Ni in chrome pyrope garnets: a new geothermometer

Griffin, William L.; Cousens, D.R.; Ryan, C.G.; Sie, S.H.; Suter, G.F.

doi:10.1007/bf00378505

Cited by 141 publications

(39 citation statements)

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“…The mean value, ignoring the highest and lowest values, is 1182°C. This is approximately 75°C lower than the mean temperature of 13 clinopyroxene-garnet pairs from Argyle, calculated in the same way (Griffin et al 1989). Whereas we were unable to determine the trace-element patterns of the coexisting phases because of grain-size constraints, the overall pattern of relative abundances of elements in the garnet and clinopyroxene can give an indication of relative temperature.…”

Section: The Eclogitic Paragnesismentioning

confidence: 57%

“…These include: (1) (2) very high mean temperatures of diamond formation, (3) high levels of Ti and Na in garnet, and Ti and K in clinopyroxene included in diamond (Jaques et al 1989, Griffin et al 1989. The association of both deposits with magmas that intruded Proterozoic cratons, rather than typically Archean cratons, within a relatively short time (<1 Ga) after the last major tectonothermal event, may be significant.…”

Section: Discussionmentioning

confidence: 99%

“…Whereas we were unable to determine the trace-element patterns of the coexisting phases because of grain-size constraints, the overall pattern of relative abundances of elements in the garnet and clinopyroxene can give an indication of relative temperature. Griffin et al (1989) showed that the value of D Zr cpx/grt decreases with increasing T, whereas D Ga cpx/grt increases. The clinopyroxene inclusions of the Guaniamo suite have generally higher Zr than those of the Argyle suite, whereas the garnet inclusions have lower Zr contents than the corresponding garnet at Argyle.…”

Section: The Eclogitic Paragnesismentioning

confidence: 98%

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Diamond From the Guaniamo Area, Venezuela

Kaminsky

Zakharchenko

Griffin

et al. 2000

The Canadian Mineralogist

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More than 5,000 diamond crystals (or fragments) from kimberlite sills and placer deposits in the Guaniamo area of Venezuela have been characterized in terms of morphology, internal structure, carbon isotopic composition, syngenetic mineral inclusions, and the abundance and aggregation state of nitrogen. Ours is the first comprehensive mineralogical study of diamond from the Guaniamo area. About 50% of the crystals are resorbed dodecahedral forms; octahedra are the next most common form. In most cases, the diamond is colorless; 55-90% show radiation-induced pigmentation. About 20% of the stones have very low N contents (Type II); the remainder belong to the transitional IaAB type, with B > A. Ninety-three mineral inclusions were extracted from 77 crystals or fragments of diamond and analyzed by electron microprobe and LAM-ICP-MS to establish their traceelement compositions and the pressures and temperatures of diamond crystallization. In all, 86% of the diamond samples contain inclusions of the eclogitic paragenesis, represented by garnet, omphacite, rutile, ilmenite, pyrrhotite, and probable coesite. Inclusions indicative of the peridotite paragenesis are pyrope, chromian spinel and olivine. One inclusion of ferroan periclase may indicate a lower-mantle origin. The ␦ 13 C of 108 diamond samples ranges from -3.2‰ to -28.7‰, but most stones have ␦ 13 C ≤10‰. We contend that in large part, the diamond in placers in the Guaniamo area was derived from the Guaniamo kimberlite sills. P-T estimates on mineral inclusions suggest that most originated near the base of the lithosphere (T 1200-1300°C); this zone may contain a substantial proportion of eclogite formed by subduction of crustal material. The very high proportion of diamond derived from an eclogitic association in the Guaniamo deposits, and several features of the mineral inclusions trapped in diamond, show striking parallels to the Argyle deposit of Australia. Both deposits occur within cratons that have experienced extensive Proterozoic tectonothermal activity.Keywords: diamond, carbon isotope, nitrogen, mineral inclusions, eclogitic association, Guaniamo, Venezuela. SOMMAIRENous avons caractérisé plus de 5,000 cristaux (ou fragments) de diamant provenant de filons-couches de kimberlite et de dépôts alluvionnaires dans la région de Guaniamo, au Vénézuela, selon leur morphologie, leur structure interne, la composition isotopique du carbone, leurs inclusions minérales syngénétiques, et l'abondance et l'état d'agrégation de l'azote. Ce travail * Publication No. 213 of the ARC National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC). § E-mail address: felixvkaminsky@cs.com 1348 THE CANADIAN MINERALOGIST constitue la première étude minéralogique compréhensive du diamant de la région de Guaniamo. Environ 50% des cristaux ont une forme dodécaédrique résorbée; l'octaèdre est la deuxième forme la plus courante. Dans la plupart des cas, le diamant est incolore; entre 55 et 90% des échantillons font preuve d'une pigmentation due à une i...

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Section: The Eclogitic Paragnesismentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: The Eclogitic Paragnesismentioning

confidence: 98%

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Diamond From the Guaniamo Area, Venezuela

Kaminsky

Zakharchenko

Griffin

et al. 2000

The Canadian Mineralogist

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“…The CaO contents tend to be positively correlated with TiO 2 and those with the highest Ti and Ca straddle the harzburgite-lherzolite boundary. The depth of derivation of the garnet xenocrysts was obtained by projecting the averaged temperatures of the Ni-in-garnet thermometers of Griffin et al (1989) and Canil (1999) onto the local geothermal gradients for each locality (Fig. A2).…”

Section: Major Elements and Geothermobarometrymentioning

confidence: 99%

Ancient mantle metasomatism recorded in subcalcic garnet xenocrysts: Temporal links between mantle metasomatism, diamond growth and crustal tectonomagmatism

Shu

Brey

2015

Earth and Planetary Science Letters

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“…The garnets were classified based on their major element composition into harzburgitic (G10), lherzolitic (G9), wehrlitic (G12), high-Ti peridotitic (G11), lowCr megacrystal (G1), eclogitic (G3, G4), pyroxenitic (G4, G5), and crustal varieties according to Grütter et al (2004). For equilibration temperatures the Ni thermometer (Griffin et al, 1989a) was applied using the calibration of Ryan et al (1996). Equilibration pressures and temperatures of peridotitic clinopyroxene were calculated using the single-grain cpx thermobarometer of Nimis & Taylor (2000).…”

Section: Analytical Techniquesmentioning

confidence: 99%

Mantle transect of the Karelian Craton from margin to core based on P-T data from garnet and clinopyroxene xenocrysts in kimberlites

Lehtonen¹,

O’Brien²

2009

Bull Geol Soc Finland

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Peridotitic garnet and clinopyroxene xenocrysts from the 1.2 Ga Lentiira-Kuhmo and the 760 Ma Kuusamo kimberlite fields, emplaced within the Central Karelian Craton, have been studied using major and trace element geochemistry to obtain information on the stratigraphy, compositional variability, and evolutionary history of the underlying lithospheric mantle. An earlier study on the 600 Ma Kaavi-Kuopio kimberlite field showed that near the SW margin of the craton the 230-km-thick subcontinental lithospheric mantle (SCLM) exhibits a well-developed 3-layer structure indicative of episodic construction.

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Ni in chrome pyrope garnets: a new geothermometer

Cited by 141 publications

References 10 publications

Diamond From the Guaniamo Area, Venezuela

Diamond From the Guaniamo Area, Venezuela

Ancient mantle metasomatism recorded in subcalcic garnet xenocrysts: Temporal links between mantle metasomatism, diamond growth and crustal tectonomagmatism

Mantle transect of the Karelian Craton from margin to core based on P-T data from garnet and clinopyroxene xenocrysts in kimberlites

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