The record of geological processes in zircon from polymetamorphosed orthogneisses from the Napier Mountains, Napier Complex, East Antarctica

The Napier Complex in Enderby Land and western Kemp is a unique component of the East Antarctic Shield because it records timeline crustal growth from Eo- to Neoarchean. It mainly composed enderbitic charnockitic gneisses granulites that were metamorphosed at ca. 2.5 Ga, locally 2.8 under high- ultra-high-temperature conditions. Despite generating scientific interest for several decades, geological history complex has not been well constrained. In this study, samples Mountains selected zircon imaging U-Pb dating by Secondary Ion Mass Spectrometry. They record metamorphic growth, recrystallization, modification 2800-2770, 2740-2720 Ma 2490-2460 Ma. For first time, fluid-related alteration around 2730 evident granitic gneiss Grimsley Peaks. At similar dioritic was formed Mount Marr. Tonalitic Peaks yield protolith crystallization ages 3210 2825 Ma, respectively. generation coeval with ∼2.8 Ga metamorphism area. These new data little-known part provide better understanding evolution Complex.