Spatial declustering of zircon data indicate rapid Archean crustal growth and Neoproterozoic plate tectonic equilibrium

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.

Automated summary

Constraining the growth and evolution of the continental crust provides insight into the secular change of tectono-magmatic processes through time. However, previous global compilations of Lu-Hf isotopes of zircon suffer from sample clustering and spatial bias issues. By applying a geographic declustering algorithm, a more representative dataset reveals that the continental crust grew much faster and suggests that continental growth is a feature of pre-plate tectonic magmatic processes.