Mineralogical characterization of diamonds from Roosevelt Indigenous Reserve, Brazil, using non-destructive methods

Borges, Mariana Prado; Moura, Márcia Abrahão; Lenharo, S L R; Smith, C. B.; Araújo, Doralúcia Pedrosa de

doi:10.1016/j.lithos.2016.08.003

“…Essa reserva indígena foi homologada em 1991 e ocupa uma área de 2,6 milhões de hectares entre os estados de Rondônia e de Mato Grosso (BRASIL 1991). A TI Roosevelt está inserida dentro de um complexo kimberlítico com 54 corpos identificados (Figura 1) (BORGES et al 2016, que segundo apontamentos, constitui uma das dez maiores reservas de diamantes do mundo, com capacidade para produzir, no mínimo, um milhão de quilates por ano, o que representaria uma receita anual de US$ 200 milhões (MAPA DE CONFLITOS 2013).…”

Section: Diamantes Ilegais: Externalidades Social Econômica E Ambientalunclassified

“…Nos últimos anos, os avanços científicos para determinação da filiação dos minerais e identificação de suas fontes a partir dos métodos científicos, embora ainda insuficiente para identificação de um cristal individual, disponibiliza métodos e crité-rios para a identificação coletiva de minerais. Os principais métodos se baseiam no footprinting e no fingerprinting (BORGES et al 2016). A primeira analisa o diamante a partir de características geomorfológicas, enquanto a segunda se baseia em sua identidade química.…”

Section: O Pilar Central Da Certificação Kimberley: Traçando As Orige...unclassified

“…No Brasil, avanços nesse sentido existem e já permitem, com alguma restrição, lançar mão de critérios para a identificação da origem de certos diamantes nacionais e auxiliar na emissão de certificações dessas áreas (e.g. CHAVES & BENITZ 2006, BENITEZ 2009, BORGES et al 2016 Ainda que com o aperfeiçoamento contínuo dessas técnicas, suas eficácias e relevâncias dependem de um banco de dados confiável que contenha informações estatisticamente válidas de cada área produtora. No entanto, esses métodos se destacam como promissores e de extrema relevância, como uma ferramenta adicional na busca do reconhecimento da origem dos diamantes, seja ele certificado, "de sangue" ou "de tribo".…”

Section: O Pilar Central Da Certificação Kimberley: Traçando As Orige...unclassified

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Aspectos econômicos de certificações em diamantes: 20 anos da Certificação Kimberley no Brasil

Pinheiro¹,

Vasconcelos²

2022

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A Certificação Kimberley (CPK) é um instrumento internacional que atesta a origem dos diamantes naturais, buscando coibir seu comércio quando proveniente de áreas de conflitos, e regulamentar seu mercado internacional. Instituído pela ONU em 2002, atualmente o CPK agrega 82 países signatários que respondem pela produção global de 99,8%. O Brasil aderiu ao CPK em 2003 e, embora inexpressivo na produção mundial de diamantes, destaca-se como um dos países membros mais singulares, tanto pelo estilo de seus depósitos, em sua maioria secundários, quanto pela estruturação de sua cadeia e estrutura de produção, que influenciam diretamente na dinâmica de seu mercado, nas certificações nacionais e nos propósitos do CPK no país. Este trabalho apresenta as idiossincrasias brasileiras junto a seus pares no CPK e analisa a cadeia de produção nacional, tanto em períodos antecessores, quanto aos posteriores ao ingresso do país no CPK.

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“…Despite the area's significance, publications about peridotitic, pyroxenitic and/ or eclogitic mantle xenoliths are scarce, primarily those using modern analytical techniques. Compositional data coupled with pressure and temperature calculations from garnet peridotite and eclogite samples from Rondônia and Mato Grosso states, are present in some unpublished academic thesis and dissertations (e.g., Costa 1996;Costa 2013;Weska and Svisero 2001;Nannini 2015;Cabral Neto et al 2017a), whereas significant international publications are restricted to the study of diamonds derived from the lithospheric and sublithospheric mantle (e.g., Kaminsky et al 2010;Pearson et al 2014b;Hunt et al 2009;Thomson et al 2016;Borges et al 2016;Rudloff-Grund et al 2016;Navon et al 2017). Mantle xenoliths hosted by kimberlites and kamafugites are otherwise more reported in papers from the APIP (Meyer and Svisero 1991;Leonardos et al 1993;Carlson et al 2007;Almeida et al 2014;Nannini 2015;Fernandes et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

