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The term dubiofossil is a
portmanteau word
A portmanteau word, or portmanteau (, ) is a blend of wordsfossil
A fossil (from Classical Latin , ) 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 ...
) or abiogenic (i.e., pseudofossil), the information available at the time of study is insufficient to make an unambiguous determination. They belong to the dubiofossil category temporarily, awaiting additional evidence that will allow them to be removed from this category and attributed to the fossils or the pseudofossils. For example, see
ALH84001
Allan Hills 84001 (ALH84001) is a fragment of a Martian meteorite that was found in the Allan Hills in Antarctica on December 27, 1984, by a team of American meteorite hunters from the ANSMET project. Like other members of the shergottite– na ...
.
Physical and chemical processes can produce structures that look indistinguishable from some that are formed by biologic activity, presenting a hurdle in their interpretation.
Living systems are capable of metabolism, reproduction, mutation, and propagation of the mutations. Lines of evidence for biogenicity, called
biosignature
A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
s, come in various forms and appear at various scales, ranging from the atomic to the planetary dimension.
Molecule-building, cell division, colony formation, respiration, excretion, active motility are amongst the biologic processes that effect changes in the environment and can leave distinctive morphologic features or signature chemical by-products in the geologic record.
These attributes are susceptible to be modified or obliterated over geologic time, making it more difficult to recognize them in the rocks. The case for biogenicity is most robust when multiple lines of evidence converge.
References
*Hofmann, H.J., 1972: Precambrian remains in Canada: fossils, dubiofossils, and pseudofossils.
International Geological Congress, 24th Session, Montreal, Proceedings of Section 1, p. 20-3 Fossils