what is the difference between extrusive and intrusive igneous rocks This is a topic that many people are looking for. savegooglewave.com is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, savegooglewave.com would like to introduce to you Igneous Rocks Introduction. Following along are instructions in the video below:
Rocks are one of the three major rock types the other types are sedimentary and and metamorphic rocks igneous rocks form from cooling magma or lava this brings about a distinction the difference between magma and lava magma is below the surface of the earth and lava is above the surface of the earth. So for example magma turns into lava when a volcano erupts as magma or lava cools that they form crystal structures that are characteristic of igneous rocks the varying sizes and composition of these crystals tells a lot about the rock and its formation there are two major classifications of igneous rocks these are intrusive igneous rocks and extrusive igneous rocks and these two classifications go along with the two definitions of magma and lava. Intrusive rocks cool slowly below ground or magma while extrusive rocks will quickly above ground from lava.
This is one of the reasons. Why theres a key distinction between magma and lava because of the different types of digne stocks that they each form the slow cooling of intrusive rocks leads to larger crystal sizes these have larger crystals because the slower cooling time allows for the crystals to grow over a longer period of time the slower the magma cools the larger the crystals are in the resultant igneous rock. The opposite is also true the faster lava cools the smaller the crystals are in that igneous rock.
Again this is because a faster cooling time leads. The less time for those crystals to grow before they solidify this cooling and crystal formation also plays a key role in radiometric or absolute rock date. Once the crystal solidifies this begins.
The countdown timer for radiometric data. And when we date a rock using absolute or radiometric dating. Were determining how old it is based on the point when it first crystallized lets take a look at a couple unique igneous rocks.
These are pumice and obsidian pumice is actually an igneous rock that forms from foamy lava. So that it has very small air pockets in it such that it has a density less than water this means it will actually often float in water another interesting igneous rock is obsidian obsidian is known as a glassy black rock. And it forms this way because of super fast.
Cooling obsidian cool. So quickly that individual crystals cannot form inside. It is essentially one giant crystal or one giant piece of glass.
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