Petrified wood

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Polished slice of a petrified tree from the Late Triassic Epoch (approximately 230 million years ago) found in Arizona. The remains of insects can be detected in an enlarged image. Polished slice of petrified wood.jpg
Polished slice of a petrified tree from the Late Triassic Epoch (approximately 230 million years ago) found in Arizona. The remains of insects can be detected in an enlarged image.
Petrified log at the Petrified Forest National Park PetrifiedWood.jpg
Petrified log at the Petrified Forest National Park

Petrified wood (from the Latin 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. Petrifaction is the result of a tree or tree-like plants having been replaced by stone via a mineralization process that often includes permineralization and replacement. [1] The organic materials making up cell walls have been replicated with minerals (mostly a silicate, such as opal, chalcedony, or quartz). In some instances, the original structure of the stem tissue may be partially retained. Unlike other plant 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 in water-saturated sediment or volcanic ash. The presence of water reduces the availability of oxygen which inhibits aerobic decomposition by bacteria and fungi. Mineral-laden water flowing through the sediments may lead to permineralization, which occurs when minerals precipitate out of solution filling the interiors of cells and other empty spaces. During replacement, the plant's cell walls act as a template for mineralization. [2] There needs to be a balance between the decay of cellulose and lignin and mineral templating for cellular detail to be preserved with fidelity. Most of the organic matter often decomposes, however some of the lignin may remain. [3] Silica in the form of Opal-A, can encrust and permeate wood relatively quickly in hot spring environments. [4] However, petrified wood is most commonly associated with trees that were buried in fine grained sediments of deltas and floodplains or volcanic lahars and ash beds. [5] [6] A forest where such material has petrified becomes known as a petrified forest.


The outline of cells visible in a segment of petrified wood Polished petrified wood cells.jpg
The outline of cells visible in a segment of petrified wood

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, or another tint.

Following is a list of contaminating elements and related color hues: [7] [8]

Petrified wood can preserve the original structure of the stem in all its detail, down to the microscopic level. Structures such as tree rings and the various tissues are often observed features.

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 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.


Following the Great Depression in the 1930s, people began flocking to the mountains and deserts hoping to discover any sort of rock, stone or gem that could be turned into jewelry as a source of income. An assortment of rock was discovered which included petrified woods. "Rockhounding", as hobbyists would call it, became very popular. Many rock clubs began to establish throughout the United States. Soon after collectors started setting up rock shops where they were able to sell their merchandise to the public. As years went by rockhounders would perfect their craft at making jewelry using all sorts of different techniques, equipment, and molds. Having experience with their craft, first-generation rockhounders would soon teach fellow amateurs their skills. [9]


Areas with a large number of petrified trees include:


Chunk of petrified wood near El Kurru (Northern Sudan) ElKurruPetrified Wood.jpg
Chunk of petrified wood near El Kurru (Northern Sudan)
Petrified log and Welwitschia at Namibia Petrified forest Petrified tree trunk and Welwitschia (Namibia).jpg
Petrified log and Welwitschia at Namibia Petrified forest




North America

Petrified logs at Petrified Forest National Park, Arizona, USA Petrified Forest National Park Wood.jpg
Petrified logs at Petrified Forest National Park, Arizona, USA

South America

Petrified log in Paleorrota geopark, Brazil Parque paleobotanico de Mata..JPG
Petrified log in Paleorrota geopark, Brazil
Puyango petrified forest, Ecuador Puyango fossil tree 02.JPG
Puyango petrified forest, Ecuador

See also

Related Research Articles

Fossil Preserved remains or traces of organisms from a past geological age

A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants. The totality of fossils is known as the fossil record.

