A new ocean basin is created when a tectonic plate carrying a continent literally splits apart. In this process the heat from underlying magma wells up from deep within the earth, weakening and stretching the overlying continental crust. The brittle crust then fractures on each side of the stressed area, allowing sections to drop. The result is a rugged terrestrial rift valley.

This early stage of ocean building is evident in several parts of today’s world, including the Baikal region of southeastern Siberia known as the Basin, and the United States from western Utah to eastern California, an area known to geologists as the Range. But the most dramatic example of an emerging ocean basin in its infancy is the Great Rift Valley of East Africa, stretching between Ethiopia and Tanzania.

As the continent of Africa breaks apart along this 1,500 mile rift, a new plate (the Somali Plate) is taking shape. In time, the sea will invade the gap created by the separation, thus forming a new ocean basin. The Red Sea is a widening ocean basin located where the Arabian Peninsula was severed from Africa long ago by the pulling apart of the African Plate and Arabian Plate. Africa is literally coming apart at the seams.

As a young ocean widens and matures, the undersea rift develops a ridge of lava mountains on the trailing edge of each plate. The Mid-Atlantic Ridge, for example, rises where the American continents are separating from Europe and Africa. Other Mid-Ocean Ridges include the East Pacific Rise, several hundred miles off the western coast of South America, and the Indian Ridge, off the Eastern coast of Africa, south of India. Each of these mid-ocean ridges first appeared as a terrestrial rift valley involved in the break-up of some ancient land mass.
   
< Previous Page Next Page >