The Lithosphere

1. The Lithosphere What are the different types of rock? How does the rock cycle affect different phenomena in our world?

2. The Lithosphere • The lithosphere is the rigid structure that makes up the Earth’s crust and part of the upper mantle. • It includes mountains, plains, volcanoes, etc. • It ranges in depth from 70 km (below the oceans) to 150 km (beneath the continents)

3. The Lithosphere • Very essential to life: • Enables plants to have roots • Provides plants with important minerals • Habitats for animals • Contains the natural resources we need • Provides the materials we need to build with

4. Rock or Mineral? • Rock: a heterogeneous blend of variously sized grains of different kinds • Mineral: a pure, natural, inorganic (non-living) substance. • Minerals are the building blocks of rocks.

5. Granite is a rock made of: The transparent crystals are quartz The grey pieces are mica The shiny grains are feldspar The dark spots are hornblende Four minerals = one rock!

6. Minerals • Minerals are inorganic substances which exist naturally in the Earth’s lithosphere. • Minerals have a distinct chemical composition:

7. Minerals can be made up of: • single elements (gold: Au, lead: Pb) • several elements bonded together (sodium chloride: NaCl, copper sulphate: CuSO4)

8. Mineral Classification • Minerals are classified based on their properties, which all minerals demonstrate: • Colour • Transparency • Hardness • Streak

9. Colour • Many minerals have a characteristic colour, caused by either the chemical composition of the mineral (idiochromatic) or by impurities in the sample (allochromatic). Rhodochrosite is red Azurite is blue

10. Clarity • Clarity is the property by which a substance allows light to pass through it. • Some let light pass straight through: transparent • Others let light through, but its impossible to distinguish the object through them: translucent • Others let no rays through at all: opaque

11. Hardness • Hardness depends on the strength of the atomic bonds: how hard the mineral is… • The Mohs scale assigns a value from 1 to 10 to indicate the hardness: 1 is soft, 10 is hard. • A mineral will scratch all softer minerals: a mineral with hardness 4 will scratch minerals of hardness 1, 2 and 3.

13. Streak • When a mineral is rubbed on a porcelain surface, it leaves a powder trace. This powder may be different from the colour of the mineral.

14. Minerals  Rocks • Minerals are combined together in various quantities to form rocks. • A rock is a heterogeneous solids composed of many minerals. • Rocks fall into three categories, depending on how they form: • Igneous • Sedimentary • Metamorphic

15. Types of rocks • 1) Igneous Rock • Igneous rock results from the cooling and solidification of magma. Granite Basalt Gabbro

16. 2) Sedimentary Rock • When igneous rocks break apart these fragments (called sediment) are then carried and polished by wind and water. • They are then deposited in layers at the bottom of oceans and lakes. • Over time, these layers are compacted and cemented together to form sedimentary rock.

17. Limestone

18. Sedimentary rock can contain fossils, which are the remains of plant or animal life. • Over time, the soft parts of animals are replaced by minerals, which causes the rock to retain the form of the animal. • Sometimes, we can find intact bones or teeth! A cockroach fossil in sandstone

19. 3) Metamorphic Rock • When igneous and sedimentary rocks are pressed really hard or heated, the minerals are rearranged. They settle in bands or sheets, or change their texture. • This process creates metamorphic rock.

20. Slate

21. Summary!

22. Gneiss has light and dark bands Mica schist has rigid bands

23. Crystals or bands? Gneiss has colored bands Granite has crystals