Caracterização dos diamantes da província kimberlítica de Juína (MT), e distritos diamantíferos de Espigão D'Oeste (RO), Cacoal (RO) e Diamantina (MG)
Carregando...
Arquivos
Data
2005-11-18
Autores
Filemon, Kelusodi Eduardo [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O Sistema de Processo de Certificação de Kimberley foi instituído pela Organização das Nações Unidas (ONU) no ano 2000. O Brasil que ocupa a nona posição no ranking dos paises produtores de diamantes, aderiu a esse acordo internacional que tem servido como um mecanismo de certificação de origem geográfica de diamantes brutos destinados à exportação e importação. Considerando-se a extrema importância na determinação da procedência dos diamantes brutos. Foi desenvolvida a presente pesquisa visando caracterizar lotes representativos de diamantes da província kimberlítica de Juína (MT), e dos distritos de Cacoal (RO), Espigão Dþoeste (RO) e Diamantina (MG), utilizando técnicas de fluorescência, espectroscopia infravermelha, fotoluminescência (PL), ressonância paramagnética eletrônica (EPR) e Raman, além de estudos de morfologia, texturas de superfícies e granulometria. Os dados obtidos, através da análise estatística de populações das quatro áreas diamantíferas estudadas mostraram predomínio de diamantes de cor marrom em Juína, e de pedras incolores nos distritos do Cacoal, Espigão Dþoeste e Diamantina. A província de Juína destaca-se pela presença de fragmentos irregulares e raríssimos cristais dodecaedros e octaedros, enquanto nos distritos de Diamantina e de Espigão Dþoeste predominam diamantes com hábito dodecaedro. O comportamento ao infravermelho mostrou, na província kimberlítica de Juína uma proporção elevada de diamantes tipo IIa (15%), diamantes tipo IaB (20%) e diamantes tipo IaAB (65%) apresentando este último, alto estado de agregação do nitrogênio. Os diamantes dos distritos de Cacoal, Espigão Dþoeste e Diamantina enquadram-se na classificação do tipo IaAB, variando seu estado de agregação de nitrogênio. Observados sob luz ultravioleta, os diamantes estudados mostraram diferenças nas cores de fluorescência,...
In 2000 the United Nations established the Kimberley Process Certification System in order to avoid illegal diamond trading, especially those from the African continent Brazil, which holds the ninth position in the diamonds trading ranking has joined such international agreement that helps as a geographic origin certification mechanism for exporting and importing. Considering the importance in determining the unpolished diamonds origin, the present study have been developed with the aim objective to describe representative diamond amounts or lots from the Kimberlitic Province of Juína (MT), Cacoal (RO) and Espigao Df oeste (RO) and Diamantina (MG) districts. Using spectroscopy techniques, infrared, photoluminescence, electronic paramagnetic resonance and Raman have been used. In addition, other techniques and procedures such as morphology 1 surface roughness and granulometry were applied. Statistical population analysis of four studied diamond bearing areas indicated several particular characteristics. Where some colors highly predominate in a determined region. Brownish colored diamonds are predominant in Juína provence and colorless crystals are present in Cacoal, Espigão Dþoeste and Diamantina districts. The irregular habit is predominant in Juina Provence but rarely dodecahedral and octahedral crystals were found. In Diamantina and Espigao Dþoeste. Diamonds with dodecahedral habits are predominant. In the Juina kimberlitic province the infrared analysis have shown a high amount of type IIa (15%), type Iab (20%) and type IaAB (65%) diamonds, the last type bearing high nitrogen aggregation. Cacoal, Espigão Dfoeste and Diamantina diamonds were classified as IaAB type showing variations in the nitrogen aggregate state. Ultraviolet analysis showed different fluorescence colors for each province caused by variable rare-earth elements concentrations... (Complete abstract, click electronic access below)
In 2000 the United Nations established the Kimberley Process Certification System in order to avoid illegal diamond trading, especially those from the African continent Brazil, which holds the ninth position in the diamonds trading ranking has joined such international agreement that helps as a geographic origin certification mechanism for exporting and importing. Considering the importance in determining the unpolished diamonds origin, the present study have been developed with the aim objective to describe representative diamond amounts or lots from the Kimberlitic Province of Juína (MT), Cacoal (RO) and Espigao Df oeste (RO) and Diamantina (MG) districts. Using spectroscopy techniques, infrared, photoluminescence, electronic paramagnetic resonance and Raman have been used. In addition, other techniques and procedures such as morphology 1 surface roughness and granulometry were applied. Statistical population analysis of four studied diamond bearing areas indicated several particular characteristics. Where some colors highly predominate in a determined region. Brownish colored diamonds are predominant in Juína provence and colorless crystals are present in Cacoal, Espigão Dþoeste and Diamantina districts. The irregular habit is predominant in Juina Provence but rarely dodecahedral and octahedral crystals were found. In Diamantina and Espigao Dþoeste. Diamonds with dodecahedral habits are predominant. In the Juina kimberlitic province the infrared analysis have shown a high amount of type IIa (15%), type Iab (20%) and type IaAB (65%) diamonds, the last type bearing high nitrogen aggregation. Cacoal, Espigão Dfoeste and Diamantina diamonds were classified as IaAB type showing variations in the nitrogen aggregate state. Ultraviolet analysis showed different fluorescence colors for each province caused by variable rare-earth elements concentrations... (Complete abstract, click electronic access below)
Descrição
Palavras-chave
Geologia economica, Diamantes, Caracterização de diamantes, Fotoluminescência, Kimberley Process Certification System, Diamonds
Como citar
FILEMON, Kelusodi Eduardo. Caracterização dos diamantes da província kimberlítica de Juína (MT), e distritos diamantíferos de Espigão D'Oeste (RO), Cacoal (RO) e Diamantina (MG). 2005. xv, 195 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Geociências e Ciências Exatas, 2005.