Unit 8H. The Rock Cycle

Transcription

1 Unit 8H The Rock Cycle Name:.. Year 8: 0

2 Sandstone becomes Quartzite Shale becomes Slate Limestone becomes Marble 1

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5 Examples of Rocks Schist Rocks: Schist rocks are metamorphic. These rocks can be formed from basalt (igneous rock), shale (sedimentary rock) or slate (metamorphic rock). Gneiss Rocks: Gneiss rocks are metamorphic rocks. These rocks have been granite (igneous rock). Grains in the rock flattened through tremendous heat and pressure. Conglomerate Rocks: Conglomerate rocks are sedimentary rocks. They are made up of large sediments like sand and pebble cemented together with dissolved minerals. Granite Rocks: Granite rocks are igneous which were formed by slowly cooling pockets of magma that were trapped beneath the earth s surface. Granite is used for long lasting monuments and decoration on buildings. Gypsum rocks: Gypsum rocks are sedimentary rocks formed as the result of evaporating sea water in massive prehistoric basins. It is very soft and is used to make Plaster of Paris. Limestone Rocks: Limestone rocks are sedimentary rocks that are made from the mineral calcite which came from the beds of evaporated seas and lakes and from sea animal shells. This rock is used in concrete and is an excellent building stone. Obsidian Rocks: Obsidian rocks are igneous rocks that form when lava cools quickly above ground. Obsidian is glass and not a mixture of grains. Shale Rocks: Shale rock is a type of sedimentary rock formed from clay that is compacted together by pressure. They are used to make bricks. Sandstone Rocks: Sandstone rocks are sedimentary rocks made from small grains of the minerals quartz and feldspars. They are often used as building stones. Pumice Rocks: Pumice rocks are igneous rocks which were formed when lava cooled quickly above ground. This rock is so light, that many pumice rocks will actually float in water. Pumice is actually a kind of glass and not a mixture of minerals. 4

6 Types of igneous rock: Intrusive and extrusive Sometimes magma cools below the Earth surface. This might happen in a volcano s side-vent (dyke). Sometimes liquid magma flows between rock strata and solidifies there, forming a sill. The molten rock is deep in the Earth, insulated from the cooler surface. This means it cools slowly. As it gradually solidifies, the mineral crystals have time to grow large before the rock becomes totally solid. Rocks formed like this are called intrusive igneous rocks. Other igneous rocks are formed on the surface of the Earth, so the lava cools quickly. There is no time for large crystals to form so these rocks have very small crystals or a glassy type of structure. Rocks formed like this are called extrusive igneous rocks. 5

7 Question 1: 1- Put the following sentences in order to show how sedimentary rocks are formed. 2- Complete the sentences. Grits and limestones are sedimentary rocks. One difference between them is the size of the grains: has larger grains than. They both have and. Sedimentary rocks contain the remains of living things. We call the remains. 3- The grains in sedimentary rocks do not fit closely together like the pieces of a jigsaw. a) Draw a few grains of limestone to show how they fit together. b) Label a grain and a pore. Question 2: Rocks can be changed 1- Complete the sentences. Meta means. Morph means. So rocks are rocks with a changed form. We call the process of change. 2- Complete the table. 6

8 3- Use the following words (heat, pressure, both heat and pressure) to complete the table below. Question 3: Volcanic eruptions Part one: Look at the lava lamp Complete the flow chart Part two: Use this model to explain how molten magma rises through the Earth s crust. 7

9 Question 4: Why does crystals size vary? 1- Use the words slowly and quickly to complete the table. 2- Match the way some rocks formed with their crystal size. 3- Match the crystal size with where the rocks cooled. 4- On your notebook, draw the shape of a volcano. a) In red, draw some lava running down the side of the volcano and some lava inside the volcano. b) Use a different colour to draw a cloud of ash coming out of the volcano. c) add these two labels in the correct places: lava cools quickly lava cools slowly 5- Look at the photos of granite and gabbro on page 94 then complete the sentences. Granite and gabbro are both igneous rocks because they have crystals. they formed deep below the Earth s surface because the crystals are. 8

10 Question 5: Building a rock cycle 9

11 Question 6: The rock cycle 10