Mineral separates from three phonolite samples have been dated using 40Ar/39Ar techniques. Nepheline from the Duruchaus Spitskop of the Stalhart phonolite volcanic field near Rehoboth in central Namibia yielded a plateau age of 52.6±0.3 Ma from 55% of the degassed 39Ar. Sanidine from two samples collected on opposite sides of the Klinghardt volcanic field in SW Namibia yielded nearly identical plateau ages of 45.8±0.2 Ma and 46.6±0.2 Ma, each covering 98 % of 39Ar released. In contrast to previously published ages indicating that Klinghardt volcanism might have persisted for up to 8 Ma, our results strongly suggests that the Klinghardt volcanic field was emplaced in a narrow time interval (< several hundred kilo-years) at ≈46 Ma, consistent with its character as a monogenetic volcanic field and geochemical evidence for the phonolites collectively being part of a single strongly differentiated magmatic system. These new ages are important in establishing a secure time-frame for understanding the geomorphological evolution of the Namib Desert and its Palaeogene deposits. In this regard we offer a critique of the paper of Pickford et al. (2013) and show that their misinterpretation of the nature of the Klinghardt volcanism has resulted in a misleading model for geomorphological evolution in this region. Keywords: Klinghardt Volcanic Field, Stalhart Phonolite, Ar-Ar dating, southern Namib Desert.