Caracterização mineral do caulim associado ao pegmatito Cristo Rei, Domingos Martins - ES (região sudeste do Brasil)
Bibliographic record
Abstract
RESUMO - No sudeste do Brasil, inúmeros depósitos de caulim associados a pegmatitos intemperizados são conhecidos mundialmente através da Província Pegmatítica Oriental do Brasil. O pegmatito Cristo Rei, localizado em Domingos Martins (centro-sul do Espírito Santo), é um exemplo desse contexto, que além da relevância científica, representa uma condicionante geológica de importância socioeconômica local. Ele apresenta potencial para exploração de minerais-gemas, argilominerais, rochas ornamentais, minerais industriais e minerais com elementos terras raras. Este estudo teve como objetivo investigar a variação da composição mineralógica e geoquímica dos argilominerais derivados desse pegmatito, visando compreender mecanismos de formação, evolução e controles geomorfológicos e hídricos associados à sua distribuição. Foram aplicadas técnicas de Microscopia Eletrônica de Varredura (MEV) e Difração de Raios X (DRX), permitindo identificar e caracterizar caulinita, halloysita e gibbsita. Os resultados revelam um gradiente evolutivo controlado por relevo, drenagem e estágio de intemperismo: I) caulinita predomina em zonas de drenagem ativa, encostas e fundos de vale; II) halloysita ocorre em áreas com umidade e drenagem sazonal; III) gibbsita é dominante nos topos de morro, com lixiviação e intemperismo avançado; IV) em zonas intermediárias ocorrem fases transicionais. Os dados confirmam um gradiente típico de caulinitização controlado pela dinâmica geomorfológica e hídrica. Conclui-se que o pegmatito Cristo Rei constitui um modelo genético de depósitos de alteração hidrotermal e intempérica, com potencial para prospecção seletiva de argilominerais de alto valor tecnológico e econômico. Palavras-chave: Argilominerais industriais. Halloysita. Caulinita. Gibbsita. Província Pegmatítica Oriental do Brasil. ABSTRACT - In southeastern Brazil, numerous kaolin deposits associated with weathered pegmatites are known worldwide through the Eastern Pegmatitic Province of Brazil. The Cristo Rei pegmatite, located in Domingos Martins (south-central Espírito Santo), is an example of this context, which, in addition to its scientific relevance, represents a geological condition of local socioeconomic importance. It presents potential for the exploration of gem minerals, clay minerals, ornamental rocks, industrial minerals, and minerals with rare earth elements. This study aimed to investigate the variation in the mineralogical and geochemical composition of clay minerals derived from this pegmatite, seeking to understand the mechanisms of formation, evolution, and geomorphological and hydrological controls associated with its distribution. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques were applied, allowing the identification and characterization of kaolinite, halloysite, and gibbsite. The results reveal an evolutionary gradient controlled by relief, drainage, and weathering stage: I) kaolinite predominates in areas of active drainage, slopes, and valley bottoms; II) halloysite occurs in areas with humidity and seasonal drainage; III) gibbsite is dominant on hilltops, with leaching and advanced weathering; IV) transitional phases occur in intermediate zones. The data confirm a typical kaolinitization gradient controlled by geomorphological and hydrological dynamics. It is concluded that the Cristo Rei pegmatite constitutes a genetic model of hydrothermal and weathering alteration deposits, with potential for selective prospecting of clay minerals of high technological and economic value. Keywords: Industrial clay minerals. Halloysite. Kaolinite. Gibbsite. Eastern Pegmatite Province of Brazil.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".