Radiogenic isotopes mantle geochemistry

Table 1 shows a list of long-lived radionuclides, their half-lives, daughter isotopes, and radiogenic-to-nonradiogenic isotope rates commonly used as tracers in mantle geochemistry. Noble-gas isotopes are not included here, because a separate chapter of this Treatise is devoted to them... 

Patchett P. J. (2003) Provenance and crust-mantle evolution studies based on radiogenic isotopes in sedimentary rocks. In Geochemistry of Sediments and Sedimentary Rocks Evolutionary Considerations to Mineral Deposit—Forming Environments, Geological Association of Canada GEOtext (ed. D. R. Lentz). St. John s, Nfld, vol. 5, pp. 89-97. 

The noble gas geochemistry of natural waters, including formation waters in sedimentary basins, has been used to determine paleotemperatures in the recharge areas, to evaluate water washing of hydrocarbons, and to identify mantle-derived volatiles (Pinti and Marty, 2000). The dissolved noble gases, helium, neon, argon, krypton, and xenon in sedimentary waters, have four principal sources the atmosphere, in situ radiogenic production, the deep crust, and the mantle. These sources have characteristic chemical and isotopic compositions (Ozima and Podosek, 1983 Kennedy et al., 1997). 

Nd/ Nd low 8nneodymium isotopic compositions, the remarkable aspect of the frequency distribution for CLM as a whole is that the pronounced mode is within 58 units of bulk Earth and the mean 8j,jd value is 1.8. On this basis, the dominant neodymium isotopic characteristic of CLM is not enriched but is close to, or slightly more depleted than bulk Earth. Of course, if Depleted Mantle is used as a reference point then the CLM mode is enriched. The strontium isotope frequency distribution has a long tail out to very radiogenic ( enriched ) compositions but the mean Sr/ Sr is 0.7047 very close to estimates of bulk Earth. It is important to bear in mind that this statistical view of CLM geochemistry could... 

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