Dating high temperature metamorphic rocks: a case study of isotopic and trace element complexity in zircon and monazite from South India

Abstract

Metasedimentary rocks from the Trivandrum Block and Achankovil Zone in South India have been used to study zircon and monazite behaviour during high-temperature metamorphism. Isotopic and chemical data from these accessory minerals reveal that metamorphism had begun before $\sim$600 Ma and was waning by $\sim$510 Ma, but widespread disruption of this isotopic record by differential lead-loss and contamination with reset inherited grains make it difficult to date specific stages within this prolonged orogenic history.