Dottorato di Ricerca in Scienze della Terra (XVI ciclo)

Gruppo Sieniti senza anomalia di Ce Sieniti con anomalia di Ce
Campione K27 K25 K1 K22 K9 K23 K24 K4 K12 K7 K26 K2 K5 K3 K8 K6 K10 K21 K18 K20
Elementi maggiori (%)
SiO 2 62.49 62.68 61.67 61.61 61.95 61.90 62.16 62.42 62.57 60.67 62.40 61.38 63.10 61.26 62.02 62.42 63.04 61.50 62.47 62.31
TiO 2 0.88 0.65 0.83 0.66 0.67 0.56 0.58 0.39 0.49 0.53 0.91 0.68 0.50 0.71 0.68 0.65 0.59 0.67 0.64 0.60
Al 2O 3 16.00 16.07 15.29 15.67 15.43 15.22 15.34 15.19 14.90 13.83 16.77 16.14 16.70 16.00 16.32 16.22 16.48 15.94 15.75 15.20
Fe 2O 3 7.23 6.49 7.56 7.07 6.84 7.29 7.52 6.52 7.66 10.02 6.17 6.15 5.03 6.68 6.51 6.12 5.33 6.23 6.41 7.25
MnO 0.21 0.24 0.30 0.22 0.23 0.25 0.26 0.26 0.29 0.36 0.17 0.17 0.16 0.26 0.22 0.19 0.17 0.23 0.26 0.27
MgO 0.10 0.22 0.31 0.30 0.10 0.15 0.13 0.20 0.24 0.17 0.08 0.24 0.10 0.31 0.15 0.20 0.19 0.17 0.30 0.35
CaO 0.48 0.56 0.84 0.95 0.32 0.50 0.84 0.52 0.66 0.61 0.19 0.59 0.29 0.61 0.41 0.59 0.58 0.45 0.78 0.94
Na 2O 6.82 6.86 6.72 7.44 7.29 7.13 7.62 7.28 7.43 7.47 6.83 6.43 7.16 6.37 6.68 6.79 6.84 6.86 6.89 6.96
K 2O 5.25 5.42 5.41 5.10 5.17 5.28 4.89 5.30 5.12 4.79 5.34 5.44 5.23 5.84 5.61 5.55 5.74 5.34 5.56 5.08
P 2O 5 0.03 0.03 0.02 0.06 0.02 0.04 0.05 0.03 0.03 0.03 0.05 0.03 0.05 0.04 0.03 0.03 0.03 0.04 0.03 0.12
TR 0.20 0.19 0.24 0.21 0.20 0.31 0.28 0.27 0.23 0.23 0.14 0.17 0.18 0.20 0.17 0.20 0.18 0.23 0.23 0.42
LOI 0.78 1.07 0.99 0.38 1.76 1.04 0.70 1.83 0.31 1.12 1.08 1.92 1.28 1.48 1.30 1.01 1.00 2.19 0.57 1.08
Totale 100.48 100.48 100.17 99.67 99.98 99.66 100.38 100.21 99.92 99.83 100.14 99.34 99.78 99.75 100.11 99.97 100.16 99.85 99.89 100.58
REE 2O 3 0.04 0.04 0.03 0.04 0.04 0.05 0.06 0.07 0.05 0.05 0.05 0.04 0.07 0.04 0.03 0.04 0.04 0.06 0.06 0.21
I.P. 1.06 1.07 1.11 1.13 1.14 1.15 1.16 1.17 1.19 1.26 1.01 1.02 1.04 1.05 1.05 1.06 1.06 1.07 1.10 1.11
Norma C.I.P.W (%)
qz 0.17 - - - - - - 0.77 0.59 0.08 0.17 0.26 - - - - - - - 0.03
zr 0.12 0.09 0.16 0.12 0.11 0.21 0.16 0.14 0.12 0.13 0.04 0.09 0.06 0.10 0.11 0.10 0.09 0.10 0.12 0.13
or 31.31 32.40 32.44 30.54 31.29 31.85 29.19 32.04 30.58 28.92 32.03 33.18 31.53 35.33 33.74 33.32 34.37 32.51 33.28 30.42
