The Karoo Large Igneous Province: brevity, origin and relation with mass extinction in question from new 40Ar/39Ar age data.

Riley et al. (2006a) question our interpretations of 40Ar/39Ar data obtained on the Karoo fl ood basalts (Jourdan, et al., 2005). We believe their arguments are partially based on (1) poorly reliable 40Ar/39Ar age data (e.g., analyses of whole rocks that might have suffered hardly detectable alteration, recoil, etc.), and (2) mis-interpretation of the reliable geochronological data available on Karoo and other continential flood basalts (CFBs)