The submarine continental shelf is a natural extension of land to the ocean. Originally, the coastal plain was submerged by seawater and became a shallow sea on the continental shelf. The shallow sea on the continental shelf surrounds the landing land like a wreath, but its total area is 27.5 million square kilometers, which is equivalent to the area of the African continent. Most of the Bohai Sea, Yellow Sea and East China Sea in China are on the continental shelf. The seafood we eat, such as fish and shrimp, is mainly caught from the shallow sea of continental shelf, and the aquatic products in the shallow sea of continental shelf account for 80% of the whole marine aquatic products. The seabed of the continental shelf is rich in oil and natural gas, accounting for about 1/3 of the world. Many oil mines on land are also produced in the submarine environment of the continental shelf. The beautiful shallow sea scenery expanded to the 1950s, and geographers were able to map the underwater world with advanced technology. Surveying and mapping results show that there is a towering ocean "ridge" at the bottom of the ocean, forming an underwater "mountain range" that stretches for about 83,683.6 kilometers and runs through all the oceans in the world. The "sea ridge" at the bottom of the ocean is also called a rift, and magma keeps pouring out of the rift. After the magma cooled, a series of new submarine mountains were formed at the bottom of the ocean. This process is called submarine spreading, and these new submarine mountains are called seamounts. As new rocks are added to the fault valley, the rocks on both sides of the fault valley gradually move away from the center of the ocean ridge. So the farther away from the "mountain", the older the rock is. When seamounts and new submarine plains are formed, the magma in the fault valley will continue to gush out, playing the role of "conveyor belt", pushing the new seamounts out of the crustal rocks, and at the same time slowly pushing them down from the crustal rocks and remelting them into the mantle, thus achieving the balance of rebirth and growth.