Geochemical relationship between REE and PGE in mafic and ultramafic rocks and their petrogenetic significance - Rare Earth Elements in Ultramafic and Mafic Rocks and their Minerals - page 234

Table 10.4 (Continued).

Massifs

Karaossky Maysky Bulkinsky

M-27-98 M-30-98 2150 2530 2530-1 Bl-17 Bl-4 Bl-7

Olivine
gabbro
leuco-
cratic

Gabbro-
anortho-
site

Troctolite
leucoc-
ratic

Gabbro-
norite Element Websterite Wehrlite Olivine gabbro

Pd 0,78 1,11 1,65 N.d. 0,82 24,0 1,54 1,03

Pt 13,0 5,48 4,05 5,55 3,45 10,5 8,03 23,2

Ru 6,56 3,95 2,35 1,99 2,02 0,25 2,15 1,90

Ir 0,29 0,90 0,16 0,22 0,15 0,041 0,11 0,016

Total
PGE

20,6 11,4 8,21 7,76 6,44 37,8 11,8 26,1

Pt/Ir 45 6 26 25 23 257 74 1449

Pd/Ir 2,69 1,23 10,3 N.d. 5,47 585 14,0 64,4

La 3,88 0,789 3,39 3,11 14,1 0,694 0,981 0,568

Ce 11,8 1,70 7,71 7,89 28,82 1,348 3,060 1,208

Pr N.d. N.d. N.d. N.d. N.d. N.d. N.d. N.d.

Nd 11,3 1,23 5,26 5,47 15,7 0,786 3,44 0,703

Sm 3,23 0,336 1,350 1,380 3,021 0,159 1,195 0,140

Eu 0,910 0,136 0,680 0,618 0,975 0,239 0,668 0,274

Gd 3,71 0,395 1,45 1,47 2,71 0,166 1,56 0,125

Tb 0,647 0,068 0,259 0,250 0,413 0,025 0,286 0,019

Dy 3,79 0,424 1,64 1,52 2,23 0,146 1,78 0,115

Ho 0,739 0,088 0,346 0,295 0,413 0,027 0,344 0,024

Er 2,091 0,234 1,03 0,825 1,11 0,077 0,924 0,058

Tm 0,306 0,034 0,168 0,120 0,162 0,014 0,128 0,010

Yb 1,84 0,244 1,05 0,770 0,968 0,077 0,761 0,067

Lu 0,248 0,039 0,154 0,110 0,142 0,009 0,103 0,010

(La/Yb) n 1,42 2,19 2,18 2,73 9,85 6,05 0,87 5,69

(Eu/Eu*) n 0,80 1,14 1,48 1,32 1,02 4,46 1,50 6,23

Note: The analyses were done in the Analytical Center of IGM SB RAS (analysts S. Palesskii, I. Nikolaeva,
O. Koz'menko). Detection limits of PGE (ppb): Os - 0,07; Ir - 0,002; Ru - 0,005; Pt - 0,07; Pd - 0,09. N.d. - no data.

which indicates that during the crystallization of their parent melt, no significant
fractionation of plagioclase crystals occurred (Figure 10.3, 1-3).
The REE patterns of gabbro, olivine gabbro and wehrlite of Mazhalyksky
massif, that have steep negative slopes, are complicated by positive Eu anomalies
due to fractionation of plagioclase (Figure 10.3, 4-6). In the rocks of Karaossky
massif the lowest REE contents are observed in wehrlite, slightly higher in gabbro-
norite, and much higher in websterite. The REE distribution patterns in all these
rocks have a common negative slope (Figure 10.3, 7-9). It was already mentioned,
that rocks of Maysky massif differ from samples of other massifs by a gener-
ally high REE content and especially LREE content. Similar configuration of REE