Geochemistry of the Neoarchaean Volcanic Rocks of the Kilimafedha Greenstone Belt, Northeastern Tanzania
Table 2
Sm-Nd isotopic data for the Kilimafedha greenstone belt volcanic rocks.
Sample
Rock suite
Sm (ppm)
Nd (ppm)
147Sm/144Nd
143Nd/144Nd
εNd (at 2.7 Ga)
TDM (Ma)
MU 14
Tholeiite basalts
1.68
6.57
0.1545
0.511995
2.18
2980
MU 69
6.12
18.82
0.1965
0.512731
1.87
3763
MU 49
Transitional intermediate volcanic rocks
6.09
29.4
0.1252
0.511451
1.82
2923
MU 57
5.06
24.2
0.1263
0.511481
1.99
2910
MU 68
6.08
33.3
0.1103
0.511218
2.46
2846
MU 89
6.02
28.7
0.1267
0.51148
1.83
2926
MU 100
5.45
24.6
0.1339
0.511594
1.57
2970
MU 16
Rhyolites
1.94
6.81
0.1721
0.512459
5.10
2557
MU 17
1.37
4.51
0.1835
0.512378
−0.51
3914
Calculations are based on a decay constant of 6.54 × 10−12 per year for 147Sm and DM values for Nd are (143Nd/144Nd)today = 0.51316, (147Sm/144Nd)today = 0.2137.
