The consistently increasing need of obtaining information and data about the trace element content in geological material as applied to exploration as well as the investigation of the weathering process of ores demands the utilization of the semiquantitative spectrographic procedures. These procedures provide such data both rapidly and at a relatively low cost. The laboratories of the Companhia de Pesquisa de Recursos Minerais (C.P.R.M.), Brazil, use methods of semiquantitative spectrographic analysis to obtain this kind of information. The work is based upon the previous studies described by Oda and others and Grimes and Marranzino.
Gloria Berenice, C. T. C. B. Da Silva, and Vania N. A. Mello, "A Method of Interpreting Geochemical Results Obtained by a Six-Step Semiquantitative Spectrographic Procedure," Appl. Spectrosc. 29, 269-271 (1975)