T137 Work on the Zircon, Highlight the Apatite: Wielding the Power of Accessory Minerals and Honoring the Contributions of Bruce Watson, 2018 Roebling Medalist

Monday, 5 November 2018
1:30 PM - 5:30 PM
Room 240-241

DETRITAL ZIRCON TRACE ELEMENTS AS A PROXY FOR CRUSTAL EVOLUTION

Paper number: T137-5
Program: Technical Sessions
Time: 2:25 PM – 2:40 PM

Authors

Abstract

Detrital zircon U-Th-Pb, Hf, and O isotopic datasets have been utilized to track various aspects of tectonic processes and crustal evolution. While these studies have been informative, ambiguities remain between zircon records and the growth of continents. Zircon trace element (TE) compositions have shown the capability to track magmatic variability, though few studies have systematically focused on spatiotemporal variation in detrital zircon TE compositions. Thus, we generated a new global detrital zircon U-Pb and TE dataset via Laser Ablation Spilt Stream (LASS) ICPMS to further investigate evolution of the continental crust. Our new data were integrated with existing data and subjected to Monte Carlo analysis with weighted bootstrap resampling to minimize regional and temporal sample bias in order to provide global composite zircon TE records that spans over > 4 billion years of Earth history. These data reveal interesting temporal trends in crustal thickness and zircon crystallization temperatures. Notably, LREE/HREE and Eu/Eu* records indicate the development of thick and stable crust during the Archean, with a decrease in crustal thickness occurred through Proterozoic and Phanerozoic, which may correspond with changes in subduction processes. Crystallization temperatures calculated by Ti-in-zircon track temporal evolution of mantle temperature, which increase from ~3.5 Ga to a ~3.0 Ga peak and then decreasing progressively thereafter. These data are consistent with arguments for the Archean onset of lateral plate tectonics.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-320258

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