Plate tectonics is the study of the lithosphere,
the outer portion of the earth consisting of the crust and part
of the upper mantle. The lithosphere is divided into about a
dozen large plates which move and interact with one another
to create earthquakes, mountain ranges, volcanic activity, ocean
trenches and many other features. Continents and ocean basis
are moved and changed in shape as a result of these plate movements.
Illustration
from USGS
The sequence of maps below show how a large supercontinent,
known as Pangaea was fragmented into several pieces, each being
part of a mobile plate of the lithosphere. These pieces were
to become Earth's current continents. The time sequence show
through the maps traces the paths of the continents to their
current positions..
In the early 1900's Alfred Wegener proposed the idea of Continental
Drift. His ideas centered around continents moving across
the face of the earth. The idea was not quite correct - compared
to the plate tectonics theory of today - but his thinking
was on the proper track. In addition, a variant spelling of
Pangaea is "Pangea". It appears in some textbooks
and glossaries, however, Pangaea is the current preferred
spelling.
Plate tectonics is the study of the lithosphere,
the outer portion of the earth consisting of the crust and part
of the upper mantle. The lithosphere is divided into about a
dozen large plates which move and interact with one another
to create earthquakes, mountain ranges, volcanic activity, ocean
trenches and many other features. Continents and ocean basis
are moved and changed in shape as a result of these plate movements.
