Abstract
The evolution of continental crust during Hadean and Archean and related
geodynamic processes provide important clues to understand the early Earth
history. Here we report evidence for Hadean and Eoarchean crust from the
fringe of the Coorg Block, one of the oldest crustal blocks in Peninsular India. We
present geological, petrological, and geochemical data, together with zircon U-Pb
ages and Lu-Hf isotopes from a suite of metaigneous (granitoids, diorite,
charnockite, metavolcanics) and metasedimentary (quartz mica schist,
calcareous schist, ferruginous quartzite and BIF) rocks. Petrological and
geochemical studies indicate that the igneous suite formed from subductionrelated
arc magmatism, and that the sedimentary suite represents an imbricated
accretionary package of continental shelf sequence and pelagic components.
Mineral thermometry suggests metamorphism under temperatures of 710-730°C
and pressures up to 8kbar.