[U. S. Geological Survey]

Periodic Table--Chromium

Chromium-53 is the radiogenic decay product of 53Mn. Chromium isotopic contents are typically combined with manganese isotopic contents and have found application in isotope geology. Mn-Cr isotope ratios reinforce the evidence from 26Al and 107Pd for the early history of the solar system. Variations in 53Cr/52Cr and Mn/Cr ratios from several meteorites indicate an initial 53Mn/55Mn ratio that suggests Mn-Cr isotope systematics must result from in-situ decay of 53Mn in differentiated planetary bodies (Birck and Allegre, 1985, 1988). Hence 53Cr provides additional evidence for nucleosynthetic processes immediately before coalescence of the solar system.

In addition to the evidence from radiogenic 53Cr, abundances of non-radiogenic 54Cr may also provide constraints on the origin of solar-system material. 54Cr abundances in chondrite samples indicate a mixing of multiple nucleosynthetic components in the formation of the solar-system (Rotaru et al., 1992).

Source of text: This review was assembled by Eric Caldwell, primarily from Dicken (1995).


Birck, J.L. and Allegre, C.J. (1985). "Evidence for the presence of 53Mn in the early solar system." Geophys. Res. Lett., 12: 745-748.

Birck, J.L. and Allegre, C.J. (1988). "Manganese-chromium isotope systematics and the development of the early solar-system." Nature, 351: 579-584.

Dicken, A.P. (1995). Radiogenic Isotope Geology. Cambridge University Press, New York, 452 pp.

Rotaru, M., Birck, J.L. and Allegre, C.J. (1992). "Clues to early solar-system history from chromium isotopes in carbonaceous chondrites." Nature, 358: 465-470.

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