Partial melting and P-T evolution of the Kodaikanal Metapelite Belt, southern India

K. Sajeev, M. Santosh, H. S. Kim

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)

Abstract

The Kodaikanal region of the Madurai Block in southern India exposes a segment of high-grade metamorphic rocks dominated by an aluminous garnet-cordierite-spinel-sillimanite-quartz migmatite suite, designated herein as the Kodaikanal Metapelite Belt (KMB). These rocks were subjected to extreme crustal metamorphism during the Late Neoproterozoic despite the lack of diagnostic ultrahigh-temperature assemblages. The rocks preserve microstructural evidence demonstrating initial-heating, dehydration melting to generate the peak metamorphic assemblage and later retrogression of the residual assemblages with remaining melt. The peak metamorphic assemblage is interpreted to be garnet + sillimanite + K-feldspar + spinel + Fe-Ti oxide + quartz + melt, which indicates pressure-temperature (P-T) conditions around 950-1000 °C and 7-8 kbar based on calculated phase diagrams. A clockwise P-T path is proposed by integrating microstructural information with pseudosections. We show that evidence for extreme crustal metamorphism at ultrahigh-temperature conditions can be extracted even in the cases where the rocks lack diagnostic ultrahigh-temperature mineral assemblages. Our approach confirms the widespread regional occurrence of UHT metamorphism in the Madurai Block during Gondwana assembly and point out the need for similar studies on adjacent continental fragments.

Original languageEnglish
Pages (from-to)465-483
Number of pages19
JournalLithos
Volume92
Issue number3-4
DOIs
Publication statusPublished - 2006 Dec
Externally publishedYes

Keywords

  • Kodaikanal Metapelite Belt
  • Pseudosections
  • Southern India
  • THERMOCALC
  • UHT metamorphism

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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