کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4701308 | 1637776 | 2006 | 9 صفحه PDF | دانلود رایگان |
The pattern of minor elements incorporation in columbites from granitic pegmatites of Alto Ligonha, Mozambique, was disclosed on the basis of synchrotron radiation X-ray fluorescence (SRXRF) data. Major elements (Fe, Mn, Nb, Ta) were analyzed with an electron microprobe (EPMA).Minor and trace element contents display a common general trend pointing towards the preferential uptake of metals that minimize the stress induced in the host crystal structure by the non-commensurability of cations with distinct valences and ionic radii. The simultaneous incorporation of Ti, Zr, U, Pb, Y and W assures electrostatic equilibrium, being conditioned by the dominant presence of niobium, while Sc concentrates in solid solutions with low Nb / (Nb + Ta) ratios.
Journal: Chemical Geology - Volume 225, Issues 3–4, 31 January 2006, Pages 402–410