The most common rocks on top of oceanic plates are basaltic rocks, which are denser than ones found on continents; these are found on top of the oceanic plates because they are pieces of the oceanic plates that have been pushed up through the crust. These kind of rocks are called sima, because the main minerals that compose them are magnesium and silicone.Continue Reading
Oceanic crust has to be less dense than continental crust, so it will sink. It is also the heavier of the two types. New rock is being constantly formed at certain points along the oceanic crust, by the Earth pushing outwards, forcing the old rock to the sides. Evidence of this has been found by testing the age of the rocks found at different sites. The person who discovered the new oceanic rocks that were consistently being formed was Alfred Wegener, the man who theorized Pangaea.
The ocean floor pushes out new rocks, made of sima, because it sits on something called the asthenosphere, a layer of molten rock that is so heated it acts like a fluid. As the oceanic plates move, the continental plates move. The oceanic plates push out new rocks through open crevices and thousands of miles away, in places like the Marianna Trench, the crust disappears down into the Earth, which leads scientist to believe that each plate behaves like a massive treadmill.Learn more about Layers of the Earth
Earth's crust is made up of 8 major plates and 9 minor plates. These plates are in constant motion because they are situated above hot flowing mantle rock often referred to as the asthenosphere.Full Answer >
The Earth is comprised of many diverse elements, including metals and minerals, sedimentary and molten rocks and water. The Earth is made of two distinct regions, which are the core and the surrounding atmosphere. The atmosphere contains mostly gaseous substances and liquids, while the crust contains solid elements such as rocks, dirt, soil and magmas.Full Answer >
The Earth has two crusts called the continental and oceanic. On average, the continental crust is 25 miles thick and the oceanic crust is about four miles thick.Full Answer >
Geologists study the structure and composition of the crust of the earth and examine rocks and minerals, applying their knowledge of physics, chemistry and biology when analyzing the results. A bachelor's degree is typically required to land an entry-level position, although a Ph.D. is necessary for more advanced positions, such as research or teaching college courses.Full Answer >