Experimental determination of the temperature and pressure dependence of the Fe-Mg partition coefficient for coexisting garnet and clinopyroxene

Råheim, A.; Green, David H.

doi:10.1007/bf00383355

Cited by 310 publications

(113 citation statements)

References 17 publications

Supporting

Mentioning

109

Contrasting

Order By: Relevance

“…P-T estimates for Kesandere eclogites using geothermobarometers (Bhattacharya et al, 1992;Krogh, 2000;Perchuk & Lavrent'eva, 1983;Råheim & Green, 1974) and comparison with values published for eclogites from Mt. Gablor (Okay et al, 1985) in the western Bitlis complex.…”

Section: Zircon U/pb Geochronology and Trace Element Compositionmentioning

confidence: 94%

“…Applying the classical geothermobarometric tools (Carswell & Harley, 1990;Krogh, 2000;Newton & Smith, 1967;Råheim & Green, 1974) on garnet-clinopyroxene pairs of well-preserved eclogite samples (Van 95), provide pressures ranging from 1.9 to 2.4 GPa and temperatures spanning 480-540°C (Figure 4). These P-T conditions are somewhat colder that those estimated by Okay et al (1985; 1.0-2.0 GPa/600-650°C) for metagabbroic eclogites of Mt.…”

Section: Petrologymentioning

confidence: 99%

See 1 more Smart Citation

Late Cretaceous eclogitic high-pressure relics in the Bitlis Massif

et al. 2013

View full text Add to dashboard Cite

A new occurrence of eclogites was found in the Kesandere valley in the eastern most part of the Bitlis complex, SE Anatolia. These high-pressure (HP) relics were preserved in calc-arenitic metasediments within the high-grade metamorphic basement of the Bitlis complex. The eclogitic parageneses were strongly overprinted during decompression and heating. These new eclogites locality complements the evidence of blueschist-facies metamorphism documented recently in the meta-sedimentary cover sequence of this part of the Bitlis complex. Thermodynamic calculations suggest peak conditions of ca. 480-540°C/1.9-2.4 GPa. New U/Pb dates of 84.4 ± .9 and 82.4 ± .9 Ma were obtained on zircons from two Kesandere eclogite samples. On the basis of geochemical criteria, these dates are interpreted to represent zircon crystallization during the eclogitic peak stage. Kesandere eclogites differ from those previously described in the western Bitlis complex (Mt. Gablor locality) in terms of lithologic association, protolithic origin, and peak P-T conditions (600-650°C/1.0-2.0 GPa, respectively). On the other hand, eclogitic metamorphism of Kesandere metasediments occurred shortly before blueschist-facies metamorphism of the sedimentary cover (79-74 Ma 40 Ar/ 39Ar white mica). Therefore, the exhumation of Kesandere eclogites started between ca. 82 and 79 Ma, while the meta-sedimentary cover was being buried. During this short time span, Kesandere eclogite were likely uplifted from~65 to 35 km depth, indicating a syn-subduction exhumation rate of~4.3 mm/a. Subsequently, eclogite-and blueschist-facies rocks were likely retrogressed contemporarily during collision-type metamorphism (around 72-69 Ma). The Bitlis HP rocks thus sample a subduction zone that separated the Bitlis-Pütürge (Bistun?) block from the South-Armenian block, further north. To the south, Eocene metasediments of the Urse formation are imbricated below the Bitlis complex. They contain (post Eocene) blueschists, testifying separation from the Arabian plate and southward migration of the subduction zone. The HT overprint of Kesandere eclogites can be related to the asthenospheric flow provoked by subducting slab retreat or break off.

show abstract

Section: Zircon U/pb Geochronology and Trace Element Compositionmentioning

confidence: 94%

Section: Petrologymentioning

confidence: 99%

Late Cretaceous eclogitic high-pressure relics in the Bitlis Massif

et al. 2013

View full text Add to dashboard Cite

show abstract

“…They include Fe Mg exchange reactions between garnet and clinopyroxene (Råheim and Green, 1974;Ellis and Green, 1979;Powell, 1985;Pattison and Newton, 1989) and those between garnet and hornblende (Graham and Powell, 1984) for geothermometers, and the net transfer reactions among garnet, clinopyroxene, plagioclase and quartz (Newton and Perkins, 1982) and among garnet, hornblende, plagioclase and quartz (Kohn and Spear, 1990) for geobarometers. The ferric contents of garnet, clinopyroxene and hornblende are negligible, as described above, therefore all the calculations were performed with ferric free compositions.…”

Section: Geothermobarometrymentioning

confidence: 99%

“…Abbreviations: EG79, Ellis and Green (1979); GP84, Graham and Powell (1984); KS90Fe, Fe endmember reaction of Kohn and Spear (1990); KS90Mg, Mg endmember reaction of Kohn and Spear (1990); NP82, Newton and Perkins (1982); P85, Powell (1985); PN89, Pattison and Newton (1989); RG75, Råheim and Green (1974). Solid circles, shaded circles and open circles represent P T conditions, as summarized by Pattison (2003), for garnet clinopyroxene plagioclase rocks (with or without hornblende and quartz) of the granulite facies, for those in the transition between the granulite and amphibolite facies, and for those of the amphibolite facies, respectively.…”

Section: Gap In Metamorphic Grade Between the Mylonite Unit And The Cmentioning

confidence: 99%

Garnet-clinopyroxene amphibolite from the Takahama metamorphic rocks, western Kyushu, SW Japan: evidence for high-pressure granulite facies metamorphism

