Quantifying the Link Between the Detrital Zircon Record and Tectonic Settings

Full-plate reconstructions describe the history of past continental motions and how plate boundaries have evolved to accommodate these motions. Traditionally, tectonic reconstructions relied on geophysical data from the oceans and paleomagnetism as the primary quantitative constraints. However, these data do not directly constrain the paths of subduction zones or other plate boundaries, so reconstructing the complete configurations of tectonic plates in the past must rely on alternative methods. Here, we investigate the applicability of detrital zircon age spectra to characterize tectonic settings in deep time using a much larger data set than previously considered. We analyzed the proximity between reconstructed plate boundaries and sample sites assigned to different tectonic categorizations based on the proportion of zircon ages close to the depositional age and found that the categorization has an similar to 70% success rate in distinguishing convergent settings. Results are not strongly influenced by factors such as the number of zircon grains available within each detrital sample or uncertainty in the depositional age of the sample. The ability of the categorization to define extensional settings, such as rift basins, is less clear. Nonetheless, the broader pattern of results at the scale of Pangea shows that categorized zircon samples form a coherent pattern, where samples with dominantly young zircons lie at the supercontinent periphery while samples in the core of Pangea are dominated by grains much older than the age of deposition. This result suggests that zircon data could help to quantify uncertainties in full-plate reconstructions and discriminate between competing models for Proterozoic supercontinents.

Automated summary

Full-plate reconstructions are crucial for understanding the history of continental motions and plate boundary evolution. Traditional methods rely on geophysical data and paleomagnetism, but do not directly determine the paths of subduction zones and other plate boundaries. In this study, we analyze detrital zircon age spectra to characterize tectonic settings in deep time and find a success rate of approximately 70% in distinguishing convergent settings. The ability to define extensional settings is less clear. However, the overall pattern suggests that zircon data can help quantify uncertainties in full-plate reconstructions and distinguish between competing models for Proterozoic supercontinents.