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1 – Rocks & Minerals 2 – Soil 3 – Landscape

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Presentation on theme: "1 – Rocks & Minerals 2 – Soil 3 – Landscape"— Presentation transcript:

1 1 – Rocks & Minerals 2 – Soil 3 – Landscape
Lithosphere 1 – Rocks & Minerals 2 – Soil 3 – Landscape

2 Lithosphere The lithosphere is a rigid part of the earth that includes the earth's crust and part of the upper mantle Ex. Mountains, plains, volcanoes, etc.

3 Lithosphere Thickness of the lithosphere varies from 70 km (under the oceans) to 150 km (under the continents) The lithosphere is essential to life: It allows plants to take root and provides them with the minerals they need to grow and develop It offers different habitats to animals It possesses various natural resources such as oil and natural gas and other materials needed for making objects in human life

4 Rock or Mineral? Mineral: Pure, natural and inorganic (non-living) substance. It is formed inside or on the surface of the earth's crust Rock: A heterogeneous assemblage of grains more or less varied and more or less large. Each of the grains is a mineral - There are many kinds of minerals in a rock

5 Rock or Mineral?

6 How Are Rocks Formed? There are three types of rocks, classified according to their origin. 1. Igneous rocks (igneus = fire): result of the cooling and the solidification of the magma 2. Sedimentary rocks: come from rock fragments (sediments) Due to erosion by water, wind and glaciers, rocks are fragmented, transported and deposited - Over time, fragments compact and cement into sedimentary rocks They sometimes contain fossils

7 How Are Rocks Formed? 3. Metamorphic rocks (meta = change, morphê = shape): rocks that have undergone a transformation. The transformation took place in the depths of the earth's crust, under the effect of heat and pressure

8 How Are Rocks Formed?

9 Igneous Rocks There are three types of igneous rocks
1. Intrusive (plutonic) igneous rocks: come from very slow cooling of magma inside the earth's crust They are formed of very large crystals visible to the naked eye Ex. granite, diorite and gabbro 2. Extrusive (volcanic) igneous rocks: form when a volcano spits lava that cools on contact with air or water Because of rapid cooling, crystals do not have time to develop and are microscopic Ex. obsidian, rhyolite, andesite and basalt

10 Igneous Rocks 3. Porphyritic rocks: have undergone two phases of cooling First phase: slow, in the depth of the earth's crust Second phase: faster, indicates that the rock has risen towards the surface, pushed by the magma The crystals are of variable size: the large crystals of the first phase are fixed in a mass of smaller crystals of the second phase Ex. some granites

11 Igneous Rocks

12 Sedimentary Rocks The frost, the action of glaciers or waves tear pieces of rocks from the earth's crust Rock fragments (sediments) are transported and polished by water, wind or landslides They are deposited in successive layers at the bottom of the seas and lakes Over time, sediments compact and cement to become sedimentary rocks

13 Sedimentary Rocks LIMESTONE SANDSTONE CONGLOMERATE

14 Fossils Fossils are sometimes found in sedimentary rocks
Fossil - Trace (imprint or remains) of an animal or plant that has been preserved in the rock of the earth's crust Over the years, the soft parts of plants or animals decompose and are replaced by minerals, which allow the rock to keep their shape The hard parts of the animal or plant (Ex. shell, tooth, etc.) sometimes remain intact

15 Fossils

16 Metamorphic Rocks Sometimes igneous, sedimentary rocks or even already formed metamorphic rocks undergo structural changes In the depths of the earth's crust, they transform under the action of pressure or heat They fold and deform as if they were made of modeling clay During this transformation, the minerals are rearranged into strips and sheets of varied textures

17 Metamorphic Rocks SLATE QUARTZITE MARBLE GRANITE TRANSFORMATION GNEISS

18 Metamorphic Rocks

19 Soil Soil: the surface layer (outside) of the earth's crust that allows, among other things, the growth of plants Soil is a vital element - Without soil, there will be no crops or livestock

20 The Formation of Soil The soil is formed from a hard rock that forms the earth's crust called the bedrock Two processes allowed soil formation: 1. Alteration of the bedrock 2. The supply of organic matter by living beings

21 The Formation of Soil Alteration of bedrock: corresponds to rock erosion due to erosion Caused, among other things, by the infiltration of water into the cracks of the bedrock. When the temperature drops below zero, the water freezes. As the volume of the ice is larger than the volume of the liquid water, the ice puts pressure on the walls of the crack and the rock is broken Acid in water also contributes to the disintegration of bedrock

22 The Formation of Soil The supply of organic matter by living beings:
This results from the accumulation of different debris. Debris of plant origin: leaves, fruits, pieces of bark, dead roots, etc. Debris of animal origin: feathers, hair, excrement, corpses, etc. By breaking down, debris forms humus Humus: A partially decomposed organic matter, of vegetable or animal origin

23 DEGRADATION OF BEDROCK
The Formation of Soil DECOMPOSTION OF ORGANIC DEGRADATION OF BEDROCK BEDROCK

24 Soil Profile The deeper we dig into the ground, the bigger the elements are The soil has several layers of different composition and structure called the three horizons of the soil: - The horizon A (or litter) - The horizon B - The horizon C (or subsoil)

25 Soil Profile Horizon A (ou litière) LITTER Horizon B
Horizon C (ou sous-sol) SUBSOIL

26 Soil Profile Horizon A (or litter)
Found on the surface. This is where debris of plant and animal matter turns into humus This horizon undergoes changes caused by water infiltration and is low in minerals because the rain carries them to the Horizon B by leaching Leaching: When a substance is dissolved and carried off by water

27 Soil Profile Horizon B The place where the leached minerals from the surface (horizon A) have accumulated There is little organic matter (living) but a lot of minerals. The rock is less fragmented than that of the horizon A Horizon C (or subsoil) The place where the bedrock is, the raw material of the other layers, partially degraded

28 Soil Texture & Structure
The texture of the soil depends on the size of the particles that compose it Soil is usually a mixture of three types of particles 1 – Sand 2 – Silt 3 – Clay

29 Soil Texture & Structure
The most fertile soils are the clayey loams Composed of clay and sand Contain enough fine particles to hold water and adhere minerals 1/3 sand (particles of over 50 micrometres) 1/3 silt (particles of 2 to 50 micrometres) 1/3 clay (particles of less than 2 micrometres)

30 Soil Texture & Structure
The soil structure indicates the arrangement of the elements Porosity: The percentage of free space in a given volume of soil Determines the ease with which soil allows water and air to flow Some soils have very large pores (spaces) for good gas and water circulation Other soils have finer pores, such as sponges, which retain some of the water

31 Soil Inhabitants The soil is protected from many different living organisms that determine soil properties Ex. Earthworms: aerate the soil by digging and secreting mucus that keeps soil particles together Ex: Bacteria: transform nitrogen in the atmosphere to make it more easily absorbed by plants Ex. Plant roots: absorb water and minerals dissolved in the soil, hold the soil in place and reduce the effects of erosion

32 Soil Inhabitants

33 Relief: The Evolution of the Landscape
Earth is always changing because of powerful forces: Large temperature differences cause wrinkles, uplifts and fractures of the Earth's crust These actions give the lithosphere different reliefs such as mountains, valleys, plains, etc. Winds, water and glaciers cause erosion, which rounds mountain tops and digs or fills valleys The human being builds roads, digs mines and builds towns and villages

34 Relief: The Evolution of the Landscape


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