Brief History of the Earth

On an Expansion Tectonic Earth, for the first 3,750 million years of Earth's history all of the continents remained joined together as a complete supercontinental crustal shell on a smaller radius Earth. During that time the distribution of ancient seas coincided with a network of continental sedimentary basins. It was only during the past 250 million years that the ancient Pangaea supercontinental crust then ruptured and fragmented to form the modern continents, see:

In addition, during this same post-Permian time the intervening areas between each of the modern continents opened to form the modern oceans. This, in turn, was accompanied by intrusion of seafloor volcanic lava along the mid-ocean-ridges and expulsion of new seawater and atmospheric gases (pass your cursor over each of the Mesozoic and Cenozoic time periods at left).

It is also important to appreciate that on an Expansion Tectonic Earth, prior to crustal break-up, the ancient supercontinental crust had undergone an extremely long period of crustal stretching and complex distortion during on-going changes in surface area and surface curvature (pass your cursor over each of the Palaeozoic and Precambrian time periods at left). This change in surface curvature, in particular, gave rise to all of the geological features, such as folding and faulting, that are now preserved in the present-day crustal rocks. Change in surface curvature and re-equilibration of continental crusts is also the prime mechanism for more grandiose geological features, such as mountain building and tectonism.

In summary, the small Earth models shown here demonstrate that during the late-Permian Period—around 250 million years ago—rupture and eventual break-up of the ancient Pangaen supercontinental crust first began in earnest, resulting in formation of the modern continents and opening of the modern oceans. Prior to that time none of the modern continents existed in their present outlines. Instead, these modern continents were preceded by ancient supercontinents surrounded by a network of ancient continental seas.

Once rupture and breakup of the Pangaean supercontinent occurred each of the modern oceans progressively opened and increased their surface areas. This increase in surface area occurred throughout the modern oceans and the growth history is preserved as the coloured seafloor stripes shown on the Geological Map of the World map.