Why do you think the earth's crust is thicker under land than under bodies of water?
The Earth's crust is indeed thicker under land compared to bodies of water. This can be explained by the process of plate tectonics, which is the theory that the Earth's lithosphere (the rigid outer layer of the Earth) is divided into several large and small plates that are constantly moving and interacting with each other.
Underneath the oceanic crust, we have what is known as oceanic plates, which are relatively thin and dense. These plates are mainly composed of basaltic rocks. In contrast, the continental crust is part of the larger continental plates. These plates are thicker and less dense than the oceanic plates because they are made up of a variety of rock types, including granite and sedimentary rocks.
One of the reasons the continental crust is thicker is due to the process of subduction. When oceanic and continental plates collide, the denser oceanic plate tends to subduct, or sink, beneath the less dense continental plate. This subduction process causes the crust to buckle and fold, leading to the formation of mountain ranges. Over time, these collisions and subductions have contributed to the thickening of the continental crust.
Additionally, the presence of water can also influence the thickness of the crust. The weight of water in bodies of water exerts pressure on the crust below, which can cause the underlying lithosphere to sink slightly. This sinking, known as isostatic adjustment, can result in a thinner crust beneath bodies of water compared to under the land.
To learn more about this topic, you can explore resources such as geology textbooks, scientific journals, or educational websites that focus on plate tectonics and the formation of the Earth's crust.