Crustal metamorphic regimes in the ancient Earth
There has been much debate about the tectonic regimes and thermal evolution in the ancient Earth. Metamorphism provides a mineral record that may be inverted to yield ambient apparent thermal gradients for evaluating geodynamic regimes. This symposium will discuss the metamorphic patterns and evolution in the Archaean on the basis of field and petrographic observations, geochronology, geochemical records, and experimental and phase modelling. Some important questions to be addressed are: What types of metamorphism occurred during the evolution of Archaean greenstone belts and high-grade terranes? How did metamorphism evolve in Archaean times or from the Archaean into the Palaeoproterozoic? How can we recover metamorphic P-T-t paths for Archaean metamorphic terranes, especially for those with polyphase metamorphism? What are the relationships between the Archaean high- and ultra-high temperature granulite-facies terranes and the origin of tonalite, trondhjemite and granodiorite? How are the metamorphic records linked to the Archaean geodynamic regime?
Zhai Mingguo, Geoffrey Clarke, Chris Yakymchuck, Chunjing Wei and Shoujie Liu