Petrified Forest National Park National park of the United States

Petrified Forest National Park is an American national park in Navajo and Apache counties in northeastern Arizona. Named for its large deposits of petrified wood, the fee (chargeable) area of the park covers about 230 square miles, encompassing semi-desert shrub steppe as well as highly eroded and colorful badlands. The park's headquarters is about 26 miles (42 km) east of Holbrook along Interstate 40 (I-40), which parallels the BNSF Railway's Southern Transcon, the Puerco River, and historic U.S. Route 66, all crossing the park roughly east–west. The site, the northern part of which extends into the Painted Desert, was declared a national monument in 1906 and a national park in 1962. The park received 644,922 recreational visitors in 2018. Typical visitor activities include sightseeing, photography, hiking, and backpacking.

Florissant Fossil Beds National Monument national monument in the United States

The Florissant Fossil Beds National Monument is a national monument located in Teller County, Colorado. The location is famous for the abundant and exceptionally preserved insect and plant fossils that are found in the mudstones and shales of the Florissant Formation. Based on argon radiometric dating, the formation is Eocene in age and has been interpreted as a lake environment. The fossils have been preserved because of the interaction of the volcanic ash from the nearby Thirtynine Mile volcanic field with diatoms in the lake, causing an diatom bloom. As the diatoms fell to the bottom of the lake, any plants or animals that had recently died were preserved by the diatom falls. Fine layers of clays and muds interspersed with layers of ash form "paper shales" holding beautifully-preserved fossils.

Petrifaction The process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with mineral

In geology, petrifaction or petrification is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals. Petrified wood typifies this process, but all organisms, from bacteria to vertebrates, can become petrified. Petrifaction takes place through a combination of two similar processes: permineralization and replacement. These processes create replicas of the original specimen that are similar down to the microscopic level.

Polystrate fossil Creationist term for a fossil that extends through more than one geological stratum

A polystrate fossil is a fossil of a single organism that extends through more than one geological stratum. This term is typically applied to "fossil forests" of upright fossil tree trunks and stumps that have been found worldwide, i.e. in the Eastern United States, Eastern Canada, England, France, Germany, and Australia, typically associated with coal-bearing strata. Within Carboniferous coal-bearing strata, it is also very common to find what are called Stigmaria within the same stratum. Stigmaria are completely absent in post-Carboniferous strata, which contain either coal, polystrate trees, or both. The word polystrate is not a standard geological term. This term is typically found in creationist publications.

<i>Araucarioxylon arizonicum</i> species of plant

Araucarioxylon arizonicum is an extinct species of conifer that is the state fossil of Arizona. The species is known from massive tree trunks that weather out of the Chinle Formation in desert badlands of northern Arizona and adjacent New Mexico and Chemnitz petrified forest in Chemnitz, Germany, most notably in the 378.51 square kilometres Petrified Forest National Park. There, these trunks are locally so abundant that they have been used as building materials.

Ginkgo Petrified Forest State Park Recreational area and geologic preserve in Vantage, Washington, USA.

Ginkgo Petrified Forest State Park/Wanapum Recreational Area is a geologic preserve and public recreation area covering 7,124-acre (2,883 ha) on the western shoreline of the Columbia River's Wanapum Reservoir at Vantage, Washington. Petrified wood was discovered in the region in the early 1930s, which led to creation of the state park as a national historic preserve. Over 50 species are found petrified at the site, including ginkgo, sweetgum, redwood, Douglas fir, walnut, spruce, elm, maple, horse chestnut, cottonwood, magnolia, madrone, sassafras, yew, and witch hazel.

Fossil wood wood that is preserved in the fossil record

Fossil wood is wood that is preserved in the fossil record. Over time the wood will usually be the part of a plant that is best preserved. Fossil wood may or may not be petrified. The study of fossil wood is sometimes called palaeoxylology, with a "palaeoxylologist" somebody who studies fossil wood.

Gallatin Range mountain range

The Gallatin Range is a mountain range of the Rocky Mountains, located in the U.S. states of Montana and Wyoming. It includes more than 10 mountains over 10,000 feet (3,000 m). The highest peak in the range is Electric Peak at 10,969 feet (3,343 m).

