抄録
Recently, the precise isotope ratios of some refractory elements in meteorites have been reported using inductively coupled plasma mass spectrometry. The in situ decay of 182Hf (T1/2=9 Myr), which was produced at the latest nucleosynthesis, is recognized in many meteorites as isotopic anomalies of its daughter isotope, 182W. The degrees of relative 182W isotopic deviation in extra-terrestrial and terrestrial silicate samples vary from +0.3 % to ?-?0 % related to the size of their parent bodies. One ready interpretation of its correlation is the difference in timing of metal-silicate separation in the parent bodies. Between the earth and meteorite parent bodies, the difference is calculated to be about four times of the half-life of182Hf, equivalent to 36 Myr.
