Abstract

Infrared laserprobe 40Ar/39Ar dating has been used to date pseudotachylite and host-rock minerals from a crush belt in the Lewisian basement of Scotland. It has revealed complexity in the pseudotachylite data that is attributable to the presence of refractory host-rock clasts and mineral fragments in the pseudotachylite. In conjunction with the host-rock mineral laserprobe 40Ar/39Ar data it has been possible to simplify the pseudotachylite data for the samples, and the preferred ages for these are: 980 ± 39 Ma, 999 ± 31 Ma and 1024 ± 30 Ma (2σ). These ages are the first record of Grenville-aged brittle deformation in the Lewisian. Further, this study serves to illustrate the complexity of dating pseudotachylites, and the advantages and limitations of the IR laserprobe applied to such materials.

You do not currently have access to this article.