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Fossils are often formed by pseudomorphic replacement of the remains by mineral matter. Examples include petrified wood and pyritized gastropod shells. In biology, a pseudomorph is a cloud of mucus-rich ink released by many species of cephalopod. The name refers to the similarity in appearance between the cephalopod that released it and the ...
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.
Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good ...
Fossils of organisms' bodies are usually the most informative type of evidence. The most common types are wood, bones, and shells. [59] Fossilisation is a rare event, and most fossils are destroyed by erosion or metamorphism before they can be observed. Hence the fossil record is very incomplete, increasingly so further back in time.
Most fossils that have been silicified are bacteria, algae, [3] and other plant life. Silicification is the most common type of permineralization. Silicification is the most common type of permineralization.
In some silicified sedimentary rocks, fossils of diatoms are unearthed. This suggests that diatoms frustules were sources of silica for silicification. [ 13 ] Some examples are silicified limestones of Miocene Astoria Formation in Washington, silicified ignimbrite in El Tatio Geyser Field in Chile, and Tertiary siliceous sedimentary rocks in ...
One common example is when manganese oxides crystallize with a characteristic tree-like or dendritic pattern along a rock fracture. The formation of frost dendrites on a window is another common example of this crystal growth. Concretions are sometimes thought to be fossils, and occasionally one contains a fossil, but are generally not fossils ...
The fossil record is very uneven and, with few exceptions, is heavily slanted toward organisms with hard parts, leaving most groups of soft-bodied organisms with little to no fossil record. [39] The groups considered to have a good fossil record, including a number of transitional fossils between traditional groups, are the vertebrates, the ...