History of Rocks

Associate Level Material

History of Rock Worksheet

Write a 500- to 750-word explanation regarding the role of plate tectonics in the origin of igneous rocks.

|The role of plate tectonics in the origin of igneous rocks is very important.   Igneous rocks are formed within three main areas; at|
|lithospheric plates that are pulled at the ridges of the mid-ocean areas, seduction zones are where the plates join together, and   |
|where the continental crust has been pushed together.   There are two ideas that are voiced when it comes to igneous rocks.   The     |
|first idea is that igneous rocks do evolve meaning they can change from one type of rock into another.   The second idea is that     |
|rocks are not distributed randomly throughout the Earth.   Certain types of rocks are usually found in a specific area for a         |
|particular reason, yet all of these are combined into the process of plate tectonics. The word igneous stems from the Latin word   |
|“fire”.   Igneous rocks start out as a liquid hot material.   The material could have been from lava that had been erupted at the     |
|Earth’s surface, un-erupted lava or magma at shallow depths, or even plutons (magma that is in a deep body).   People usually think |
|of magma or lava as a liquid comparable to liquid metal.   However, geologists have found that magma is mostly a liquid that has a   |
|load of the mineral crystals in it and has the consistency of mush.   Magma then crystallizes into a corporation of minerals and     |
|some of these minerals crystallize faster than the others.   When these minerals crystallize they leave the remnants of the liquid   |
|that has a changed chemical composition.   As magma cools it eventually starts evolving as it goes through the crust and interacts   |
|with other rocks.   You can tell the types of these igneous rocks by the texture of the rocks from the mineral grain size.           |
|Extrusive rocks cool more quickly from seconds to months and have very small...