Isotope radiogenic isotopes

Oxygen isotope — radiogenic Isotope correlation diagrams... 

Isotopes are subdivided into radiogenic and stable isotopes. Radiogenic isotopes (Chapter 6) include those isotopes which decay spontaneously due to their natural radioacdvity and those which are the final daughter products of such a decay scheme. They include the parent-daughter element Rb-Sr, Sm-Nd, U—Pb, Th-Pb and K-Ar. They are expressed as rados either in absolute terms Sr/ Sr (e.g.) or relative to a standard (the -notadon) (Table Ul). 

Lead occurs naturally as a mixture of four non-radioactive isotopes, and Pb, as well as the radioactive isotopes ° Pb and Pb. All but Pb arise by radioactive decay of uranium and thorium. Such decay products are known as radiogenic isotopes. 

Analytical solutions. Following the approach of Spiegelman and Elliott (1993), the effects of transport of melt through a melting column on the chemistry of radiogenic isotopes can be separated from melting by expressing the concentration of an element as ... 

Despite the uncertainty about the rate of incorporation of °Thxs into Mn deposits, Th chronology can still provide some useful information about their growth rates. For instance, °Thxs has been used to suggest short-term changes in growth rates of Mn crusts (Eisenhauer et al. 1992) and to check the Be chronologies of crusts used to reconstruct the radiogenic isotope history of seawater (Abouchami et al. 1997 Frank 2002). 

Paradis, S., Turner, W.A., Coniglio, M., Wilson, N. Nelson, J.L. 2006. Stable and radiogenic isotopic signatures of mineralized Devonian carbonates of the Northern Rocky Mountains and the Western Canada Sedimentary Basin. In Hannigan, P.K. (ed) Potential for carbonate-hosted lead-zinc Mississippi Valley-type mineralization in northern Alberta and southern Northwest Territories Geoscience Contributions,... 

In K-Ar or zircon U-Pb dating, modeling the loss of radiogenic isotopes by volume diffusion is important. If P0 is the local concentration at t = 0 of a radioactive element decaying with constant X, a source term exists in the transport equation of the radiogenic element which is the local rate of accumulation AP0e Xt. For dual decay,... 

Let us consider in the first place the total concentration N = C + P0e M of radioactive and radiogenic isotopes. Since there is no loss of the radioactive isotope, the variation of N equals the loss of the radiogenic isotope. In other words... 

The same derivation as that used for the accumulation of radiogenic isotope in a slab would lead to the solution but we will take advantage of this case to fully develop an application of Duhamel s principle (Appendix 8C). The assumption of zero initial and surface concentration of the radiogenic isotope is equivalent to... 

An example can be found in the section dealing with the diffusion of radiogenic isotope out of a sphere. 

White, W. M. (1985). Sources of oceanic basalts radiogenic isotopic evidence. Geology,... 

So far, second-order corrections have only found their application for radiogenic isotopes (see a more extensive treatment in Albarede et al. 2004). The linear changes in the apparent mass bias of Nd with mass observed by Vance and Thirlwall (2002) is certainly an indication that high precision may benefit from such an elaborate scheme on at least some instruments. 

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