1038/278409a0. Retrieved 12 January 2010.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Petrified Wood in Days, Physorg.com, January 25, 2005 http://www.physorg.com/news2801.html
- ^ Presto! Instant Petrified Wood Created in Lab, Live Science, 27 January 2005 http://www.livescience.com/technology/050127_petrified_wood.html
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