Osmium has seven naturally-occurring isotopes, all of which are stable:
and (most abundant) 192Os. 187Os
is the daughter of rhenium-187 (half-life 4.56 x 1010
years: Luck and Allègre, 1983) and is most often measured in a 187Os/186Os
ratio. This ratio, as well as the 187Re/187Os
ratio, have been used extensively in dating terrestrial as well as meteoric
rocks. However, the most notable application of Os in dating has been in
conjunction with iridium, to analyze the layer of shocked quartz along
the K-T boundary (Luck and Turekian, 1983).
Source of text: This review was assembled by Dan Snyder
from the references below.
||Bowen, R. (1988). Isotopes in the Earth Sciences. Elsevier Applied
Science, New York, 647 p.
||Faure, G. (1986)."The Re-Os method of dating", in Principles
of Isotope Geology, Second Edition. John Wiley and Sons, New York,
||Luck, J.M., and Allègre, G.J. (1983). "187Re-187Os
systematics in meteorites and cosmological consequences." Nature,
||Luck, J.M., and Turekian, K.K. (1983). "Osmium-187/Osmium-186 in
manganese nodules and the Cretaceous-Tertiary boundary." Science,