Fossils ( Latin fossilis - fossil, fossil in paleontology ) - fossilized remains of organisms or traces of their vital activity , dating back to previous geological eras .
Fossilia provide important information about the organisms of their education. They can be found during excavations or they are exposed as a result of erosion . There are analysis methods that allow you to approximately determine the time of their formation or preservation.
Fossils are usually remnants (not to be confused with human remains ) or imprints of animals and plants preserved in soil , stones, and hardened resins . Quite often in this way only the solid parts of the animal’s body are preserved - shells , teeth , bones , which are often replaced by mineral matter. Soft tissues decompose, however, the soft tissues of a petrified organism can sometimes be judged by the results of their interaction with the surrounding material (change in shape or chemical composition). Fossils also include conserved traces of, for example, the feet of an organism on soft sand, clay or mud.
Fossilia can be understood as any non-modern residues or traces of living organisms, but often this term is used in a narrower sense to refer only to those residues and traces that are found in the Pre-Pleistocene deposits and went through the process of fossilization  . Such remains and traces are also called fossils   .
Fossilization - a set of processes of transformation of dead organisms into fossils. It is accompanied by the influence of various environmental factors and the passage of diagenesis processes - physical and chemical transformations, during the transition of sediment to the rock in which they are included .
After the death of the body, first of all, the destruction of soft tissues occurs, then - filling the voids of the skeleton with mineral compounds. Sometimes the voids of the skeleton are pyritized, ironized, drusen and inclusions of calcite , amethyst , fluorite , galena , etc. may appear in them. During fossilization, the skeleton undergoes recrystallization, leading to stable mineral modifications. For example, aragonite mollusk shells are converted to calcite. There are known cases of mineralization when the primary chemical composition of the skeleton changes (pseudomorphs). So, calcareous shells are partially or completely replaced by aqueous silica and vice versa. Sometimes phosphatization , pyritization and ironization of mineral and organic skeletons are observed.
Plants with fossilization usually [ when? ] are completely destroyed, leaving the so-called. fingerprints and nuclei, however, their remains are found in fossil form starting from Precambrian (fossilized organic matter  ).
Dead tissue can be replaced by mineral compounds ( pseudomorphs ), most often silica , carbonate and pyrite . Such complete or partial replacement of plant trunks while maintaining the internal structure is called petrification. .
Subfossilia ( lat. Sub - under, almost) - fossils that have preserved not only the skeleton, but also weakly modified soft tissues. For plant residues, the term “phytolimes” is used ( dr. Greek. Φυτόν - plant; λεῖμμα - residue). They are represented to varying degrees by altered plant residues that preserve the cellular structure. Subfossils include phytolimes from Quaternary sediments - seeds , nuts , conifer cones , wood buried in peat bogs .
The subfossils also include unique finds of some animals, such as mammoths , rhinos and birds. Preservatives in such cases are permafrost , various bitumen , volcanic ash, aeolian sands. Amber was previously thought to be a good preservative, but soft tissues are not preserved in it. Fossil plants and animals in amber completely retain their shape, which allows you to carefully study their external morphology. But an attempt to extract objects ends in the fact that all their contents are scattered into dust.
Subfossils are often considered not as a variety of fossils, but as an independent category of objects of paleontological research equivalent to them  .
Eufossilia, or euphosphilia ( dr. Greek. Εὖ - well) are represented by whole skeletons or their fragments, as well as prints and nuclei. Skeletal residues have a mineral or organic composition. These include shells and skeletons of animals, shells of bacteria and fungi, as well as organic remains of leaves, seeds, fruits, spores and pollen. Skeletons are the main objects of paleontological research. Sometimes the term "organic-walled microfossils" is used, which includes the shells of bacteria and fungi, filamentous cyanobacteria , as well as spores and pollen. The sizes of such fossils are less than 100 microns. Many euphosilia store information not only about the soft parts of the body and its functional systems, such as the circulatory, reproductive, conducting bundles of plants, etc., but also about lifestyle and biogeochemical processes.
Ikhnofossiliya ( dr. Greek. Ἴχνος - trace) - traces of the vital activity of fossil organisms. Most often they are stored in the form of prints, less often in the form of low-volume formations. These include traces of crawling and burying arthropods , worms, bivalves; traces of eating, mink, passages and traces of drilling sponges, bivalves, arthropods; traces of movement of vertebrates. Paleo-technology is engaged in the study of their fossils .
Coprofossils ( other Greek: κόπρος - litter, manure) are formed by the waste products of fossil organisms. They are voluminous in nature, stored in the form of rollers, nodules, mounds, columns, strata. The most typical coprofossils include the final digestion products of vertebrates, undigested remains of other animals and plants. Usually they are represented by rollers and ribbons enriched with calcium, iron, magnesium, potassium and phosphorus. Coprofossils usually have a lighter or, conversely, darker color, often with a reddish tint, which distinguishes them from the surrounding breed. See also coprolites .
Chemofossilia ( dr. Greek χημία - chemistry) are represented by organic fossil biomolecules of bacterial, cyanobacterial , plant and animal origin. Usually, the chemical composition of biomolecules is preserved, which allows us to determine the systematic position of the fossil organism, but not its morphology. They are an object of study of biochemistry and molecular paleontology.
Along with subfossils, they are often considered not as a variety of fossils, but as an independent category of objects of paleontological research  .
Among the sciences of the geological cycle studying fossilia, many scientific areas are presented, among them:
- Micro paleontology
- Paleontological stratigraphy
- Vertebrate paleontology
- Evolutionary paleontology
- Yanin B.T. Terminological Dictionary of Paleontology. - Moscow: Publishing house of Moscow University, 1990. - 136 p. - 4700 copies. - ISBN 5-211-01069-8 .
- Barskov I.S., Yanin B.T. Methodology and technique of paleontological research. Part I. Methodology of field paleontological and stratigraphic studies. - Moscow: Moscow University Press, 1997. - 104 p. - 500 copies. - ISBN 5-211-03896-7 .
- Uspensky V.A., Radchenko O.A., Smirnova N. B. On the construction of the coalification conversion of fossilized organic matter according to its chemical composition // Chemistry of solid fuels. 1981. No. 2. P. 3-9.
- Efremov I.A. , Taphonomy and the geological record , Prince. 1, M. — L., 1950 (Proceedings of the Paleontological Institute of the Academy of Sciences of the USSR, v. 24);
- Krishtofovich A.N. , Paleobotany, 4th ed., L., 1957;
- Paleontology of invertebrates, M., 1962;
- Abel O., Vorzeitliche Lebensspuren, Jena, 1935.
- Fossils: A Guiding Thread of Nature (Retrieved June 16, 2009)
- Fossilized remains of organisms / V.N. Shamansky // Great Soviet Encyclopedia : [30 t.] / Ch. ed. A.M. Prokhorov . - 3rd ed. - M .: Soviet Encyclopedia, 1969-1978. (Retrieved June 16, 2009)