Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the condition in which they were buried were not optimal for fossilization.
Subfossil remains that date back into the
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
are exceptionally rare, usually in an advanced state of decay and consequently much disputed. The vast bulk of the material comes from
QuaternaryThe Quaternary period is the youngest of three periods of the Cenozoic era in the geologic time scale of the ICS. It follows after the Neogene period, spanning 2.588 +/- 0.005 million years ago to the present...
deposits.
The main importance of subfossil vs.
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
remains is that the former contain organic material, which can be used for
radiocarbon datingRadiocarbon dating, or carbon dating, is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to determine the age of carbonaceous materials up to about 60,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present"...
or extraction and sequencing of
DNAThe term DNA sequencing refers to sequencing methods for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
,
proteinProteins are found in every cell and are essential to every biological process, protein structure is very complex: determining a protein's structure involves first protein sequencing - determining the amino acid sequences of its constituent peptides; and also determining what conformation it adopts...
, or other biomolecules.
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the condition in which they were buried were not optimal for fossilization.
Subfossil remains that date back into the
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
are exceptionally rare, usually in an advanced state of decay and consequently much disputed. The vast bulk of the material comes from
QuaternaryThe Quaternary period is the youngest of three periods of the Cenozoic era in the geologic time scale of the ICS. It follows after the Neogene period, spanning 2.588 +/- 0.005 million years ago to the present...
deposits.
The main importance of subfossil vs.
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
remains is that the former contain organic material, which can be used for
radiocarbon datingRadiocarbon dating, or carbon dating, is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to determine the age of carbonaceous materials up to about 60,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present"...
or extraction and sequencing of
DNAThe term DNA sequencing refers to sequencing methods for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
,
proteinProteins are found in every cell and are essential to every biological process, protein structure is very complex: determining a protein's structure involves first protein sequencing - determining the amino acid sequences of its constituent peptides; and also determining what conformation it adopts...
, or other biomolecules. Additionally,
isotopeIsotopes are different types of atoms of the same chemical element, each having a different number of neutrons. Correspondingly, isotopes differ in mass number but not in atomic number. The difference in the number of nucleons comes from a difference how many neutrons are in the atomic nucleus...
ratios can provide much information about the ecological conditions under which extinct animals lived.
Subfossils are often found in depositionary environments, such as lake sediments, oceanic sediments, and soils. Once deposited, physical and/or chemical
weatheringWeathering is the decomposition of Earth's rocks, soils and minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice,...
can alter the state of preservation, and small subfossils can be ingested by living organisms.
Some common subfossils found in Quaternary sediments include: chironomid head capsules,
ostracodOstracoda is a class of the Crustacea, sometimes known as the seed shrimp because of their appearance. Some 65,000 species have been identified, grouped into several orders. This group may not be monophyletic. Ostracod taxa are grouped into a Class based on gross morphology...
carapaceA carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids as well as vertebrates such as chelonians, order Testudines, turtles and tortoises.-Crustaceans:In crustaceans, the carapace is a part of the exoskeleton...
s, diatoms,
foraminiferaThe Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net. They typically produce a test, or shell, which can have either one or multiple chambers, some becoming quite elaborate...
, and many others.
Subfossils are useful for studying the evolutionary history of an environment, and can be important to studies in
paleoclimatologyPaleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rocks to determine the past state of the climate system on Earth....
.