Two 25 m sequences of slack water facies sediments have been dated in the Kuiseb River in Namibia by optical dating of sand-sized quartz grains. The eight samples indicate the sediments were deposited between 6.3 and 9.8 ka. This revises previous age estimates for the Homeb Silts. According to our criteria, six out of eight samples displayed characteristics of partial bleaching. This result was not unexpected as arid fluvial systems have high suspended sediment concentrations, short flow durations and a tendency for flow peaks to occur at night.