“…However, a series of recent studies using high precision multiple collector-inductively-coupled-plasma-mass spectrometry (MC-ICP-MS) and thermal ionization mass spectrometry (TIMS) have revealed that the isotopic homogeneity for many elements in meteoritic materials are not warranted (e.g., Mo, Yin et al, 2002b;Dauphas et al, 2002;Becker and Walker, 2003;Ba, Hidaka et al, 2003;Ranen and Jacobsen, 2006;Carlson et al, 2007;Nd, Sm, Andreasen and Sharma, 2006;Carlson et al, 2007;Cr, Trinquier et al, 2007;Ni, Regelous et al, 2008;W, Qin et al, 2008;Os, Brandon et al, 2005;Yokoyama et al, 2007). Qin et al (2008) first reported the significant level of 184 W deficiencies iñ 0.1ε units from the IVB iron meteorites. The resulting variations in the isotopic composition of 184 W found in the IVB iron meteorites was attributed to reflect the heterogeneous distribution of s-and r-process nuclides at the nebula scale for the source materials of parent body of the IVB irons accreted (an asteroid of ~2-4 km radius; Haack et al, 1990).…”