Reaction texture and Fe-Mg zoning in granulite garnet from Søstrene Island, Antarctica: Modeling and constraint on the time scale of metamorphism during the Pan-African collisional event

Jibamitra Ganguly, B. J. Hensen, W. Cheng

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Garnets from the Søtrene island, Antarctica, show reaction textures corresponding to two metamorphic episodes, one at c. 1000 Ma (M1) and the other at c. 500 Ma (M2). The latter is associated with a Pan-African tectono-metamorphic event that has been interpreted to represent a continent-continent collision followed by extensional collapse. Reaction-diffusion modeling of the compositional zoning of garnet associated with the development of reaction texture during M2 yields a time scale of ∼ 5-16 Myr for the duration of the peak of this overprinting metamorphism at ∼ 730 ± 20°C. The associated velocity of the reaction front is ∼ ∼ 5.0-1.6 μm/Myr. The inferred duration of peak metamorphism during the Pan-African event seems to be in good agreement with the available U-Pb SHRIMP ages of zircon and monazite that may be interpreted to have formed at the beginning and end stages of crystallization of granite during the metamorphic peak.

Original languageEnglish (US)
Pages (from-to)305-312
Number of pages8
JournalProceedings of the Indian Academy of Sciences, Earth and Planetary Sciences
Volume110
Issue number4
StatePublished - 2001

Fingerprint

granulite
zoning
garnet
metamorphism
texture
timescale
overprinting
monazite
modeling
zircon
crystallization
granite
collision
Antarctica
continent

Keywords

  • Diffusion
  • Reaction
  • Tectono-metamorphism
  • Time scale

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)

Cite this

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abstract = "Garnets from the S{\o}trene island, Antarctica, show reaction textures corresponding to two metamorphic episodes, one at c. 1000 Ma (M1) and the other at c. 500 Ma (M2). The latter is associated with a Pan-African tectono-metamorphic event that has been interpreted to represent a continent-continent collision followed by extensional collapse. Reaction-diffusion modeling of the compositional zoning of garnet associated with the development of reaction texture during M2 yields a time scale of ∼ 5-16 Myr for the duration of the peak of this overprinting metamorphism at ∼ 730 ± 20°C. The associated velocity of the reaction front is ∼ ∼ 5.0-1.6 μm/Myr. The inferred duration of peak metamorphism during the Pan-African event seems to be in good agreement with the available U-Pb SHRIMP ages of zircon and monazite that may be interpreted to have formed at the beginning and end stages of crystallization of granite during the metamorphic peak.",
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author = "Jibamitra Ganguly and Hensen, {B. J.} and W. Cheng",
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T2 - Modeling and constraint on the time scale of metamorphism during the Pan-African collisional event

AU - Ganguly, Jibamitra

AU - Hensen, B. J.

AU - Cheng, W.

PY - 2001

Y1 - 2001

N2 - Garnets from the Søtrene island, Antarctica, show reaction textures corresponding to two metamorphic episodes, one at c. 1000 Ma (M1) and the other at c. 500 Ma (M2). The latter is associated with a Pan-African tectono-metamorphic event that has been interpreted to represent a continent-continent collision followed by extensional collapse. Reaction-diffusion modeling of the compositional zoning of garnet associated with the development of reaction texture during M2 yields a time scale of ∼ 5-16 Myr for the duration of the peak of this overprinting metamorphism at ∼ 730 ± 20°C. The associated velocity of the reaction front is ∼ ∼ 5.0-1.6 μm/Myr. The inferred duration of peak metamorphism during the Pan-African event seems to be in good agreement with the available U-Pb SHRIMP ages of zircon and monazite that may be interpreted to have formed at the beginning and end stages of crystallization of granite during the metamorphic peak.

AB - Garnets from the Søtrene island, Antarctica, show reaction textures corresponding to two metamorphic episodes, one at c. 1000 Ma (M1) and the other at c. 500 Ma (M2). The latter is associated with a Pan-African tectono-metamorphic event that has been interpreted to represent a continent-continent collision followed by extensional collapse. Reaction-diffusion modeling of the compositional zoning of garnet associated with the development of reaction texture during M2 yields a time scale of ∼ 5-16 Myr for the duration of the peak of this overprinting metamorphism at ∼ 730 ± 20°C. The associated velocity of the reaction front is ∼ ∼ 5.0-1.6 μm/Myr. The inferred duration of peak metamorphism during the Pan-African event seems to be in good agreement with the available U-Pb SHRIMP ages of zircon and monazite that may be interpreted to have formed at the beginning and end stages of crystallization of granite during the metamorphic peak.

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