Solid molecular nitrogen (δ-N2) inclusions in Juina diamonds: Exsolution at the base of the transition zone

Navon, O.; Wirth, Richard; Schmidt, Christian; Jablon, B.M.; Schreiber, Anja; Emmanuel, Simon

doi:10.1016/j.epsl.2017.01.035

Cited by 35 publications

(38 citation statements)

References 61 publications

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“…2b, similar to the approach in references (19,20). Right away it is clear that these pressure-temperature paths have rather steep slopes ∆T/∆P and that any possible intersection occurs within the stability field of fluid H2O rather than ice-VII (Fig.…”

Section: Estimation Of Entrapment Pressuresmentioning

confidence: 55%

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Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle

Tschauner

Huang

Greenberg

et al. 2018

Science

184

139

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Encapsulating Earth's deep water filter Small inclusions in diamonds brought up from the mantle provide valuable clues to the mineralogy and chemistry of parts of Earth that we cannot otherwise sample. Tschauner et al. found inclusions of the high-pressure form of water called ice-VII in diamonds sourced from between 410 and 660 km depth, the part of the mantle known as the transition zone. The transition zone is a region where the stable minerals have high water storage capacity. The inclusions suggest that local aqueous pockets form at the transition zone boundary owing to the release of chemically bound water as rock cycles in and out of this region. Science , this issue p. 1136

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Section: Estimation Of Entrapment Pressuresmentioning

confidence: 55%

“…One method is based on the low compressibility and thermal expansion of diamond and assumes that the current residual pressure of the inclusion and the pressure and temperature of its entrapment are connected through a path that is close to an isochore (19,20).The other method is based on isomekes (33).…”

Section: Estimation Of Entrapment Pressuresmentioning

confidence: 99%

Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle

Tschauner

Huang

Greenberg

et al. 2018

Science

184

139

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“…The three diamonds we studied are unique in their very high nitrogen content and in the way in which their depth of origin was determined. Navon et al (2017) detected 100% of B centers and only negligible contribution from platelets that were probably degraded, making them highly irregular diamonds (Woods 1986). Transmission electron microcopy (TEM) revealed the presence of nanometric inclusions of bimodal size distribution (~200 nm and ~20 nm).…”

Section: Introductionmentioning

confidence: 99%

“…Transmission electron microcopy (TEM) revealed the presence of nanometric inclusions of bimodal size distribution (~200 nm and ~20 nm). Navon et al (2017) used Raman spectroscopy to identify the content of these inclusions as -N2, a high-pressure polymorph of molecular nitrogen, and calculated an internal pressure of 10.9±0.5 GPa based on the shift of the Raman lines. Using the phase diagram and the equations of state of fluid N2 and diamond, they estimated the internal pressure at mantle temperatures (along a geotherm) and suggested that the inclusions were formed at ~22 GPa, corresponding to depth of more than 600 km and temperatures of more than 1600°C, at the base of the transition zone.…”

Section: Introductionmentioning

confidence: 99%

“…They suggested that the nanometric inclusions were formed by exsolution of nitrogen that resided in platelets and B centers as the diamond descended into the base of the transition zone in a down-going convecting mantle current. Navon et al (2017) estimated that the diamonds carry ~900 ppm nitrogen in B centers and an additional 500 ppm of -N2 in the zones populated by the exsolutions.…”

Section: Introductionmentioning

confidence: 99%

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Carbon and nitrogen systematics in nitrogen-rich, ultradeep diamonds from Sao Luiz, Brazil

et al. 2018

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Three diamonds from Sao Luiz, Brazil carrying nano-and micro-inclusions of molecular δ-N2 that exsolved at the base of the transition zone were studied for their carbon and nitrogen isotopic composition and the concentration of nitrogen utilizing SIMS. The diamonds are individually uniform in their carbon isotopic composition and most spot analyses yield δ 13 C values of-3.2±0.1‰ (ON-SLZ-390) and-4.7±0.1‰ (ON-SLZ-391 and 392). Only a few analyses deviate from these tight ranges and all fall within the main mantle range of-5±3‰. Most of the nitrogen isotope analyses also have typical mantle δ 15 N values (-6.6±0.4‰,-3.6±0.5‰ and-4.1±0.6‰ for ON-SLZ-390, 391 and 392, respectively) and are associated with high nitrogen concentrations of 800-1250 atomic ppm. However, some nitrogen isotopic ratios, associated with low nitrogen concentrations (<400 ppm) and narrow Manuscript Click here to download Manuscript Navon et al Carbon and nitrogen systematics in TZ diamonds.docx zones with bright luminescence are distinctly above the average, reaching positive  15 N values. These sharp fluctuations can neither be attributed to fractionation nor are they easily explained by introduction of new pulses of melt or fluid. We discuss the possibility that they result from fractionation between different growth directions, so that distinct  15 N values and nitrogen concentrations may form during diamond growth from a single melt/fluid. Other more continuous variations, in the core of ON-SLZ-390 or the rim of ON-SLZ-392 may be the result of Rayleigh fractionation or mixing.

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High‐Pressure Carbonaceous Phases as Minerals

Tschauner

2020

Geophysical Monograph Series

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High-pressure carbonaceous minerals establish a link between one of the most abundant chemical elements and processes that occur at high pressures, either in the interior of the Earth or during shock-metamorphosis in space or on Earth. Diamonds from the Earth's mantle carry inclusions of carbides, carbonates, methane, and carbon-dioxide. These inclusions elucidate diamond formation and the carbon recycling in the mantle. This chapter focuses on these inclusion minerals themselves, the means of detection, and the reconstruction of pressure-temperature conditions of their formation in the mantle.

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Solid molecular nitrogen (δ-N2) inclusions in Juina diamonds: Exsolution at the base of the transition zone

Cited by 35 publications

References 61 publications

Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle

Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle

Carbon and nitrogen systematics in nitrogen-rich, ultradeep diamonds from Sao Luiz, Brazil

High‐Pressure Carbonaceous Phases as Minerals

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