Ikeda

Yoshida

Arima

et al. 2005

Journal of Mineralogical and Petrological Sciences

View full text Add to dashboard Cite

Garnet clinopyroxene amphibolites occur in the mylonite unit structurally at the top of the Takahama metamorphic rocks a member of the Nagasaki Metamorphic Rocks, western Kyushu, SW Japan. Geothermobarometry applied to an equigranular garnet clinopyroxene amphibolite, which escaped severe mylonitization, yields the metamorphic condition of 770 ± 70°C and 1.1 ± 0.2 GPa. This condition is comparable with the high pressure granulite facies, and is much higher grade than those of the underlying crystalline schists of the Takahama metamorphic rocks that belong to the epidote glaucophane schist subfacies. Despite the presence of such a gap in metamorphic condition between the crystalline schists and the mylonite unit, nearly identical muscovite K Ar ages have been obtained from these units, which indicate that both units were juxtaposed at depth before they cooled below the closure temperature of the muscovite K Ar system.

show abstract

“…In addition, the early isotopic composition of both clinopyroxene and garnet may have been modified by large-scale transport of H 2 O provided by the adjacent, dehydrating metapelites during the late lowerpressure metamorphic event marked by the hydration of the mafic eclogites to amphibolites (Heinrich 1982). CONCLUDING REMARKS Bocchio et al (1985) applied the classical geothermometers of Råheim & Green (1974) and Ellis & Green (1979) based on the partition of Fe 2+ and Mg between coexisting garnet and clinopyroxene and obtained a temperature of equilibration of 480°C for the eclogite 70-AM-10, which is lower than that reported in the literature for other samples in the area. They noted that this unrealistic value derives from the extremely low Fe 2+ content of the clinopyroxene, although this mineral, on the whole, is not unusual in any other respect.…”

mentioning

confidence: 99%

New Chemical Data on the Clinopyroxene-Garnet Pair in the Alpe Arami Eclogite, Central Alps, Switzerland

Bocchio

Capitani

Ottolini

2004

The Canadian Mineralogist

View full text Add to dashboard Cite

In the area of Gorduno, near Bellinzona, Central Alps, Switzerland, well-preserved eclogites crop out only at the margin of the garnet peridotite massif of Alpe Arami (AA). These bodies of eclogite were not derived from cognate mafic layers of mantle origin, and their thermal evolution is different from that inferred for the peridotite. Some questions are still open about the P-T evolution of AA eclogites, and the data given in literature cover a broad range of variation. We have investigated the bulk composition and the clinopyroxene-garnet trace-element distribution in a sample of eclogite from a lens occurring at the rim of the peridotite body. We report new data on trace elements in the bulk rock, obtained by ICP-MS, as well as the results of SIMS analyses on REE, Ti, V, Cr, Y, Sr, Zr, Sc carried out on the two major rock-forming minerals, i.e., clinopyroxene and garnet. We also provide AAS data for Co, Ni and Cu in purified clinopyroxene and garnet concentrates, and O isotope ratios both on the bulk rock and on clinopyroxene and garnet. We found that: i) the trace-element abundance in garnet and clinopyroxene may be strongly influenced by the major-element composition; ii) their distribution within both mineral phases is inhomogeneous. In particular, their highly variable contents highlight the complex evolution of the AA eclogite and emphasize the existence, at least for some elements and at a very local scale, of chemical disequilibrium, also confirmed, in an independent way, by a significant difference in ␦ 18O between clinopyroxene and garnet. Therefore, the low temperature of equilibration estimated in eclogite sample 70-AM-10 is not an artifact of the computational strategy adopted, but is the record of the lack of complete equilibration between clinopyroxene and garnet with changing P-T conditions during the various metamorphic events.Keywords: eclogite, garnet, clinopyroxene, SIMS data, trace elements, oxygen isotope data, Alpe Arami, Central Alps, Switzerland. SOMMAIREDes éclogites bien préservées affleurent dans la région de Gorduno, près de Bellinzona, Alpes centrales, en Suisse, mais seulement le long de la bordure du massif de Alpe Arami (AA) à péridotite grenatifère. Ces affleurements d'éclogite n'ont pas une dérivation par transformation de niveaux mafiques génétiquement liés à la péridotite dans le manteau, et leur évolution thermique diffère donc de celle déduite pour la péridotite. Certaines questions demeurent posées à propos de l'évolution P-T des éclogites de ce massif, et les données publiées font preuve d'une grande variabilité. Nous avons donc étudié la composition globale de ces roches et la distribution d'éléments traces entre les deux minéraux principaux, clinopyroxène et grenat, dans un échantillon d'éclogite provenant d'une lentille en bordure du massif péridotitique. Nos résultats portent sur la quantité des éléments traces dans la roche même, telles qu'indiquée par la méthode ICP-MS, de même que par analyses SIMS du clinopyroxène et du grenat portant sur les terres rar...

show abstract

Experimental determination of the temperature and pressure dependence of the Fe-Mg partition coefficient for coexisting garnet and clinopyroxene

Cited by 310 publications

References 17 publications

Late Cretaceous eclogitic high-pressure relics in the Bitlis Massif

Late Cretaceous eclogitic high-pressure relics in the Bitlis Massif

Garnet-clinopyroxene amphibolite from the Takahama metamorphic rocks, western Kyushu, SW Japan: evidence for high-pressure granulite facies metamorphism

New Chemical Data on the Clinopyroxene-Garnet Pair in the Alpe Arami Eclogite, Central Alps, Switzerland

Contact Info

Product

Resources

About