Determinação de elementos maiores em granitóides do Cinturão de rochas verdes de Manica e sua interpretação geológica

Abstract

The present work had as objective the determination of the contents of the elements Al, Fe, Si, Ti, Ca, Mg and Mn in the form of oxides in granitoid samples, using the technique X-ray fluorescence spectrometry (XRF) and their interpretation samples in terms of mineral constituent elements. For the control of the experimental results of the accuracy of the “XRF” technique, Two (2) reference materials (MR), NCSD86317, SARM-3 and one standard internal TRH-B. In NCSD86317, the accuracy was good for all elements (Al, Fe, Si, Ca and Mn), with% Er ranging from 0.00% to 5.63%, the accuracy was good with% RSD ranging from 1.19% to 14.43%. The exception was for the element Mg, which presented values high (% Er of 82.42% and% RSD of 28.87%). Results obtained in SARM-3 were also good, with% Er ranging from 0.02% to 4.17% and% RSD which ranged from 0.29% to 4.71%, with the exception of Mg which presented a high value of% Er (32.71%). In TRH-B, the accuracy was good for all elements, with% Er ranging from 0.00% to 12.90%, the accuracy was good with% RSD ranging from 0.87% to 10.20%, presenting Ti a slightly high% RSD value of 22.22%. In the samples,% RSD values ​​between 0.00% to 23.71% were obtained for all elements, generally showing good accuracy, except for Mg in the sample 12MG03 with a% RSD value of 50.00%. Na, K and P contents were given by [31] to be projected the diagrams of variation of larger elements depending on silica, for identification and interpretation geochemical signature of the granitoids under study. From the geochemical classification, it was concluded that the samples under study are acidic, presenting a degree of differentiation from SiO 2 that ranges from 67.50% to 74.13%. You elements Al, Ca, Ti, Mg and Mn showed a correlation with SiO 2 that can reflect the participation of these elements in the fractionation of certain mineral species constituents.