Linking detrital zircon record and supercontinent over the past 3.5 billion years

Abstract

Ideas on the history of supercontinents on Earth have moved beyond the most recent and well understood – Pangea – to establish the concept of supercontinent cycles over a much longer span of Earth history. A series of supercontinents including Rodinia and Nuna are proposed to have existed before the Phanerozoic, but many disagreements persist on their detailed history due to the limited, ambiguous geological record surviving from the Precambrian. One step towards resolving these issues is to integrate extensive databases of geological information within a global, quantitative reconstruction framework. Previous work demonstrated how samples with distinct zircon age spectra characteristics form coherent patterns in space across the past 400 Myr that delineate the periphery and core of Pangea. Here, we investigate the spatial and temporal characteristics of detrital zircon samples deposited over the past 3.5 Ga, and evaluate consistency between different reconstruction models and our expectations based on younger, more well-constrained periods. We find that the preference for detrital samples dominated by young zircons to be located closer to reconstructed subduction zones differs significantly between different reconstruction models, providing a basis for favoring some models over others. Although the number of available samples becomes sparser back in time, the patterns of the categorized samples in Proterozoic reconstructions are broadly consistent with previous results for Pangea, though reconstructed sample distributions indicate spatial bias towards sampling of Proterozoic supercontinent interiors not apparent for Pangea sampling. Global temporal trends reveal that, as supercontinents assemble, the proportion of samples characteristic of subduction tectonic settings increases while the proportion of samples from settings distal from subduction zones decreases, while the opposite trend defines periods of supercontinent dispersal. Together, these results show that quantitative reconstruction of global zircon databases holds important information related to past paleogeographic change.