Re-evaluating digestion methods for highly siderophile element and 187Os isotope analysis: Evidence from geological reference materials

Highly siderophile element and 182 W evidence for a partial late veneer in the source of 3.8 Ga rocks from Isua, Greenland

“…Relevant standard solutions of HSE, Hf, Y, Zr, Mo and Cd were run at the start, during and end of the analytical session to correct for mass bias and isobaric interferences from oxide species (combined corrections <1% for Ir, Pt, Re and ~3% for Pd and Ru). The TDB-1 reference material gave the values in Table 1, in good agreement with those of a recent comprehensive analytical study (Ishikawa et al, 2014). Procedural blanks were typically insignificant (e.g.…”

Disequilibrium-induced initial Os isotopic heterogeneity in gram aliquots of single basaltic rock powders: Implications for dating and source tracing

“…1 and 2), suggesting disequilibrium-induced smallscale initial Os isotopic heterogeneity. Similar Re-Os isotopic features have been documented in other international reference mafic-ultramafic rocks, such as TDB-1 and WGB-1 (Ishikawa et al, 2014;Li et al, 2014;Chu et al, 2015). These data indicate initial Os isotopic heterogeneity (i.e., the coexistence of Os-bearing phases with variable Os isotopic compositions) during the formation of these rocks.…”

“…As described by Ishikawa et al (2014) Ishikawa et al, 2014), suggesting that contamination during analyses is unlikely to be a significant consideration.…”

“…Several recent studies have conducted replicate Re-Os isotope analyses of individual powders (~200 mesh in size) of mafic-ultramafic rocks (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014). In these studies, replicate analyses of each sample defined a good apparent isochron; the derived apparent isochron ages and initial Os isotopic compositions were used to constrain the timing of geological events and to trace the characteristics of mantle sources (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014).…”

“…In these studies, replicate analyses of each sample defined a good apparent isochron; the derived apparent isochron ages and initial Os isotopic compositions were used to constrain the timing of geological events and to trace the characteristics of mantle sources (Meisel et al, 2001;Ishikawa et al, 2014;Li et al, 2014). In light of the nugget effect for both Re and Os concentrations, it is possible that the Os isotopic compositions of individual hand-specimen samples were not totally homogenized when the rocks formed.…”