Evaluating the Age Distribution of Exposed Crust in the Acasta Gneiss Complex Using Detrital Zircons in Pleistocene Eskers

The Acasta Gneiss Complex (AGC) is a ∼2,400 km2 Hadean-Mesoarchean terrane that contains the oldest known zircon-bearing rocks on Earth. Despite its importance for early Earth geology, only small fraction (∼50 km2) of AGC has been mapped in detail. We use detrital zircon grains from late Pleistocene eskers transect to approximate lateral extent and relative proportions diverse-aged ancient rock units within vast, little-studied parts AGC. esker sediment was derived glacially eroded bedrock therefore can serve as proxy ages exposed study area. U-Pb dates ∼2400 zircons coarse fine grain-size fractions along yield age distributions coincide with regionally bedrock, adjacent Wopmay Orogen, granitoids Slave craton. Based new reconnaissance-scale mapping, we infer 3.37 Ga are volumetrically significant component unmapped Esker older than 3.7 present most samples but at low abundance, which suggests Eoarchean Hadean subordinate However, data also suggest least old 3.95 toward inferred eastern limit AGC, location where have not recognized previously.