The Rock Cycle

The Rock Cycle …is the natural process that rocks in the Earth's crust go through, that involves them continuously transforming into igneous, sedimentary, and metamorphic rocks.

What is a Rock? Naturally Occurring (not man made) Solid Mixture of minerals and organic matter

What makes a rock different from a mineral? Both Mineral Made of one or more minerals Solid Made of 1 type of element Random crystal or no crystal structure Naturally Occurring Orderly crystal structure Quartz Granite = Feldspar Muscovite

Types of Rocks Sedimentary: Sandstone Metamorphic: Gneiss Igneous: Diorite

Igneous Rocks

Igneous Rocks are formed from Magma and Lava Igneous rocks are classified by where they form Intrusive Extrusive vs. forms when magma cools in the Earth forms when lava cools on Earth’s surface

Intrusive Vs. Extrusive Diorite Granite Basalt Andesite Ask the students to take a few minutes to compare intrusive to extrusive. You could have them brainstorm on whiteboards as a group or a piece of paper and then share their observations. Pegmatite Gabbro Rhyolite Scoria 8

Extrusive (earth surface) Igneous Rocks: Crystal Size and Cooling Time Location of Rock Intrusive (in earth) Extrusive (earth surface) Crystal Size Large crystals Small crystals Picture Cooling time Longer cooling time Shorter cooling time 9

Sedimentary Rocks

Sedimentary Rocks form from sediment or rock particles Sediment = material that is deposited by air, water, or ice. These materials can be: tiny pieces of rock broken minerals pieces of plants and animal remains

How do sedimentary rocks form? Sediments pile on top of each other on land or in water. As sediments pile, they become compacted and cemented together. This forms cemented layers of sediment.

Sedimentation Process

Sedimentary Rock Layers

Sedimentary Rock Layers

Some rocks form from plants or shells Coal- created from the remains of plants (dead wood, bark, leaves, stems, and roots) The coal we use today started forming millions of years ago in swamps Limestone- created from the shells and skeletons of ocean organisms.

Limestone Formation

Metamorphic Rocks

Metamorphic Rocks Extreme heat and pressure can change rocks. The original rock is called the parent rock The new rock formed is called the metamorphic rock Heat and pressure change the structure of the parent rock and their minerals recrystallize

Examples of Metamorphic Rocks Extreme heat and pressure Parent Rock Shale Metamorphic Rock Slate

Examples of Metamorphic Rocks Extreme heat and pressure Parent Rock Limestone Metamorphic Rock Marble

Examples of Metamorphic Rocks Extreme heat and pressure Parent Rock Mica Metamorphic Rock Phyllite

A little bit more about igneous rocks… Granite Rhyolite

IGNEOUS ROCKS GABBRO BASALT

Composition of Igneous Rocks Igneous rocks are mainly composed of silicate minerals (quartz, feldspar,etc.) Rocks with high silicate levels-are typically light in color ex: granite, rhyolite Rocks with low silicate levels- dark in color ex: gabbro and basalt

Igneous rocks make long-lasting landforms Intrusive rock formations-as magma pushes up toward Earth’s surface, it makes channels and other formations underground. Extrusive rock formations- builds plateaus when erupting from long crack gently sloping volcanoes (Hawaiian islands) cone-shaped volcanoes (1). contains greater amount of silica (2). erupts explosively (3). Mount St. Helens is an example

RECAP: Rock cycle-the set of natural processes that form, change, break down, and re-form rocks

Rocks are always changing by processes like: When a rock forms, does it stay that way forever? NO!!!!!! Rocks are always changing by processes like: Weathering Melting Erosion Cooling Compaction Cementation

Our world is built of rocks Rocks have many purposes used to build houses and skyscrapers great source of metals used to carve statues and other works of art

11. Rock Cycle Rocks can change from one category or rock into another The rocks can move through the cycle in many ways, there is no particular order they must follow 31

Rock Cycle animation Click the link in the title to go to an animation of the rock cycle.