Radiometric dating failed to yield a reliable age for the rocks; only an imprecise age of 690,000 ± 1,100,000 years ago was obtained. Later potassium-argon dating yielded an age of 200,000 ± 9,000 years before present for a lava bomb associated with the central cone, and the Global Volcanism Program assigns a Pleistocene age to Waw an Namus. Hot springs are active at Waw an Namus and produce sulfurous water.