Hydration of orthopyroxene-cordierite-bearing assemblages at Laouni, Central Hoggar, Algeria

M. Guiraud*, R. Powell, J. Y. Cottin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


In the Laouni region (Central Hoggar, Algeria), retrogression of high-grade orthopyroxene cordierite-bearing rocks led to the crystallization of orthoamphibole and garnet, and at a later stage of chlorite, from the original paragenesis. Calculated phase diagrams show that this retrogression occurred at about 3 kbar with the simplest model involving hydration at 650-700°C and at around 500°C, with the rocks experiencing aH2O less than 1, except possibly in the last stages of chlorite crystallization. As the other rock types occurring in the same area as the orthopyroxene-cordierite rocks display similar features, it is concluded that regional hydration occurred, presumably related to the release of fluids during the crystallization of the Pan-African granitic and mafic magmas that are widespread in the Laouni area.

Original languageEnglish
Pages (from-to)467-476
Number of pages10
JournalJournal of Metamorphic Geology
Issue number4
Publication statusPublished - 1996
Externally publishedYes


  • Cordierite
  • Hoggar
  • Hydration
  • Orthoamphibole
  • Orthopyroxene


Dive into the research topics of 'Hydration of orthopyroxene-cordierite-bearing assemblages at Laouni, Central Hoggar, Algeria'. Together they form a unique fingerprint.

Cite this