T223 Radiogenic Isotopes as Tracers of Geologic Processes: Dates, Rates, and Proxies I

Wednesday, 12 October 2022
8:00 AM - 12:00 PM
502

SPATIAL DECLUSTERING OF ZIRCON DATA INDICATE RAPID ARCHEAN CRUSTAL GROWTH AND NEOPROTEROZOIC PLATE TECTONIC EQUILIBRIUM

Paper number: T223-3
Program: Technical Sessions
Time: 8:20 AM – 8:35 AM

Authors

  • Xi Wang Presenting Author
    University of Victoria, Victoria, BC
  • Xi Wang Presenting Author
    Queen’s University, Kingston, ON
  • Chris Spencer
    The Institute for Geoscience Research (TIGeR),, Perth

Abstract

Constraining the growth and evolution of the continental crust provides insight into the secular change of tectono-magmatic processes through time. Radiogenic isotope pairs such as 176Lu/176Hf are commonly used to track the growth rates of the continental crust. Previous studies utilizing global compilations of Lu-Hf isotopes of zircon to query continental growth through time. However, we show that sample clustering and spatial bias lead to erroneous interpretations and casts doubt as to the representativeness of global zircon compilations. To ameliorate this issue, we apply a geographic declustering algorithm to remove the spatial bias in the nonrepresentative dataset. A more representative declustered dataset indicates that the continental crust grew much faster than previous assessments have proposed. We further speculate that the transition to modern-style tectonics (as heralded by the appearance of low temperature–high pressure metamorphism) was accompanied by little to no net continental growth and propose that continental growth may be a feature of pre-plate tectonic magmatic processes.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-380591

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