|Four Points of Plate Tectonics
Fig. 1 Angles through Earth, pointing out the four
main points of plate tectonics, Iceland (top), Hawaii
(left), South Sandwich Islands (bottom), Afar (right).
The four points of interest concerning Plate Tectonics
point out the angles through the Earth. (See figure 1). The
four points of interest are: Iceland, which sits atop the Mid
Atlantic Ridge, Hawaii; known as a "thermal anomaly" (3),
South Sandwich Islands, locating the “gap” in the South
Atlantic, near Falkland Islands, and Afar, in northeast
Africa, also known as a triple junction.
Some Pacific islands, like
Hawaii, are located over a
thermal anomaly, or hot spot,
and are used as a linear
tracking of the movement of
the Pacific plate, specifically
in a northwesterly direction.
The Pacific plate is currently
moving toward the northwest;
it switched to that course
from a more northerly
heading about 40 million
The Emperor Seamounts probably once stood above the water, much like present day Hawaii (1). There are
two other hot spots with underwater seamounts like the Hawaiian Island-Emperor Seamount chain. They are
called the Tuamotu Archipelago Line Island chain and the Austral, Gilbert and Marshall Islands chain. All
three chains are approximately parallel and could all have been formed by the same motion of the Pacific
plate over three fixed hot spots. These three hot spots are significant evidence of dramatic events, of which
the Hawaiian hot spot is probably the most "recent." All taken together then, it appeared to me that this
explosion of the heat chamber in the ancient past occurred more than once (See Figure 2).
The hot spots [specifically the Hawaiian hot spot] provide a worldwide reference frame for tracking the
absolute motions of the plates with respect to Earth's interior. The boundary between plates, which include
the ridges and trenches, also move. However, the relative motions do not reveal where on the globe a plate
was at a given time (4). The volcanoes that formed these islands are produced assembly line style, as the
pacific plate passes over a hot spot in the mantle. As the ocean floor moves over the hot spot, at about five
inches a year, the up-welling lava material creates a steady succession of new volcanoes that in turn migrate
with the plate. Supporting this theory, the northwestern most seamounts or oceanic plateaus, called the
Emperor Seamounts, are the farthest from the hot spot, and they show the greatest age.
The trail of underwater mountains created as the the tectonic plate moved across the Hawaii hotspot
over millions of years, known as the Hawaiian-Emperor seamount chain, or the Emperor Seamounts.