Contribuições ao estudo de corpos pegmatíticos na região de São Tomé, Rio Grande do Norte: Mapeamento Geológico, Geologia Estrutural e Geoquímica
The present work seeks to update the cartography of an area located to the west-southwest of the city of São Tomé, Rio Grande do Norte, with emphasis on the pegmatitic bodies in the surroundings of an extended NNE dome structure. This work also aims at describing the petrographic, structural and geo...
Na minha lista:
| Autor principal: | |
|---|---|
| Outros Autores: | |
| Formato: | bachelorThesis |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
|
| Assuntos: | |
| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/34371 |
| Tags: |
Adicionar Tag
Sem tags, seja o primeiro a adicionar uma tag!
|
| Resumo: | The present work seeks to update the cartography of an area located to the west-southwest of the city of São Tomé, Rio Grande do Norte, with emphasis on the pegmatitic bodies in the surroundings of an extended NNE dome structure. This work also aims at describing the petrographic, structural and geochemical characteristics of these bodies. The work involved field activities, bibliographical survey and interpretation of remote sensors images to refine the cartography of the study area. The correlation of the local structures with the orientations and structural signature observed in the pegmatites was studied, in order to understand the control of these in their accommodation. In addition, samples of K-feldspars were collected for analysis of major, minor and trace elements by ICP-OES and ICP-MS, whose results were used in geochemical diagrams of correlation between elements to discuss, from an exploratory perspective, the potential of mineralization of these bodies. In addition, the potential of tantalum mineralization in the form of tantalite of a pegmatite named Caboclo, located in the south of the dome structure, is discussed, using geochemical analyzes in micas. The results obtained include the recognition of a pegmatitic granite in the center of the dome, not previously mapped on previous maps, and several similar bodies nearby. The granitic pegmatites of the heterogeneous type, identified, usually show an incipient zonation, with development mainly of the intermediate zone and of a quartz nucleus. Structural analysis indicates that the main structure that controlled the accommodation of these bodies was the foliation surface S3, formed at a transcurrent regime during D3. The correlation diagrams between the K/Rb ratio versus Rb, Cs, Ga and Ba show that the set of pegmatite rocks in the study area are typically little fractionated, which may suggest a low potential for mineralization. The analysis of the micas of the Caboclo pegmatite revealed satisfactory Ta levels but Li is below the expected values to indicate a good probability of economically viable occurrences of tantalum in tantalite. |
|---|