Diamond growth rates and physical properties of laboratory-made diamond

Strong, H. M.; Chrenko, R. M.

doi:10.1021/j100681a014

Cited by 265 publications

(118 citation statements)

References 2 publications

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“…This could be interpreted as indicating inaccuracies in the methods used either in determining these PT estimates or in delimiting the geotherms. However, if the alternative diamond ~ graphite boundaries of Bundy et al (1961) and Strong and Chrenko (1971) are taken to be correct, then the PT estimates for all the diamond-bearing eclogites lie essentially within the diamond stability field. It may be fortuitous but it is none the less encouraging to note that the diamond-bearing eclogite which plots with lowest PT equilibration values on the geotherms (essentially at the intersection of the geotherms with the Bundy et al (1961) and Strong and Chrenko (1971) diamond~--graphite equilibrium boundaries) is nodule HRV 247 of Hatton and Gurney (1979) reported to contain coexisting primary diamond and graphite.…”

Section: Diamondiferous Eclogitesmentioning

confidence: 95%

“…The bar symbols in order of decreasing lengths signify Roberts Victor diamondbearing eclogites; Roberts Victor diamond-free eclogites; and Bellsbank area eclogites; respectively. The various diamond-graphite equilibrium boundaries are from (a) Strong and Chrenko (1971); (b) Bundy et al (1961); (c) Berman (1979); (d) Strong and Hanneman (1967); and (e) Kennedy andKennedy (1976). 1978).…”

Section: Implications For Geothermal Gradientsmentioning

confidence: 99%

“…Also shown in fig. 4 are boundaries (a) and (d) based on gross linear extrapolations of two different pairs of hightemperature equilibration points, experimentally determined by Strong and Chrenko (1971) and Strong and Hanneman (1967), resPectively; and boundary (c) which is the thermodynamically calculated boundary of Berman (1979). These various boundaries thus indicate that the degree of uncertainty over the precise location of the diamond graphite equilibrium boundary amounts to some 5 kb in pressure terms at the likely equilibration temperatures of these eclogite nodules.…”

Section: Diamondiferous Eclogitesmentioning

confidence: 99%

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Equilibration conditions of upper-mantle eclogites: implications for kyanite-bearing and diamondiferous varieties

1981

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ABSTRACT. New mineral data for kyanite-bearing eclogites supplement existing data for eclogite nodule suites from the Roberts Victor and Bellsbank kimberlite intrusions, South Africa. Calculation of equilibration temperatures using the refined KD calibration of Ellis and Green (1979) indicates that the majority of these eclogites equilibrated over a considerably narrower range (940-1185 ~ than implied by earlier estimates which did not take account of the influence of the Ca-component of garnet on K o. Most of the Roberts Victor diamondiferous eclogites appear to have equilibrated in the lower part of this range, whilst the equilibration temperatures for the Roberts Victor diamond-free eclogites extend to higher values than those from Bellsbank. The petrogenetic implications of the (calculated) temperature and pressure equilibration conditions for these eclogite suites are discussed with particular reference to possible uppermantle geotherms and available data on the graphitediamond transition boundary.

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Section: Diamondiferous Eclogitesmentioning

confidence: 95%

Section: Implications For Geothermal Gradientsmentioning

confidence: 99%

Section: Diamondiferous Eclogitesmentioning

confidence: 99%

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Equilibration conditions of upper-mantle eclogites: implications for kyanite-bearing and diamondiferous varieties

1981

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“…The number of diamond nucleation centers is rather small (10 −1 /mm 3 ), and the growth rate is ∼40 μm/h. Crystallization of these diamonds is associated with the appearance of a metal-carbon melt, which arises due to the existence of the metastable Fe-graphite eutectic (8,36). At the initial stages of the interaction, the iron is gradually saturated with carbon to form metal-carbon melt and carbide.…”

Section: Significancementioning

confidence: 99%

Mantle–slab interaction and redox mechanism of diamond formation

Palyanov

Bataleva

Sokol

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

176

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Subduction tectonics imposes an important role in the evolution of the interior of the Earth and its global carbon cycle; however, the mechanism of the mantle-slab interaction remains unclear. Here, we demonstrate the results of high-pressure redox-gradient experiments on the interactions between Mg-Ca-carbonate and metallic iron, modeling the processes at the mantle-slab boundary; thereby, we present mechanisms of diamond formation both ahead of and behind the redox front. It is determined that, at oxidized conditions, a low-temperature Ca-rich carbonate melt is generated. This melt acts as both the carbon source and crystallization medium for diamond, whereas at reduced conditions, diamond crystallizes only from the Fe-C melt. The redox mechanism revealed in this study is used to explain the contrasting heterogeneity of natural diamonds, as seen in the composition of inclusions, carbon isotopic composition, and nitrogen impurity content.carbonate-iron interaction | high-pressure experiment | mantle mineralogy | deep carbon cycle S ubduction of crustal material plays an important role in the global carbon cycle (1-6). Depending on oxygen fugacity and pressure-temperature (P-T) conditions, carbon exists in the Earth's interior in the form of carbides, diamond, graphite, hydrocarbons, carbonates, and CO 2 (7-11). In the upper mantle, the oxygen fugacity (fO 2 ) varies from one to five log units below the fayalitemagnetite-quartz (FMQ) buffer, with a trend of a decrease with depth (6,(12)(13)(14)(15). At a depth of ∼250 km, mantle is reported to become metal saturated (16, 17), which holds true for all mantle regions below, including the transition zone and lower mantle. The subduction of the oxidized crustal material occurs to depths greater than 600 km (4-6). The main carbon-bearing minerals of the subducted materials are carbonates, which are thermodynamically stable up to P-T conditions of the lower mantle (10,11,18). As evidenced by the compositions of inclusions in diamond, which vary from strongly reduced, e.g., metallic iron and carbides (19-23), to oxidized, e.g., carbonates and CO 2 (6,20,(24)(25)(26)(27)(28), carbonates may be involved in the reactions with reduced deep-seated rocks, including Fe 0 -bearing species (29-31). A scale of these reactions is determined mainly by the capacity of subducted carbonate-bearing domains. An important consequence of such an interaction is that it can produce diamond. However, studies on diamond synthesis via the reactions between oxidized and reduced phases are limited (32-35).To understand the mechanisms of the interaction of carbonbearing oxidized-and reduced-mineral assemblages, we performed high-pressure experiments with an iron-carbonate system; an approach was used that enabled the creation of an oxygen fugacity gradient in the capsules (Materials and Methods and SI Materials and Methods). Results and DiscussionThe experimental results and the phase compositions are given in Table 1 and Table S1, respectively. At temperatures of 1,000 and 1,100°C, the iron-car...

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“…However, B-diamond synthesized by a temperature gradient method at high pressure and high temperature (denoted by HPT) 20,21 has not been analyzed by XES and XAS yet. The difference between the CVD and HPT methods is the impurity nitrogen in the diamond matrix; CVD-diamond has a negligible nitrogen impurity, while HPT-diamond generally has ppm-or sub-ppm-orders of nitrogen as an impurity.…”

Section: Introductionmentioning

confidence: 99%