[near center] is part of the Mid-Atlantic Ridge that
owes its very existence to the molten rock, or magma,
that wells up through the rifts along the ridge. Scientists
believe Iceland rose from the sea floor about 20 million
years ago. Continuous spreading, accompanied by eruptions
along Iceland's section of the ridge, widens the country
by about one inch per year.
Over one third of Iceland's 40,000 square
miles is volcanically active and loaded with lava
fields. Elsewhere, magma too far below the surface
to create volcanoes heats the rock above, sending
the heated groundwater percolating to the surface
in the form of "hot springs." Iceland is
far enough north so that it should be entirely covered
by ice and snow, like Greenland to the west. The heat
generated by the ridge, however, keeps the country
in a constant state of thaw, distinguishing it as
the Land of Fire and Ice.
Thanks to Bruce Heezen and Marie Tharpe.