Here we are approaching the Krýsuvík area where you will among other things see the beautifully colored móberg ridges formed by a series of effusive and explosive subglacial eruptions, which can be seen from the pillow lavas and tuffs appearing in the outcrops along the road.Seltún is the main geothermal area in Krýsuvík, where attempts to mine sulphur have failed in the late 19th century. The main sulphur area is a fumarole field in the mountain pass to the southwest.Mud pools and steaming ground, where white and yellowish brown sulphur and sulphates are deposited are common in the Seltún area.
Several maars, which are craters created by the explosions of overheated groundwater, are near the geothermal fields.Lake Grænavatn is one of the maar type explosion crater of a small volcano complex featuring eight craters in total. About 300m in diameter and 44m deep, lake Grænavatn is well known for olivine-gabbro zenoliths. The inner wall of the maar, shows that there was a powerful explosion when the eruption began, ejecting tephra and fragments of the country rock. The occurrence of the gabbro xenoliths in the tephra deposits suggests explosions as deep as 3km.We will depart at 15:30