Rit (Vísindafélag Íslendinga) - 01.06.1984, Page 224
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12
PÁLL IMSLAND
APATITES
37
324 175
37
70
70
324
324
168 70 168 324 175 324 324 329
37
89
89
70
70
70
329
324
324
324
37
69
69
89
70
87
329
52
69
329
329
52
70
329
329
329
329
329
86 88 90 92 94 96 98 100
Sum of analyses (wt.%)
Fig. 113. Histogram of sums of apatite analyses, before addition of H20 but after
subtraction of F and CI in excess of O. Numbers in boxes are rock sample
numbers. The average of all 44 sums is 94.7 per cent.
does not vary much, in spite of lower totals. The recalculation of CaO and
P205 has been done without changing this ratio and is thus a simple
addition ofCaO and P205 in equal proportions to the original ones, to give a
final total of ~99.5 wt. per cent. After this recalculation H20 is calculated as
described above.
Representative analyses of the Jan Mayen apatites are given in Table 35,
where both original and recalculated CaO and P205 values are reported as
well as the calculated H20 content. In addition to the major elements, Ca
and P, íive trace elements, Si, Sr, Fe, Mn and Mg, were determined in the
apatites as well as the two volatile elements, F and Cl.
As the apatite is not a solid solution mineral as regards major elements,
the CaO and P205 concentrations (after “correction”) of the apatites of all
rock types are at the same level; CaO around 54 and P205 around 42 wt. per
cent. As regards volatiles, on the other hand, igneous apatite may be looked
upon as a solid solution mineral between the three components: Ca5
(P04)30H, Ca5(P04)3F and Ca5(P04)3Cl which, according to Deer et al.
(1962), are apparently able to mix in all proportions, even though the C1