Continental crust osmium isotopes

Figure 54 Comparison of present-day osmium isotopic compositions of eclogite xenoliths from Udachnaya, Yakutia (Pearson et ah, 1995c) and S. Africa (Pearson et al, 1992 Menzies et al, 1999 Shirey et ah, 2001) with continental crust, oceanic basalts (Shirey and Walker, 1998), and Archean komatiites and basalts (Walker et al, 1989b). Udachnaya peridotite data from Pearson et al (1995a).

Esser B. K. and TureMan K. K. (1993) The osmium isotopic composition of the continental crust. Geochim. Cosmochim. Acta 57, 3093-3104. 

Peucker-Ehrenbrink B. and Jahn B.-M. (2001) Rhenium-osmium isotope systematics and platinum group element concentrations loess and the upper continental crust. Geochem. Geophys. Geosys. G 3 2001GC000172. 

McBride J. S., Lambert D. D., Nicholls I. A., and Price R. C. (2001) Osmium isotopic evidence for crust—mantle interaction in the genesis of continental intraplate basalts from the Newer Volcanic Province southeastern Australia. J. Petrol. 42, 1197-1218. 

The beta decay scheme of rhenium-187 to osmium-187 maybe applied to the study of sulfide minerals of molybdenum and osmium-rich minerals such as iridosmine. Together with rubidium/strontium, samarium/neodymium, lutetium/hafnium, and uranium/lead methods, it has been used to examine mantle differentiation and the accretion of continental crust. In molybdenites, rhenium concentrations vary from a few ppm to as much as 1.88%. The element has two naturally occurring isotopes, and these are the stable rhenium-185 with a relative abundance of 37.398% and the radioactive rhenium-187 with a relative abundance of62.602%. This decays as follows ... 

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