Microtextural analyses of detrital zircon for paleoenvironmental interpretations of metasedimentary rocks

Abstract

Sedimentary rocks archive the history of Earth’s surface. However, alteration by diagenesis, weathering, deformation, and metamorphism makes interpretating Earth’s earliest environments challenging and ambiguous. We show that detrital zircon grains preserve an unaltered account of transport history, even in billion-year-old sedimentary rocks. We systematically document microscopic features on modern zircon sand grains (“microtextures”) from three continental environments—aeolian, fluvial, and beach foreshore—in modern sediment and Phanerozoic sedimentary rocks of independently known transport history. Our statistical analysis reveals that microtextural assemblages can be used to diagnose transport settings in detrital zircon grains, including recycled grains. Finally, we demonstrate the applicability of zircon microtextural analyses to Precambrian metasedimentary rocks of independently but poorly constrained transport histories. Detrital zircon grains preserve an untapped account of early surface environments, expanding the applicability of sand microtextural analyses to the first 90% of Earth’s history.