Almeida¹,

Rodrigues²,

Neto³

et al. 2022

JGSB

0

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We present new petrographic and chemical data together with calculated P-T equilibrium conditions of peridotite xenoliths enclosed in kimberlites from Rondônia, Northern Brazil (Cosmos-1 and Carolina-1) and Minas Gerais, Southeastern Brazil (Canastra-1) located in the Azimuth 125º Lineament. The composition of the mantle minerals is distinct in both areas, which can be related to the diversity of the lithospheric mantle beneath the southwestern portion of the Amazonian Craton and the Brasília Belt. New and compiled chemical data indicate that subcalcic G10 garnet occurs in samples from the Canastra-1 kimberlite and other occurrences of the Alto Paranaíba Igneous Province and can be related to the remnants of the Archean lithospheric mantle of the São Francisco Craton beneath the area. The garnets from Rondônia are mostly G5 (pyroxenitic) and G9 (lherzolitic) with a higher abundance of G3 (eclogitic) and G4 (pyroxenitic/eclogitic) relative to the Alto Paranaíba Igneous Province. Higher pressures and temperatures were calculated for the samples from Rondônia (40-60 kbar and 1030-1380 ºC) compared to samples from Minas Gerais (25-40 kbar and 730-1000 ºC). The peridotite xenoliths from Rondônia show P-T equilibrium conditions in the diamond stability field and can be the source of at least part of the diamond from the area. The P-T stability fields of the xenoliths from both locations are aligned close to the 40 mW/m2 geotherm. The data indicate that the cratonic 40 mW/m2 geothermal gradient in Rondônia may be related to a process of thermal relaxation of the lithospheric mantle after the Paleoproterozoic to Mesoproterozoic tectonothermal events of the southwestern Amazonian Craton until the sampling of the xenoliths by the magma in the Permian-Triassic.Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites Accepted manuscript -Uncorrected pre-proof This is a PDF file containing an unedited and non-definitive version of a manuscript that has been accepted for publication by the Journal of the Geological Survey of Brazil -JGSB, which serves to provide early visibility of the article. Being an uncorrected preproof version, errors may appear during the production process (language review, formatting and proof review), and these can affect the final content of the article and all legal disclaimers (https://jgsb.cprm.gov.br/index.php/journal/6).

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“…Despite the area's significance, publications about peridotitic, pyroxenitic and/ or eclogitic mantle xenoliths are scarce, primarily those using modern analytical techniques. Compositional data coupled with pressure and temperature calculations from garnet peridotite and eclogite samples from Rondônia and Mato Grosso states, are present in some unpublished academic thesis and dissertations (e.g., Costa 1996;Costa 2013;Weska and Svisero 2001;Nannini 2015;Cabral Neto et al 2017a), whereas significant international publications are restricted to the study of diamonds derived from the lithospheric and sublithospheric mantle (e.g., Kaminsky et al 2010;Pearson et al 2014b;Hunt et al 2009;Thomson et al 2016;Borges et al 2016;Rudloff-Grund et al 2016;Navon et al 2017). Mantle xenoliths hosted by kimberlites and kamafugites are otherwise more reported in papers from the APIP (Meyer and Svisero 1991;Leonardos et al 1993;Carlson et al 2007;Almeida et al 2014;Nannini 2015;Fernandes et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southeastern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

Almeida¹,

Rodrigues²,

Neto³

et al. 2022

JGSB

2

0

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We present new petrographic and chemical data together with calculated P-T equilibrium conditions of peridotite xenoliths enclosed in kimberlites from Rondônia, Northern Brazil (Cosmos-1 and Carolina-1) and Minas Gerais, Southeastern Brazil (Canastra-1) located in the Azimuth 125º Lineament. The composition of the mantle minerals is distinct in both areas, which can be related to the diversity of the lithospheric mantle beneath the southwestern portion of the Amazonian Craton and the Brasília Belt. New and compiled chemical data indicate that subcalcic G10 garnet occurs in samples from the Canastra-1 kimberlite and other occurrences of the Alto Paranaíba Igneous Province and can be related to the remnants of the Archean lithospheric mantle of the São Francisco Craton beneath the area. The garnets from Rondônia are mostly G5 (pyroxenitic) and G9 (lherzolitic) with a higher abundance of G3 (eclogitic) and G4 (pyroxenitic/eclogitic) relative to the Alto Paranaíba Igneous Province. Higher pressures and temperatures were calculated for the samples from Rondônia (40-60 kbar and 1030-1380 ºC) compared to samples from Minas Gerais (25-40 kbar and 730-1000 ºC). The peridotite xenoliths from Rondônia show P-T equilibrium conditions in the diamond stability field and can be the source of at least part of the diamond from the area. The P-T stability fields of the xenoliths from both locations are aligned close to the 40 mW/m2 geotherm. The data indicate that the cratonic 40 mW/m2 geothermal gradient in Rondônia may be related to a process of thermal relaxation of the lithospheric mantle after the Paleoproterozoic to Mesoproterozoic tectonothermal events of the southwestern Amazonian Craton until the sampling of the xenoliths by the magma in the Permian-Triassic.Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites Accepted manuscript -Uncorrected pre-proof This is a PDF file containing an unedited and non-definitive version of a manuscript that has been accepted for publication by the Journal of the Geological Survey of Brazil -JGSB, which serves to provide early visibility of the article. Being an uncorrected preproof version, errors may appear during the production process (language review, formatting and proof review), and these can affect the final content of the article and all legal disclaimers (https://jgsb.cprm.gov.br/index.php/journal/6).

show abstract

Mineralogical characterization of diamonds from Roosevelt Indigenous Reserve, Brazil, using non-destructive methods

Cited by 6 publications

References 47 publications

Aspectos econômicos de certificações em diamantes: 20 anos da Certificação Kimberley no Brasil

Aspectos econômicos de certificações em diamantes: 20 anos da Certificação Kimberley no Brasil

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

Composition and P-T conditions of the lithospheric mantle beneath the Azimuth 125º Lineament, Northern and Southeastern Brazil: constraints from peridotite xenoliths enclosed in diamond-bearing kimberlites

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