TEXTURAL AND MICROANALYSIS OF IGNEOUS ROCKS: TOOLS ...

2.5.3.2 Trace Elements
It is difficult to accurately quantify the amount of error introduced by chosen
or calculated partition coefficients. Error bars displayed in figures 2.9 and 2.10,
which can be compared to analytical uncertainty displayed in figure 2.7, repre-
sent the combined potential error related to analytical uncertainty and calculation
of partition coefficients using uncertainty on constants reported by Bindeman et
al. [7]. Parent magmas of xenolith interiors typically exhibit lower La/Y and
Ba/Sr ratios and slightly higher Sr/Ti ratios than phenocryst parent magmas
(Tables 2.2and2.3; Fig. 2.9). Parent magmas of the An-rich xenolith interiors are
also enriched in Sr, Eu, and Y and relatively depleted in Ba, La, Ce, and Nd rela-
tive to phenocryst parent magmas (Tables 2.2, 2.3; Fig. 2.10). Parent magmas of
both xenolith crystals and phenocrysts have Sr, Ba, and Eu abundances that over-
lap published Kwaimbaita and Kroenke basalt whole-rock values, but generally
have lower La, Ce, and Nd abundances (see Table 2.3). Given the potential error
in calculated D values (compare error bars in Figs. 2.7 and 2.10), OJP plagioclase
parent magmas plot in a reasonably consistent manner in terms of La/Y, Sr/Ti,
and Ba/Sr ratios, Mg number, Eu and Sr, compared to the Kroenke, Kwaim-
baita, and Singgalo whole-rock basalt fields (Fig. 2.9; Table 2.3). For example,
the compositions of parent magmas of xenolith interiors from Malaita and Unit
7 of Site 1183 overlap Kroenke and Kwaimbaita basalt fields (see Fig. 2.9). Par-
ent magma compositions of xenolith exteriors and phenocrysts from all three Site
1183 Units and xenolith interior parent magmas from Units 5B and 6 consistently
trend outside of the fields defined by the whole-rock compositions (Fig. 2.9). Par-
ent magmas of the core and rim of phenocryst 63R2P4, the core of 59R2P1, the
rim of 59R2P2, and an exterior zone of xenolith 59R2X-1 are unique, because they
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