Volcanic islands may be beautiful, but by geological standards, their “life cycle” is also short,media New Atlas reported. By analyzing 14 volcanic island chains, MIT scientists gained insight into why some islands exist longer than others and how this might affect their ecology.
If you look at the map of the Hawaiian Islands, you might notice that they are made up of a large island with several active volcanoes and a smaller and smaller smaller island that extends westward until they fade into several sandy atolls. Their formation is no accident, but an illustration of how volcanic islands were born and died. When hot lava spews out of the mantle and pierces the crust to form a new island, a chain of volcanic islands is formed, and then, under pressure from the magma plume, is pushed above sea level by a stretch of thousands of kilometers off the coast of the seabed.
However, magma plumes do not stay in one place, or, more accurately, the crust does not stay in one place. The tectonic plates of the planets have been moving in constant motion among themselves, resulting in more islands forming in the island chain for millions of years. As time went on, the oldest islands disappeared and sank into the sea. This process resulted in the Hawaiian Islands, canary islands and Galapagos chains. But the islands have a life span ranging from millions to 20 million years. The reason for this is unclear, but the MIT team says two of the decisive factors are the velocity of tectonic plates and the size of the seabed bulge caused by magma plumes.
Based on a study of 14 volcanic islands, the team found that the slower the plate moves, the larger the plume expands, the longer it lasts. That’s why the Hawaiian Islands live longer than the Galapagos Islands, the oldest in the world. By looking at how each island chain moves relative to the magma plume that formed them, the MIT team found that by dividing the expansion distance by the velocity of the plate, the length of an island can be determined directly above. The magma plume swells before sinking into the sea. This makes the island chain a kind of “treadmill”, life in a limited time to establish and develop.
“You’re looking at a process that helps the Galapagos Islands become a fast-moving ‘treadmill’, and the islands move very quickly and elongeise for a short time, which is what led to the discovery of evolution.” Leigh Royden, a professor of Earth, atmospheric and planetary science at the Massachusetts Institute of Technology, said. “So, in a sense, this process does provide a stage for humans to understand the meaning of evolution by exploring it in this microcosm. Without this process, the Galapagos Islands would not have had that short existence, and who knows how long it will take people to solve the problem. “
The study was published in the journal Science Advances.