Fe-54 is an isotope of iron. It is the second most abundant isotope in natural iron. The isotope is a daughter product of a nuclear reaction between Fe-56 and a neutron.
The 54Fe isotope is also known as a radioactive isotope of iron. Fe-56 is used to make a variety of isotopes, such as Co-55. This isotope is also used as an electron capture detector.
The range of d56Fe values in sedimentary rocks is a reflection of the diagenesis of the sediments. Typically, organic matter-rich shales have predominantly negative d56Fe values. Similarly, sulfide separates show a range of positive d56Fe values. During the Paleoproterozoic, d56Fe values have been correlated with the evolution of oxygenic photosynthesis.
Although the range of d56Fe values has varied over time, the values of the recent Paleoproterozoic period are consistent with those of the Phanerozoic. For example, the d56Fe value of the pyrite IRMM-014 is -0.09 g/cm2.
In a study of the top 30 cm of the pyrite-rich core from the Santa Barbara basin, Severmann et al. (2006) found that the d56Fe value of the sample matched the d56Fe value of the BIFs from the same horizon. Moreover, the d56Fe value of this sample complemented the isotopic fingerprint of microbial Fe3+ reduction from 2.4 to 2.2 Ga.
As for the origin of the Solar System, 60Ni is believed to have been present in extraterrestrial material. It may have contributed to the remelting of asteroids.
A large amount of d56Fe was produced during the late Archean. It is therefore expected that microbial iron reduction in this period supported the development of oxygenic photosynthesis.