Answer:
Plate Tectonics has four types of boundaries. Different rocks form at them. They are:
Plate Tectonics has four types of boundaries. Different rocks form at them. They are:Divergent boundaries - here two plates are pulling apart. They mostly occur in the deep ocean, but do occur on land. Iceland is a diverging boundary, as is the rift valley in Africa. In practically all cases, diverging boundaries result in a crack forming in the crust of the Earth at that spot. Logically, hot magma from under the crack will then seep out and erupt. Some of it will reach the surface. If it does, hills/mountains of a rock type called Basalt will form. Basalt forms from lava that is low in gas, and it oozes out rather than ejects out in big volcanic explosions. Because the magma/lava is free of gas, basalts tend to have few mineral crystals. They are dense, hard, blackish. Vast plains of basalt cover the bedrock of the ocean, because that is where the bulk of diverging plate boundaries occur.
Plate Tectonics has four types of boundaries. Different rocks form at them. They are:Divergent boundaries - here two plates are pulling apart. They mostly occur in the deep ocean, but do occur on land. Iceland is a diverging boundary, as is the rift valley in Africa. In practically all cases, diverging boundaries result in a crack forming in the crust of the Earth at that spot. Logically, hot magma from under the crack will then seep out and erupt. Some of it will reach the surface. If it does, hills/mountains of a rock type called Basalt will form. Basalt forms from lava that is low in gas, and it oozes out rather than ejects out in big volcanic explosions. Because the magma/lava is free of gas, basalts tend to have few mineral crystals. They are dense, hard, blackish. Vast plains of basalt cover the bedrock of the ocean, because that is where the bulk of diverging plate boundaries occur.Converging Ocean to Ocean, or Ocean to Continent boundaries - Here two plates come together, colliding. One of them usually slides under the other one, submerging deep into the mantle. As it does, it takes ocean water down with it, which turns to steam deep underground. That steam and CO2 from the ocean sediment then finds a way to come back up to the surface, and fill the magma with trapped gases. When it reaches the surface, volcanoes erupt with force, blowing their tops like Mt. St. Helens. Here is a graphic of both diverging and converging boundaries:
