EARTH : marine world

 The Marine World :

The ocean unit :

    Photographs of the Earth from space clearly show the location of its continents and oceans. In addition, the same photos taken millions of years ago (MA), would show that the land masses have fragmented and joined together several times. About 250 million years ago, Earth had only one continent, called Pangea, surrounded by an ocean, known as Panthalassa. This unique ocean split at the same time as the land masses, but the oceans remain linked and function as a whole. What affects one of them inevitably ends up affecting the others.

The giant puzzle of the continents :

    Imagine that the continents are pieces of a giant jigsaw puzzle and you will see that they fit together quite well. The bulge of northwest Africa corresponds to the troughs between North America and South America, proving that these continents were once united. The discovery of identical fossils on different continents helps support this theory.

>> In the past, the movements of the continents and the formation of the oceans have modified the Earth's climate

. >> Scientists fear that the warming of the atmosphere will affect the oceans and their currents, which would have an influence on climate patterns. 

>> The Arab-Persian Gulf was formed only 3 or 4 million years ago, which is very little in "geological" time. As it moved, the land around it made the rock crinkle and sag, giving rise to a hollow basin (gulf).

Continental Drift :

    Nowadays, continents keep moving and transforming extremely slowly, in a process called {continental drift}. The lithosphere, the planet's rigid outer layer, cracks into a dozen tectonic plates of varying sizes. These plates slide on a more fluid layer, dragging the continents they carry.

Climate and currents :

    Ocean currents greatly influence the climate and meteorology on dry land. Take the example of London and Moscow which should theoretically have the same climate because they are located at roughly the same latitude (distance from the equator). But in fact, London benefits from much milder winters thanks to the Gulf Stream, a warm oceanic current that goes from the Caribbean to Great Britain; While Moscow, much further inland, freezes in winter with temperatures of -10 ° C.

Ever larger oceans :

    This sonar image shows the Eastern Pacific Ridge, which is part of the Mid Pacific Ridge. The raised area draws a line where the tectonic plates move away from each other, forming new soil that helps expand this area of ​​the Pacific. >> dark blue areas indicate deeper areas and red areas higher.

The Red Sea rift :

    The Red Sea formed around 50 million years ago, when Africa began to move away from Arabia, creating a deep rift. Currently, the Red Sea continues to widen by about 2cm per year. And it might be 150 million years from now as wide as the Atlantic Ocean.