ab 53.56 53.10 49.24 50.99 51.81 49.91 52.20 49.74 48.65 45.43 57.37 54.42 57.93 50.96 53.64 53.37 53.51 53.83 50.70 50.57
ne - - - 1.03 - - - - - - - - - - - - - - - -
ac 4.12 4.96 6.90 6.45 6.31 6.70 6.84 6.00 6.97 9.21 1.13 1.52 3.42 3.71 3.42 4.40 4.52 5.25 5.84 6.61
ns - - 0.14 0.83 0.98 0.95 1.20 1.50 1.62 2.02 - - - - - - - - 0.40 0.37
di 0.08 0.20 0.37 0.40 0.05 0.10 0.15 0.16 0.21 0.11 0.03 0.30 0.06 0.31 0.11 0.22 0.22 0.13 0.37 0.39
hd 1.88 2.11 3.25 3.46 1.28 1.91 3.29 2.00 2.55 2.46 0.54 2.19 0.96 2.19 1.55 2.25 2.18 1.67 2.92 3.07
en 0.21 0.26 0.24 - 0.23 0.30 0.09 0.44 0.51 0.38 0.19 0.48 0.16 0.10 0.11 0.13 0.06 0.07 0.25 0.70
fs 5.56 3.14 2.42 - 6.48 6.40 2.38 6.39 7.21 10.17 4.37 4.06 3.10 0.80 1.85 1.54 0.72 1.05 2.27 6.26
fo - 0.14 0.26 0.40 - 0.02 0.11 - - - - - 0.05 0.38 0.15 0.19 0.22 0.21 0.23 -
fa - 1.80 2.93 4.38 0.12 0.48 3.14 - - - - - 1.06 3.44 2.66 2.54 2.73 3.50 2.33 -
mt 1.23 0.48 0.00 - - - - - - - 2.26 2.10 0.60 1.23 1.28 0.60 0.17 0.26 - -
il 1.69 1.25 1.59 1.26 1.30 1.08 1.12 0.75 0.94 1.03 1.76 1.33 0.98 1.37 1.31 1.26 1.13 1.31 1.23 1.16
ap 0.07 0.07 0.05 0.14 0.05 0.09 0.12 0.07 0.07 0.07 0.12 0.07 0.12 0.09 0.07 0.07 0.07 0.10 0.07 0.28
Totale 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00
Elementi in tracce e REE (ppm)
Zn 160 184 221 196 142 185 238 229 222 255 160 191 127 187 147 187 162 184 182 266
Ga 36 31 35 36 37 39 38 40 38 42 34 32 38 35 32 32 33 34 33 36
Rb 131 124 140 160 152 168 161 154 133 152 110 115 114 170 118 121 107 134 145 135
Sr 7 17 16 5 5 7 4 12 10 5 8 17 8 15 13 20 16 10 20 22
Y 33 33 17 54 34 42 84 57 39 20 43 35 68 23 23 31 30 47 37 129
Zr 579 445 763 569 518 1,040 800 659 575 639 209 433 287 484 520 507 459 485 577 619
Nb 187 180 229 184 246 311 213 278 224 234 106 122 98 171 123 155 168 295 157 223
Sn 6 4 7 7 6 11 6 5 4 6 2 3 2 4 5 4 4 4 5 5
Cs 0.6 0.9 1.4 1.1 0.7 0.8 1.8 0.6 0.5 0.5 0.7 0.8 0.5 1.7 0.7 0.8 0.8 0.9 1.5 0.8
Ba 28 76 76 37 16 19 22 37 30 9 39 60 38 66 55 89 61 28 110 78
La 92.5 93.5 60.0 82.3 84.5 115 127 142 115 111 174 94.4 230 119 73.9 96.4 86.6 151 170 676
Ce 155 181 114 155 145 209 235 260 191 190 79.1 118 140 79.6 110 128 130 217 130 539
Pr 18.0 16.7 10.1 16.3 14.9 20.6 24.5 26.8 20.6 17.7 28.6 17.0 36.8 19.0 12.6 17.2 15.7 27.7 29.4 93.6
