CHLORITE-CHLORITOID-GARNET EQUILIBRIA AND GEOTHERMOMETRY IN THE SANANDAJ-SIRJAN METAMORPHIC BELT, SOUTHERN IRAN

Document Type: Regular Paper

Author

Department of Geology, Tabriz University, 29 Bahman Blvd. Tabriz, I. R. of Iran, 51664

Abstract

Chloritoid is crystallised with chlorite, white mica and garnet in chlorite zone metapelites of
the regional metamorphic rocks of the Sanandaj-Sirjan metamorphic belt in southern Iran. Chemistry of
coexisting minerals is studied using microprobe analysis. Application of the chlorite-chloritoid
geothermometry gives temperatures of 515°C and 557°C. The Chlorite-garnet Fe-Mg exchange
geothermometer indicates temperatures between 442°C and 460°C for various pressures. A comparison
of the results from two geothermometers, along with a study of mineral assemblages in the rocks show
that the chlorite-chloritoid thermometer overestimates the temperature by about 70°C.

Keywords