Where to find sedimentary igneous and metamorphic rocks

In this investigation, students will explore how to use the physical characteristics of rocks to group and identify the rocks. This investigation is considered generally safe to do with students. Please also review the investigation for your specific setting, materials, students, and conventional safety precautions.

Remind students of the rocks that they studied in their first investigation. What was the same about the rocks? What was different? What characteristics did they think would be useful in identifying their rocks?

Make a list of their ideas to refer to during the investigation. Tell your students that they will be investigating this question and at the end of their investigations they will be able to provide reliable answers. Here are some initial questions that your students can discuss, in pairs, groups and as a whole class:. Have your students report out their ideas and make a list of them.

Give each group a new set of rocks you can switch rocks from group to group and ask the students to group the rocks based upon their characteristics. Ask them to give a reason for why they placed each rock in its group. Complete this investigation by asking your students to reflect on this question and how their answers may have changed as a result of this investigation.

Crystals in metamorphic rocks are often arranged in bands. Magma is composed of a mixture of molten or semi-molten rock, along with gases a nd other volatile elements. As you probably know, when magma cools, it turns into rock ; if it cools while still underground at high temperatures but at temperatures still lower than that of the magma , the cooling process will be slow, giving crystals time to develop. The crystals are also differentiated, as you can see below.

However, if the magma erupts or is cooled rapidly, you instead get a volcanic rock — — not really igneous, but also originating from lava.

The classical example here is basal t, which can have many small crystals or very few large ones. Volcanic rocks are also called extrusive igneous rocks, as opposed to intrusive igneous rocks. Not all magma is made equa lly: different magmas can have different chemical compositions, different quantities of gases and different temperature — and different types of magma make different types of rocks.

There are over hundred types of igneous rocks, and they are generally the hardest and heavies t o f all rocks. Pumice is created when a volcano violently erupts, creating pockets of air in the rock. The most common types of igneous rocks are:. Here, the name says it all.

Clastic material pieces of other rocks or fragments of skeletons may become cemented together and chemical precipitation and evaporation can form sedimentary rocks. Sedimentary rocks are usually associated with liquid water which facilitates erosion, transportation, deposition, and cementation. However, sedimentary rocks may also form in dry, desert environments or in association with glaciers.

Metamorphic rocks are igneous, sedimentary, or preexisting metamorphic rocks that have been changed by great pressures and temperatures within the crust and upper mantle of the Earth. The temperatures were not enough to melt the rock, otherwise, an igneous rock would have formed.

The pressures were much greater than those required to simply break the rocks into pieces. They were high enough to change the chemical make up of the rock by forcing the elements in it to "exchange partners.

Slate, which forms from the sedimentary rock shale, is very dense, smooth and does not contain visible minerals. Tyson Brown, National Geographic Society. National Geographic Society. For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher.

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You cannot download interactives. Metamorphic rocks start as one type of rock and—with pressure, heat, and time—gradually change into a new type of rock. Sedimentary rocks are one of three main types of rocks, along with igneous and metamorphic. Igneous rocks are one of three main types of rocks along with sedimentary and metamorphic , and they include both intrusive and extrusive rocks. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.

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