Rocks WebQuest!

1. Rocks WebQuest! • For this WebQuest you will investigate the three types of rocks and a few examples of each • You will work in partners for this assignment sharing one laptop. • You will fill out the notes sheet using this power point for the information. • The information goes in order- you must search for the missing sections or questions asked. • You should work on this the entire class period. • There is an attached assignment for sorting the rock types and table generating for classifying.

2. Rocks… • Rocks are always on the move through the rock cycle! The three types of rocks are: • sedimentary rocks • igneous rocks • metamorphic rocks • This process is slow! • All rock (except for meteorites!) that is on Earth today is made of the same stuff as the rocks that dinosaurs and other ancient life forms walked, crawled or swam over. While the stuff that rocks are made from stays the same, the rocks do not. Over millions of years, rocks are recycled into other rocks. Moving tectonic plates help to destroy and form many types of rocks.

3. Sedimentary Rocks What Is a Sedimentary Rock? • Have you ever been to the beach and nestled your toes in the sand? Over thousands of years that sand might become part of a sedimentary rock! • Sedimentary rocks make up about three-quarters of the rocks at the Earth’s surface. They form at the surface in environments such as beaches, rivers, the ocean, and anywhere that sand, mud, and other types of sediment collect. Sedimentary rocks preserve a record of the environments that existed when they formed. By looking at sedimentary rocks of different ages, scientists can figure out how climate and environments have changed through Earth’s history.Fossils of ancient living things are preserved in sedimentary rocks too.

4. Cont… • Many sedimentary rocks are made from the broken bits of other rocks. These are called clastic sedimentary rocks. The broken bits of rocks are called sediment. Sediment is the sand you find at the beach, the mud in a lake bottom, the pebbles in a river, and even the dust on furniture. The sediment may, in time, form a rock if the little pieces become cemented together. • There are other types of sedimentary rocks whose particles do not come from broken rock fragments. Chemical sedimentary rocks are made of mineral crystals such as halite and gypsum formed by chemical processes. The sediment particles of organic sedimentary rocks are the remains of living things such as clamshells, plankton skeletons, dinosaur bones, and plants.

5. Sedimentary Examples • Limestone • Sandstone • Shale

6. Limestone • Limestone is formed in marine environments where bits of shell and other debris composed of calcite are deposited on the bottom. Chemical reactions between calcium and bicarbonate ions may also form carbonates, which settle to the bottom. The calcite and other minerals may harden into limestone. Remains of animals may also be buried in the carbonate muds and eventually turn into fossils. Over time uplift and lowering of sea level may expose the limestone layers at the Earth’s surface.

7. Sandstone • Sand is carried by wind or water until it is deposited in a basin. Some dissolved chemicals in rising groundwater are deposited in spaces between the sand grains. This chemical matrix glues individual grains together and forms the rock we call sandstone.

8. Shale • Clay and silt size particles are deposited in areas of slow moving water. Leaves and other remains of plants and animals may get buried in the mud. Over time, the pressure of overlying sediments may squeeze the water out of the mud, and forms shale.

9. Igneous Rocks… • Igneous Rocks • Igneous rocks form when molten rock cools and becomes solid. Molten rock is called magma when it is below the Earth’s surface and lava when it is above. • Igneous rocks are divided into two groups, based on where the rock forms. • Igneous rocks that form below the Earth’s surface are called intrusive igneous rocks (or plutonic). They form when magma enters an underground chamber, cools very slowly, and forms rocks full of large crystals. • Igneous rocks that form above the Earth’s surface are called extrusive igneous rocks. These rocks, also called volcanic rocks, form when lava cools quickly at or above the Earth’s surface.

10. Igneous Examples • Obsidian • Granite • Basalt

11. Obsidian • Obsidian is formed by rapid cooling of lava. It cools so quickly it forms glass and not crystals.

12. Granite • Granite is formed below the Earth’s crust from slowly-cooling magma. Slow cooling allows larger crystals to form.

13. Basalt • Basalt is formed from lava erupting onto the Earth’s surface. It cools relatively quickly; only small crystals form which are not easy to see.

14. Metamorphic Rocks… • Have you have heard that caterpillars metamorphose into butterflies? Well, rocks can metamorphose too! They don't grow wings like a butterfly. But they do change! Rocks metamorphose when they are in a place that is very hot and pressure is high. You can find such a place where Earth's tectonic plates are coming together. There, the colliding plates squish rocks, and hot pools of magma heat them deep underground. • Some rocks only change a little, while others change a lot. When a rock is metamorphosed, its mineral crystals change. Usually, the same chemical ingredients are used to form new crystals during metamorphism. Sometimes new types of minerals grow that weren't in the rock before.

15. Cont… • Often, flat minerals like mica become lined up perpendicular (at a right angle) to the direction of pressure. When minerals within a metamorphic rock are organized this way, it is called foliation. Some metamorphic rocks are foliated and others are non-foliated. • Any type of rock, can be metamorphosed. The rocks are changed either in small areas of contact metamorphism or large areas of regional metamorphism.

16. Figure out foliation! • Try this experiment to figure out how minerals become oriented when a rock is under pressure. • Add mica flakes to a piece of play dough. The dough will represent a rock undergoing metamorphism. • Knead the dough until the mica flakes are well-incorporated roll your dough into a ball. • Break the ball of dough in half. The flakes will be oriented in all different directions just as they would be in an unmetamorphised rock. • Take one half of the ball and flatten it with the palm of your hand. The pressure that you are applying to the dough is like the pressure placed on our rocky Earth by the forces of plate tectonics. • Break the flattened dough in half and look at what has happened to the mica flakes!

17. Metamorphic Examples • Gneiss • Schist • Slate • Quartzite • Marble

18. Gneiss • Gneiss may be formed from any rock type that is buried deep in the Earth’s crust and affected by the great pressure and temperature that exists there.

19. Schist • Schist is formed when rocks, such as granites, are changed by moderate heat and temperature after burial deep in the Earth’s crust.

20. Slate • Slate is formed when fine-grained sediments, such as shale and mudstone, are buried in the Earth’s crust. Here the sediments are recrystallized by low temperatures and pressures.

21. Quartzite • Quartzite (also known as metaquartzite) forms from sandstone that comes in contact with a source of heat, such as an intrusion of Igneous rock.

22. Marble • Marble forms from calcite-rich rocks, such as limestone, that come in contact with a source of heat, such as an intrusion of Igneous rock.

23. Rock Organization Slate Limestone Shale Granite Schist Gneiss Obsidian Marble Sandstone Basalt Quartzite MetamorphicIgneousSedimentary *Organize the rocks under the correct grouping *Come up with a few facts that are true with all the rocks in each rock type. ~Use your notes to help you!

24. Rock Classification • How would you classify these rocks? Why? 3 1 2 6 4 5