Low δ18O eclogites from the Kokchetav massif, northern Kazakhstan

H. Masago, D. Rumble, W. G. Ernst, C. D. Parkinson, S. Maruyama

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Oxygen isotopic compositions of silicates in eclogites and whiteschists from the Kokchetav massif were analyzed by whole-grain CO2-laser fluorination methods. Systematic analyses yield extremely low δ18O for eclogites, as low as -3.9‰ for garnet; these values are comparable with those reported for the Dabie-Sulu UHP eclogites. Oxygen isotopic compositions are heterogeneous in samples of eclogite, even on an outcrop scale. Schists have rather uniform oxygen isotope values compared to eclogites, and low δ18O is not observed. Isotope thermometry indicates that both eclogites and schists achieved high-temperature isotopic equilibration at 500 800 °C. This implies that retrograde metamorphic recrystallization barely modified the peak-metamorphic oxygen isotopic signatures. A possible geological environment to account for the low-δ18O basaltic protolith is a continental rift, most likely subjected to the conditions of a cold climate. After the basalt interacted with low δ18O meteoric water, it was tectonically inserted into the surrounding sedimentary units prior to, or during subduction and UHP metamorphism.

Original languageEnglish
Pages (from-to)579-587
Number of pages9
JournalJournal of Metamorphic Geology
Volume21
Issue number6
DOIs
Publication statusPublished - Aug 2003
Externally publishedYes

Fingerprint

Oxygen
oxygen
schist
isotopic composition
Oxygen Isotopes
laser method
Silicates
Fluorination
Garnets
eclogite
meteoric water
protolith
Chemical analysis
Isotopes
oxygen isotope
garnet
outcrop
metamorphism
subduction
silicate

Keywords

  • Eclogite
  • Kokchetav massif
  • Low δO
  • Whiteschist

ASJC Scopus subject areas

  • Geology

Cite this

Masago, H., Rumble, D., Ernst, W. G., Parkinson, C. D., & Maruyama, S. (2003). Low δ18O eclogites from the Kokchetav massif, northern Kazakhstan. Journal of Metamorphic Geology, 21(6), 579-587. https://doi.org/10.1046/j.1525-1314.2003.00465.x

Low δ18O eclogites from the Kokchetav massif, northern Kazakhstan. / Masago, H.; Rumble, D.; Ernst, W. G.; Parkinson, C. D.; Maruyama, S.

In: Journal of Metamorphic Geology, Vol. 21, No. 6, 08.2003, p. 579-587.

Research output: Contribution to journalArticle

Masago, H, Rumble, D, Ernst, WG, Parkinson, CD & Maruyama, S 2003, 'Low δ18O eclogites from the Kokchetav massif, northern Kazakhstan', Journal of Metamorphic Geology, vol. 21, no. 6, pp. 579-587. https://doi.org/10.1046/j.1525-1314.2003.00465.x
Masago, H. ; Rumble, D. ; Ernst, W. G. ; Parkinson, C. D. ; Maruyama, S. / Low δ18O eclogites from the Kokchetav massif, northern Kazakhstan. In: Journal of Metamorphic Geology. 2003 ; Vol. 21, No. 6. pp. 579-587.
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