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  2. Volcanic ash - Wikipedia

    en.wikipedia.org/wiki/Volcanic_ash

    454 million-year-old volcanic ash between layers of limestone in the catacombs of Peter the Great's Naval Fortress in Estonia near Laagri. This is a remnant of one of the oldest large eruptions preserved. The diameter of the black camera lens cover is 58 mm (2.3 in). Volcanic ash is formed during explosive volcanic eruptions and phreatomagmatic ...

  3. Andisol - Wikipedia

    en.wikipedia.org/wiki/Andisol

    ABwC. Parent material. tephra. In USDA soil taxonomy, andisols are soils formed in volcanic ash and defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite. [1] In the World Reference Base for Soil Resources (WRB), andisols are known as Andosols.

  4. Petrified wood - Wikipedia

    en.wikipedia.org/wiki/Petrified_wood

    Petrified wood (from Ancient Greek πέτρα meaning 'rock' or 'stone'; literally 'wood turned into stone'), is the name given to a special type of fossilized wood, the 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 Petrifaction is the result of a tree or tree-like plants having been replaced by stone via a mineralization process that often ...

  5. What you need to know about volcanic ash

    www.aol.com/know-volcanic-ash-195524299.html

    Volcanic ash accumulates on buildings, and its weight can cause roofs to collapse. A dry layer of ash 4 inches thick weighs 120 to 200 pounds per square yard, and wet ash can weigh twice as much. ...

  6. Tephra - Wikipedia

    en.wikipedia.org/wiki/Tephra

    Tephra is any sized or composition pyroclastic material produced by a explosive volcanic eruption and precise geological definitions exist. [2] It consists of a variety of materials, typically glassy particles formed by the cooling of droplets of magma, which may be vesicular, solid or flake-like, and a varying proportions of crystalline and ...

  7. Acacia koa - Wikipedia

    en.wikipedia.org/wiki/Acacia_koa

    In deep volcanic ash, a koa tree can reach a height of 30 m (98 ft), a circumference of 6 m (20 ft), and a spread of 38 m (125 ft). [7] It is one of the fastest-growing Hawaiian trees, capable of reaching 6–9 m (20–30 ft) in five years on a good site.

  8. Serengeti volcanic grasslands - Wikipedia

    en.wikipedia.org/wiki/Serengeti_volcanic_grasslands

    Serengeti volcanic grasslands. The Serengeti volcanic grasslands is a tropical grassland ecoregion of Tanzania. The Serengeti volcanic grasslands are distinctive grasslands growing on deposits of volcanic ash in northern Tanzania. It includes the eastern portion of Serengeti National Park and areas south and east of the Ngorongoro Highlands.

  9. Petrifaction - Wikipedia

    en.wikipedia.org/wiki/Petrifaction

    Tree remains that have undergone petrifaction, as seen in Petrified Forest National Park. In geology, petrifaction or petrification (from Ancient Greek πέτρα (pétra) 'rock, stone') 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.