Luminescence of diamonds from metamorphic rocks

Bruce, Loryn F.; Kopylova, Maya G.; Longo, M.; Ryder, John; Dobrzhinetskaya, L.

doi:10.2138/am.2011.3467

Cited by 22 publications

(18 citation statements)

References 34 publications

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“…cubo-octahedral core growth structure, followed by octahedral zonation (Ju5-115); e blocky octahedral core followed by regular octahedral zonation with rounded resorbed corners and uneven colours of CL inside of the single zones (Ju5-71); and f macled octahedron with blocky irregular internal structure and plastic deformation Alongside the variety of internal structures, the variation in CL response colour has also been documented. All samples are a deep blue colour throughout their core regions (supplementary Figure 1), which is usually explained by the presence of N3-aggregated nitrogen centres (Bruce et al 2011). The rims of many samples have a bright green CL colour.…”

Section: Internal Diamond Morphologymentioning

confidence: 98%

Origin of sub-lithospheric diamonds from the Juina-5 kimberlite (Brazil): constraints from carbon isotopes and inclusion compositions

Thomson

Kohn²,

Bulanova

et al. 2014

Contrib Mineral Petrol

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interpreted as evidence of diamond growth from abiotic organic carbon added to the oceanic crust during hydrothermal alteration. The bulk isotopic composition of the oceanic crust, carbonates plus organics, is equal to the composition of mantle carbon (−5 ‰), and we suggest that recycling/mixing of subducted material will replenish this reservoir over geological time. Several exposed, syngenetic inclusions have bulk compositions consistent with former eclogitic magnesium silicate perovskite, calcium silicate perovskite and NAL or CF phases that have reequilibrated during their exhumation to the surface. There are multiple occurrences of majoritic garnet with pyroxene exsolution, coesite with and without kyanite exsolution, clinopyroxene, Fe or Fe-carbide and sulphide minerals alongside single occurrences of olivine and ferropericlase. As a group, the inclusions have eclogitic affinity and provide evidence for diamond formation at pressures extending to Earth's deep transition zone and possibly the lower mantle. It is observed that the major element composition of inclusions and isotopic compositions of host Juina-5 diamonds are not correlated. The diamond and inclusion compositions are intimately related to subducted material and record a polybaric growth history across a depth interval stretching from the lower mantle to the base of the lithosphere. It is suggested that the interaction of slabderived melts and mantle material combined with subsequent upward transport in channelised networks or a buoyant diapir explains the formation of Juina-5 diamonds. We conclude that these samples, despite originating at great mantle depths, do not provide direct information about the ambient mantle, instead, providing a snapshot of the Earth's deep carbon cycle. Keywords Diamonds · Sub-lithospheric mantle · Carbon cycle · SubductionAbstract Forty-one diamonds sourced from the Juina-5 kimberlite pipe in Southern Brazil, which contain optically identifiable inclusions, have been studied using an integrated approach. The diamonds contain <20 ppm nitrogen (N) that is fully aggregated as B centres. Internal structures in several diamonds revealed using cathodoluminescence (CL) are unlike those normally observed in lithospheric samples. The majority of the diamonds are composed of isotopically light carbon, and the collection has a unimodal distribution heavily skewed towards δ 13 C ~ −25 ‰. Individual diamonds can display large carbon isotope heterogeneity of up to ~15 ‰ and predominantly have isotopically lighter cores displaying blue CL, and heavier rims with green CL. The light carbon isotopic compositions are Communicated by O. Müntener. Electronic supplementary materialThe online version of this article

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Section: Internal Diamond Morphologymentioning

confidence: 98%

Origin of sub-lithospheric diamonds from the Juina-5 kimberlite (Brazil): constraints from carbon isotopes and inclusion compositions

Thomson

Kohn²,

Bulanova

et al. 2014

Contrib Mineral Petrol

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“…3b, c and 4). Blue CL colors for diamond are due to the naturally occurring N3 color center and typical for diamonds that have not experienced significant metamorphism (Bruce et al, 2011). Diamonds commonly display resorbed edges and plastic deformation.…”

Section: Jde a Diamondsmentioning

confidence: 99%

Diamond growth from oxidized carbon sources beneath the Northern Slave Craton, Canada: A δ13C–N study of eclogite-hosted diamonds from the Jericho kimberlite

Smart

Chacko

Stachel

et al. 2011

Geochimica et Cosmochimica Acta

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“…Nevertheless, the particular sensitivity of the PL technique not only presents information on the emission colors and the defect distribution in different domains of the crystal, but also offers the possibility to record narrow peaks and electron-vibrational systems in the PL spectra gathering emittance over the entire volume of stone at low temperatures. PL spectra are widely used to characterize the collections of natural diamonds from different localities and to identify their colors (Nadolinny et al 2009b;Iakoubovskii and Adriaenssens 2002;Yang et al 2012;Bruce et al 2011;Tretiakova 2009;De Weerdt and Collins 2007;Gaillou et al 2010;Deljanin et al 2008). Electron paramagnetic resonance (EPR) is a valuable method to determine the defect structure.…”

Section: Introductionmentioning

confidence: 99%

The characteristic photoluminescence and EPR features of superdeep diamonds (São-Luis, Brazil)

et al. 2015

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Luminescence of diamonds from metamorphic rocks

Cited by 22 publications

References 34 publications

Origin of sub-lithospheric diamonds from the Juina-5 kimberlite (Brazil): constraints from carbon isotopes and inclusion compositions

Origin of sub-lithospheric diamonds from the Juina-5 kimberlite (Brazil): constraints from carbon isotopes and inclusion compositions

Diamond growth from oxidized carbon sources beneath the Northern Slave Craton, Canada: A δ13C–N study of eclogite-hosted diamonds from the Jericho kimberlite

The characteristic photoluminescence and EPR features of superdeep diamonds (São-Luis, Brazil)

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