Detrital zircon trace elements as a proxy for crustal evolution

  • Date

    December 18,2018

  • Time


  • Venue


  • Speaker

    Miss Liu Hangyu Department of Earth Sciences, HKU

Continental crust has helped modulate Earth system evolution through time. Despite extensive whole rock geochemical studies, some key questions regarding the evolution of the continental curst are still debated.  Due to zircon’s resistance to chemical and physical weathering, chemical analyses of detrital zircon offer a novel way to assess crustal composition through time. The trace elemental (TE) composition of zircon has shown the ability to track source magmatic characteristics, however, few studies have focused on detrital zircon TE data. Thus, I aim to explore the capability of zircon TE as a proxy for crustal and tectonic evolution. A new global detrital zircon U-Pb and TE dataset was generated via Laser Ablation Spilt Stream (LASS) ICPMS analysis. These data were subjected to Monte Carlo analysis with weighted bootstrap resampling to minimize sample bias. From the results, LREE/HREE, Eu/Eu* and crystallization temperatures of zircon indicate the development of thick and stable crust during the Archean, with a decrease in crustal thickness occurring through Proterozoic and Phanerozoic. Marked changes in trace element concentrations and ƐHf after 800 Ma imply less crustal reworking. These data may reflect secular changes in subduction processes through time. Future high resolution work will be conducted in regions with different tectonic backgrounds, such as Thailand, Japan and the Mariana islands, to test zircon TE’s utility in identifying various arc-type systems and detailed tectonic history