Chemistry Reference
In-Depth Information
2
1
3
Metamorphic rocks
Metamorphic rocks
Metamorphic rocks
48
46
San-Antonio complex (1)
San-Antonio complex (2)
San-Antonio complex (3)
4
5
6
Pyroxenites
Metamorphic rocks
Granodiorite
Kok-18
Kok-17
San-Antonio complex (4)
Peninsular Ranges
Koksharovsky massif
Figure 6.1
Chondrite-normalized REE patterns for titanites from pyroxenites, granodiorites, and some
metamorphic rocks. Dotted lines show the patterns for maximum and minimum REE-
compositions of individual grains of titanites (data Table 6.1).
Figure 6.2
The graph of coefficients of REE distribution between titanite and trachite-andesitic melt
(data [Kay & Gordillo, 1994]).
in the titanite structure [Seifert & Kramer, 2003]: 1) Ca
2+
+
Ti
4+
→
REE
3+
+
(Al, Fe)
3+
;
2) 2Ca
2+
Fe
2+
.
In conclusion of this summary of the information available to date on the regulari-
ties of REE distribution in titanites, let us pay attention to one important aspect of this
problem. Perkins & Pearce [1996] while considering the optimization techniques for
the REE analysis in bulk samples of titanite-bearing rocks using the ICP-MS method,
drew attention to the fact that the presence in these rocks of more or less significant
amounts of accessory titanite should be taken into account when interpreting the
results of the analysis. Their opinion is based on the grounds that titanites along with
+
Ti
4+
→
2REE
3+
+
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