DECIPHERING ARCHEAN CONTINENTAL CRUST EVOLUTION FROM DETRITAL ARCHIVES: A MULTI-ACCESSORY MINERAL PERSPECTIVE ON THE PILBARA CRATON
Seminars
Semester 2
Reconstructing early Earth’s history is challenged by the limited and discontinuous preservation of ancient rocks, making detrital archives crucial. Zircon, rutile, monazite, garnet and titanite provide different responses to magmatic and metamorphic events and are highly to moderately durable minerals that can be preserved in ancient sediments, thus representing precious tracers in provenance analysis. Our study applies a comprehensive multi-mineral geochronological and geochemical framework to 8 river sand samples across the Pilbara Craton. Coupled U-Pb ages and trace element analyses of 1,156 detrital zircons brilliantly track the 3.45, 3.3, and 3.0 Ga magmatic events, revealing a deep, high-temperature regime with progressive crust recycling from 3.40 to 3.15 Ga, which transitioned into a mature, stabilized crustal state. Given the scarcity of coeval rocks, this provides compelling evidence of a profound geodynamic reorganization at ~3.15 Ga. To comprehensively detail the coupled tectono-metamorphic history, we further integrate monazite to date metamorphic peaks, garnet to evaluate high-pressure roots, and titanite/rutile to delineate exhumation and cooling rates. Ultimately, this integrated detrital mineral approach decrypts the Pilbara Craton's evolution from magmatic accretion to cratonization, establishing a robust framework to assess the growth and evolution of global Archean cratons and the onset of plate tectonics
For additional information, please contact Miss Yulin WANG, wangyl21@connect.hku.hk.