Rapid cooling and exhumation in the western part of the Mesoproterozoic Albany-Fraser Orogen, Western Australia

摘要

The Albany-Fraser Orogen of southwestern Australia is an understudied orogenic belt, which is interpreted to record the Mesoproterozoic suturing of the Yilgarn Craton of Western Australia to the Mawson Craton of East Antarctica during Rodinia assembly. Previous U-Pb geochronology has dated peak amphibolite to granulite-facies metamorphism in the orogen at ca 1180 Ma. Here, we report the first Ar-40/Ar-39 thermochronology of hornblende, biotite and muscovite grains from a 360 km transect across the western Albany-Fraser Orogen, and uncover a record of strikingly fast syn-orogenic cooling and exhumation.