Ok (rhyming with 'talk') is a 1198 meters high dormant shield volcano with a central crater located to the west of Langjökull in the west of Iceland. In Icelandic Ok means load or yoke. The volcano erupted during interglacials in the Pleistocene (2,588,000 to 11,700 years ago). A late Pleistocene eruption produced a steep ice contact slope on the south-eastern side. The dolerite volcano was formerly covered by a small glacier on its top. In 1890, the Okjökull glacier was 16 square kilometres in size, and more than 50 m thick, but has since been mostly replaced (August 2011) by a small lake within the crater; with the glacier located on the northern slope, measuring less than 1 square kilometre, and less than 15 m thick. In order to fit the criteria glaciers need to be thick enough, about 40 or 50 meters thick, to sink and move under their own weight. Okjökull was the first Icelandic glacier to officially disappear. The Icelandic word for glacier is jökull