Nd 61.5 55.8 32.4 58.0 49.5 67.1 87.8 89.2 68.6 55.0 92.6 57.2 121 59.6 42.5 57.1 52.4 91.3 96.5 315
Sm 9.5 8.5 4.8 10.4 7.7 10.1 15.6 13.5 9.8 6.5 12.3 8.5 16.4 8.0 6.4 8.6 8.3 13.9 13.7 45.7
Eu 1.09 1.19 0.77 1.11 0.81 0.90 1.35 1.33 0.93 0.43 1.44 1.19 1.88 1.13 1.24 1.27 1.28 1.49 1.80 4.09
Gd 7.4 6.4 3.3 9.0 6.1 7.9 14.1 10.1 7.8 4.0 11.7 7.5 15.8 7.2 5.5 7.1 7.0 11.3 12.4 39.2
Tb 1.1 1.1 0.5 1.6 1.0 1.3 2.4 1.6 1.1 0.5 1.3 1.1 1.9 0.8 0.8 1.0 1.1 1.7 1.5 5.0
Dy 6.6 6.1 3.1 9.3 6.2 7.6 14.6 9.9 6.6 3.3 7.6 6.2 10.7 4.3 4.6 5.7 6.0 9.7 7.9 27.7
Ho 1.3 1.2 0.6 1.9 1.3 1.5 3.0 2.0 1.3 0.7 1.5 1.2 2.1 0.8 0.9 1.1 1.2 1.9 1.4 4.9
Er 3.8 3.7 2.4 5.5 4.0 4.9 8.7 6.6 4.4 2.8 4.2 3.8 6.2 2.7 2.8 3.4 3.4 5.5 4.2 13.4
Tm 0.68 0.71 0.57 0.94 0.74 0.97 1.49 1.29 0.90 0.72 0.68 0.69 1.00 0.56 0.55 0.67 0.62 0.99 0.81 2.12
Yb 4.9 5.2 4.9 6.0 5.2 7.2 9.2 9.0 7.0 6.2 4.0 4.8 6.1 4.3 4.0 4.9 4.4 6.7 5.8 13.1
Lu 0.82 0.91 0.92 0.93 0.84 1.26 1.38 1.54 1.29 1.23 0.57 0.81 0.90 0.77 0.69 0.84 0.71 1.07 0.97 1.88
Hf 15.6 11.3 20.7 14.0 14.3 27.1 20.7 16.2 15.1 16.9 5.1 10.5 7.0 11.7 13.8 13.2 11.3 12.3 15.4 15.7
Ta 10.6 10.2 14.8 9.4 11.0 21.4 13.3 17.3 15.0 12.2 5.6 7.9 6.0 10.6 7.6 10.4 9.5 13.3 11.2 14.0
Th 16.7 22.1 25.7 12.0 18.8 38.3 16.1 24.2 16.6 20.7 7.8 12.4 9.4 20.9 14.4 17.7 14.2 16.1 19.0 23.1
U 4.4 4.4 6.9 4.0 5.3 11.0 4.3 6.6 4.4 4.0 1.8 3.5 2.3 4.3 3.3 4.1 4.4 9.3 4.9 7.3
Ce/Ce *
0.83 0.99 0.99 0.93 0.89 0.93 0.92 0.92 0.85 0.91 0.24 0.64 0.32 0.36 0.77 0.68 0.77 0.73 0.40 0.44
Composizione chimica di roccia totale (elementi maggiori e in tracce) e Norma C. I. P. W. dei clasti
sienitici di Kilombe. I campioni sono disposti in ordine di indice di peralcalinità (I.P.) crescente.
Abbreviazioni: TR = totale degli ossidi degli elementi in tracce, qz = quarzo, zr = zircone, or =
ortoclasio, ab = albite, ne = nefelina, ac = acmite (i.e. egirina), ns = metasilicato di sodio, di =
diopside, hd = hedenbergite, en = enstatite, fs = ferrosilite, fo = fosterite, fa = fayalite, mt =
magnetite, il = ilmenite, ap = apatite, Ce/Ce * = Ce/(La+Pr)/2 (valori normalizzati alle condriti).
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