Reconstructing source-to-sink systems from detrital zircon core and rim ages

Grenville-age (1.3-0.9 Ga) zircons represent one of the most ubiquitous detrital zircon (DZ) age modes on Earth. In North America, given the widespread occurrence of Grenville basement, Grenville DZs are commonly viewed as nondiagnostic with regard to source region in provenance studies. Systematic recovery of DZ core-rim U-Pb ages makes it possible to identify and differentiate previously indistinguishable basement source terranes by leveraging their multistage tectono-magmatic evolution. Our analysis demonstrates that Grenville DZs exhibit distinct rim ages in different parts of the North American Paleozoic Appalachian-Ouachita-Marathon foreland. Whereas Grenville DZ grains in the eastern foreland, sourced from the southern Appalachian orogen in the eastern United States, exhibit Taconian and Acadian (490-350 Ma) rims, grains in the western foreland, derived from Mexico, mainly show Neoproterozoic (750-500 Ma) rim ages. This difference permits differentiation of non-diagnostic core ages by their distinctive rim ages. Furthermore, core-rim paired ages can illuminate potential genetic relationships among coexisting age components in DZ spectra, thereby indicating whether the DZs are derived from separate sources or from a single source with multistage tectono-magmatic histories. Thus, DZ rim-core ages can provide critical insights into reconstructing global source-to-sink systems and elucidating genetic linkages within multistage orogenic systems.

Automated summary

This study identifies previously indistinguishable source terranes by analyzing the differential rim ages of Grenville detrital zircons (DZs) in different regions of North America. The researchers found that Grenville DZ grains sourced from the southern Appalachian orogen exhibit different rim ages compared to grains derived from Mexico. This differentiation provides important insights into reconstructing global source-to-sink systems and understanding genetic linkages within multistage orogenic systems.