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What rock makes up oceanic crust?
basalts
Oceanic crust, extending 5-10 kilometers (3-6 kilometers) beneath the ocean floor, is mostly composed of different types of basalts. Geologists often refer to the rocks of the oceanic crust as “sima.” Sima stands for silicate and magnesium, the most abundant minerals in oceanic crust. (Basalts are a sima rocks.)
What happens when the seafloor spreads?
Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor. Eventually, the crust cracks.
What will happen when oceanic and continental crust collide?
When an oceanic and a continental plate collide, eventually the oceanic plate is subducted under the continental plate due to the high density of the oceanic plate. Once again a benioff zone forms where there are shallow intermediate and deep focus earthquakes.
What happens to a rock as it goes deeper into the Earth?
The rock is pulled down by movements in the earth’s crust and gets hotter and hotter as it goes deeper. It takes temperatures between 600 and 1,300 degrees Celsius (1,100 and 2,400 degrees Fahrenheit) to melt a rock, turning it into a substance called magma (molten rock).
What is formed when magma cools at the earth’s surface?
When magma cools at the surface, it cools rapidly and does not have time to form very large crystals. Basalt, found on the ocean floor, is an example of an extrusive igneous rock. On the other hand, magma that cools slowly beneath the Earth’s surface forms rocks that contain large crystals.
How does the rock cycle affect the Earth’s crust?
The rock cycle is a series of processes that create and transform the types of rocks in Earth’s crust. This occurs as water travels through Earth’s crust, weathering the rock and dissolving some of its minerals, transporting it elsewhere. These dissolved minerals are precipitated when the water evaporates.
How does liquid magma turn into a rock?
You’d cool it by putting it into the refrigerator until it hardens. Similarly, liquid magma also turns into a solid — a rock — when it is cooled. Any rock that forms from the cooling of magma is an igneous rock. Magma that cools quickly forms one kind of igneous rock, and magma that cools slowly forms another kind.