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| 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.
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| Mid-Atlantic Ridge |
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
REFERENCES
- Geology and tectonics of Þingvellir, Ólafur Ingólfsson, Professor of Glacial and Quaternary Geology, University of Iceland.
- Geology of Iceland, Wikipedia.
- Rift Valley, Wikipedia.
