Earth scientists have confirmed that since the formation of the earth, the land and sea pattern has gone through many times, sometimes it is a whole continent, sometimes it is fragmented, and finally forming the land and sea pattern of today's world. When we play a jigsaw puzzle, the pieces of the jigsaw puzzle move apart and together to finally form a complete picture because we use our fingers to stir the pieces. So what forces do the land and sea pattern on the earth's surface, which is similar to a "super big jigsaw puzzle", make these continents merge and merge for a long time? There is obviously no "hand of God" from the outside. Earth scientists look to the interior of the earth.
In daily life, if you have ever had the experience of boiling water, you will know that the water at the bottom rises when heated, while the cold water at the top sinks, forming a recyclable convection. Earth scientists have discovered that there are many similar thermal convective cycles in the mantle. Due to the very high temperature inside the earth, the mantle material takes on a very soft state and can flow driven by heat energy. Specifically, after the material in the deep mantle absorbs heat, its density decreases, and its volume expands to produce rising heat flow. The rising mantle material reaches the bottom of the crust and diverts to all directions. As the temperature drops, the density of the mantle material increases and sinks into the mantle. This is the mantle convection process. Mantle convection was first proposed by British geologist Holmes in the 1930s. At that time, he imagined the earth's crust floating on the flowing mantle like a raft to explain the continental drift hypothesis put forward by Wigner.
So, does the earth's crust move on the mantle? Earth scientists used the "bright light" of seismic waves to further detect the properties of underground materials and found that the uppermost part of the mantle was also solid, and this part was connected to the earth's crust. Obviously, the earth's crust did not move on the mantle. The only possibility is that the crust and the upper mantle are moving slowly together, pulled by convection in the lower mantle. Earth scientists call these two closely connected "solid brothers" the lithosphere. There are many cracks in the lithosphere that divide the lithosphere into multiple blocks called plates. The movement of the lithosphere plate is reflected in the movement of the surface and the earth's crust, which is the source of power for the evolution of the surface land-sea pattern.