|Bridge over the Alfagja rift valley - the boundary
of the Eurasian and North American plates.
Rift valleys occur from the separation of continental plates.
The pulling apart of plates creates a linear-shaped lowland that, on land, is gradually deepened by erosion.
When continental spreading forces are strong enough, a center block will drop relative to the flanking blocks leaving steep flank walls.
The most extensive rift valley is the result of sea floor spreading. It is found in the subsurface of the Atlantic Ocean along the crest of the Mid-Atlantic Ridge.
This massive rift valley is expressed on land as it transects the interior of Iceland.
“People usually consider walking on water or in thin air a miracle. But I think the real miracle is not to walk either on water or in thin air, but to walk on earth. Every day we are engaged in a miracle which we don't even recognize: a blue sky, white clouds, green leaves, the black, curious eyes of a child -- our own two eyes. All is a miracle.”
― Thich Nhat Hanh
- Geology and tectonics of Þingvellir, Ólafur Ingólfsson, Professor of Glacial and Quaternary Geology, University of Iceland.
- Geology of Iceland, Wikipedia.
- Rift Valley, Wikipedia.