Single-pulse laser ablation–inductively coupled plasma–mass spectrometry U–Pb dating of thin zircon rims: An application to metamorphic rocks from Mount Everest, eastern Nepal

Abstract

This study describes an improved method for U–Pb dating of external zircon surfaces using laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS). Single-pulse LA of zircons mounted in Teflon by Excimer and femtosecond lasers produced age–depth profiles with 0.1 μm resolution. Application of this technique to samples from the Higher Himalayan Crystallines, Mount Everest region, eastern Nepal, revealed outer rims with ages of 15 ± 1 Ma. Most of these rims were not visible on cathodoluminescence images of polished cross-sections of the grains.