School of Engineering and Science - Jacobs University

espectively). Previous workers have observed that many metals with very low
abundances in CRMs are likely present at concentrations lower than initially reported,
and that early data compilations frequently overestimate the true abundance of these
elements (e.g., Dulski, 2001; Yu et al., 2001), perhaps due to older, less sensitive
analytical techniques. It is therefore suggested that the apparent ‘low’ concentrations
for Co and Ni determined at JUB may reflect this observation, though the limited
published data and few JUB analyses of FeR-4 indicate that more work regarding
these elements is necessary.
The Ti concentration determined in this study and the literature reference
value (327 mg/kg and 420 mg/kg, respectively), both seem high enough to suggest
that accurate Ti analyses in FeR-4 are possible. However the Ti reference value is
compiled from analyses utilizing sample fusion and X-ray fluorescence (XRF)
measurements (Abbey et al., 1983), which may suffer from relatively high blanks
from the flux used during sample fusion, and/or poor detection/quantification limits
compared to ICPMS measurements. It is therefore possible that the true Ti abundance
in FeR-4 is lower than 420 mg/kg, and the discrepancy between the JUB data and the
compiled reference average rather reflects the limited sensitivity and precision of
many of the Ti analyses of FeR-4.
IF-G
The IF-G iron-formation is the most Fe-rich and Al-poor IF utilized as a CRM
within the Geochemistry Lab, with 55.9% Fe 2 O 3 , 41.2% SiO 2 , and 0.15% Al 2 O 3 .
Unfortunately, IF-G as prepared by the issuing organization (IWG-GIT, Table 1)
during the original processing run (first lot) is no longer available, and subsequently a
second lot of IF-G was prepared by IWG-GIT. For many of the earliest IF analyses
performed within the Geochemistry Lab, IF-G was the preferred CRM, and as a result
the aliquot of the original first lot IF-G powder was completely consumed. In June
2007 an aliquot of the second lot of IF-G powder was obtained from IWG-GIT, which
subsequently has been analyzed several times. As reported by IWG-GIT, the only
differences between the two IF-G lots regard the concentrations of Cr, Co, and W. As
Co and W are relevant to this discussion, it is noted that Co and W concentrations in
the second IF-G lot are significantly lower than those originally reported for the first
IF-G lot, due to different crushing methods utilized during preparation of the two lots.
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