In August, we traveled to Iceland via a one-way flight from Denver. This, and a few future posts, will cover various aspects of this wonderful trip.
Iceland formed as an elevation of the ocean floor 20-24 million years ago and rises to 7,000 feet above sea level. The island was lifted by two forces: the separation of North American and Eurasian tectonic plates at the Mid-Atlantic Ridge, and a “hot spot” in the Earth’s mantel lying underneath Iceland.
According to Living Earth - Outline of the Geology of Iceland, the Mid-Atlantic Ridge “runs the length of the sea floor from the Arctic Ocean southwards past Africa.” Formed from the North American Plate and Eurasian plates, Iceland is slowly spreading, or “rifting”, along the Ridge.
The drifting or rifting rate is approximately 2 cm per year on average, but in reality the spreading is localized and a long time usually elapses between periods of drifting in a particular plate.
During rifting, magna normally rises to shallow depths within the crust to form intrusions, or less frequently reaches the surface in a single eruption or several eruptions during the rifting episode.
The mantel “hot spot” was crucial in Iceland's formation:
Only in certain locations are there hot spots underneath the oceans where magma production is sufficient to allow islands to form, among the most significant being Iceland, the Galapagos islands and the Hawaiian islands.
Þingvellir
As important as the rifting zone is to world geology, it is also important in Iceland’s history. Following the age of Settlement, the Commonwealth began in 930 AD with the establishment of an assembly, the Alþingi, said to be the world’s longest continuously active parliament. Each summer, the country’s chieftains met at Þingvellir, located in the rift valley, to adjudicate and create new laws.
According to Karlsson’s A Brief History of Iceland, each chieftain (historically numbering from 36-48) “could require every ninth farmer subject to their authority to attend the session with them.” With about 4,500 farmers on the Iceland during the Commonwealth, at least 500 men would be present, often accompanied by their immediate families.
The chieftains would selected two advisers and together would sit in a circle of benches. At the center, “the Lawspeaker" would "presided over the proceedings.” Appointed for a 3-year term, the Lawspeaker “was to memorize and recite the laws of the land.”
At Þingvellir, Iceland’s influence on Tolkien's during the writing of The Hobbit and The Lord of the Rings was coming into view. A sense of Middle Earth pervades this dramatic supramarine island.
References
Living Earth - Outline of the Geology of Iceland
Ari Trausti Guomundsson, Halldor Kjartansson, George Douglas
Publisher: Reykjavík : Mál og menning, 2007.
A Brief History of Iceland
Gunnar Karlsson (Author), Anna Yates (Translator)
Sunday, September 1, 2013 at 04:28PM 
