Asbyrgi Canyon, NE Iceland

Asbyrgi was one of the most magical places we visited in Iceland yet barely anyone goes there! A horseshoe-shaped canyon roughly 3.5km long and 1km wide, according to the Vikings Asbyrgi formed where Odin’s eight-legged horse Sleipner planted its foot. Alternatively the canyon formed 8-10 million years ago due to catastrophic flooding of the Jokulsa a Fjollum river following an eruption beneath the Vatnajokull ice, not far to the south. Similar flooding reoccurred some 3000 years ago and a vertical cliff at the southern end of Asbyrgi (from where the photo below is taken) marks the site of a formerly enormous waterfall carrying the flood waters to the sea.

What caught my eye is the sharply defined edges of the canyon picked out in the perspective view from Google Earth (below, looking south) and shown also from ground level in my photo (taken at the end of the canyon, looking north). They are normal fault scarps, the surface traces of active faults . This means Asbyrgi is not just a river canyon but also a rift valley that formed where a ‘keystone’ block of crust dropped down along fault lines due to crustal stretching. Whether the stretching was a response to doming above shallow volcanic material , or if it’s tectonic extension related to the plate margin that runs through this region is not clear. There are several other examples of fault scarps in the area which we saw from the road on our drive out.