National Fossil Wood Park, Tiruvakkarai

The National Fossil Wood Park, Tiruvakkarai is a notified National Geo-heritage Monument located in the Villupuram District in the Indian state of Tamil Nadu and is maintained by the Geological Survey of India. The park was established in 1940 and is located 1 km east of Thiruvakkarai village on the road between Tindivanam and Pondicherry.

Permineralization Type of fossilization

Permineralization is a process of fossilization in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineralization is particularly useful in studies of the internal structures of organisms, usually of plants.

Specimen Ridge mountain in United States of America

Specimen Ridge, el. 8,379 feet (2,554 m) is an approximately 8.5-mile (13.7 km) ridge along the south rim of the Lamar Valley in Yellowstone National Park. The ridge separates the Lamar Valley from Mirror Plateau. The ridge is oriented northwest to southeast from the Tower Junction area to Amethyst Mountain. The ridge is known for its abundance of amethyst, opal and petrified wood. It was referred to as Specimen Mountain by local miners and was probably named by prospectors well before 1870. The south side of the ridge is traversed by the 18.8-mile (30.3 km) Specimen Ridge Trail between Tower Junction and Soda Butte Creek. The trail passes through the Petrified Forest and over the summit of Amethyst Mountain el. 9,614 feet (2,930 m).

Chemnitz petrified forest

The Chemnitz petrified forest is a petrified forest in Chemnitz, Germany.

Amethyst Mountain, el. 9,609 feet (2,929 m) is the highest peak and central part of a northwest – southeast trending ridge that lies between the Lamar River to the northeast and Deep Creek to the southwest within Park County, Wyoming. From northwest to southeast, this ridge consists of Specimen Ridge, Amethyst Mountain, and the Mirror Plateau in Yellowstone National Park. The nearest town is Silver Gate, Montana, which is 19.2 miles away.

<i>Tietea singularis</i> species of plant

Tietea singularis was a Marattialean tree fern from the Late Carboniferous to Permian which grew up to 12 metres (39 ft) in height. It is estimated to represent close to 90% of some fossil assemblages in Brazil.

Petrified forest, Khorixas Nambian national forest

The Petrified forest, located 42 kilometres (26 mi) west of the Namibian town of Khorixas, on the C39 road, is a deposit of large tree trunks that have "turned to stone" through a process of diagenesis. There are at least two large tree trunks, each 45 metres (148 ft) long, exposed to view. Several hundred others are located in the vicinity.

Bosques Petrificados de Jaramillo National Park national park in Argentina

The Jaramillo Petrified Forest National Park is a protected area of petrified forest located in the Deseado Department, in the northeast of Santa Cruz Province, Argentina. Formerly part of the site was a natural monument, established in 1954 and known as the Petrified Forest Natural Monument, covering about 13,700 hectares. This area has remnants of a forest preserved in stone, that had been growing on the site before the upthrust of the Andes some 150 million years ago. In December 2012, further land was added and the protected area was reclassified as a national park with a total area of 78,543 hectares.

Puyango Petrified Forest

Puyango Petrified Forest is a fossil deposit of petrified wood located in the middle basin of the Puyango River, between the Ecuadorian provinces of El Oro and Loja. The area covers 2,658 hectares and its sediments are divided into four geological formations, dating from the late Cretaceous period. These deposits are rich in both fossilized trunks and leaves - which belonged to the typical Mesozoic flora - as well as fossils of invertebrates such as bivalves, ammonites, echinoderms, among others.

Akal Wood Fossil Park

Akal Wood Fossil Park is a National Geological Monument of India located in Jaisalmer district, Rajasthan. It is also a Biodiversity Heritage Site.


Arthropitys is an extinct genus of calamitacean equisetale. The petrified fossils of Arthropitys bistriata, the type species, can be found at Chemnitz petrified forest, Chemnitz, Germany.


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