Apatites - Rare Earth Elements in Ultramafic and Mafic Rocks and their Minerals - page 175

Gabbro Pyroxenite

Hawiite

Tab-1

Skaergaard massif

Aldan province

Texas State

Basanite Granitic pegmatites Granitic pegmatites

South Dakota State (1)

Arizona State

South Dakota State (2)

Carbonatite

Kok-19

Koksharovsky massif

Figure 5.1 Chondrite-normalized REE patterns for apatites from gabbro (1), pyroxenite (2), hawaiite (3),
basanite (4), granitic pegmatites (5, 6), and carbonatite (7) (data Table 5.1).

while the value of (Ce/Yb) n in the mineral from hawaiite was higher ( ∼ 107) than in the

sample from basanite ( 79) (Figure 5.1, 3, 4).

The apatites from granitic pegmatites from the State of South Dakota (USA) were
identified to have significantly lower total REE contents in comparison with the min-
eral from previous objects. In their patterns that have a common shallow negative
slope there are positive Eu anomalies of various intensity (Figure 5.1, 5, 6). Apatites
from carbonatites of Koksharovsky alkaline ultramafic massif (Primorie province,
Russia) have a higher total REE content and their REE patterns are almost rectilinear
lines with steep negative slope (Figure 5.1, 7).
Apatites from kimberlites of Benfontein sill (South Africa) show much higher
chondrite-normalized La contents in comparison with their samples from kimberlites
of Wesselton province, while both have almost rectilinear patterns with a very steep
negative slope [Jones & Wyllie, 1984] (Figure 5.2). These authors assumed that signif-
icant differences in the level of REE accumulation in apatites of these two kimberlite
manifestations are due to the mineralogical-structural differences of rocks containing
them. In particular, relatively large and fairly rare apatite grains from kimberlites of
Benfontein sill are in parageneses with perovskite, while they are mainly concentrated

∼