Exogenic Processes PDF

Exogenic Processes TEACHER LARA Learning Objectives Describe how rocks undergo weathering; Identify the agents of erosion; and Explain how the products of weathering are carried away by erosion and deposited elsewhere.  Introduction The earth’s surface is composed of water and landmasses....

Exogenic Processes TEACHER LARA Learning Objectives Describe how rocks undergo weathering; Identify the agents of erosion; and Explain how the products of weathering are carried away by erosion and deposited elsewhere.  Introduction The earth’s surface is composed of water and landmasses. The solid portion is made out of rocks and minerals that could experience changes either physically or  Introduction The weathered materials are transported by different agents from one place to another and will settle down in a particular area. These progressions that happen is achieved by forms called exogenic processes. It includes weathering, erosion, Weathering Weathering is a process of breaking down rocks into small particles such as sand, clay, gravel and other fragments. There are two types of weathering: mechanical weathering and chemical weathering. Mechanical Weathering Mechanical weathering or physical weathering is the breakdown of rocks into pieces without any change in its composition. In this process, the size and shape of rocks changes and this occurs because of the  Mechanical Weathering Pressure Due to tectonic forces, granite may rise to form mountain range. After the granite ascends and cools, the overlying rocks and sediments may erode. At the point when the pressure diminishes, Mechanical Weathering Temperature Rocks expand and are fractured when exposed to high temperature. However, if the temperature drops to 0°C (freezing point of water), it also expands and causes fracture. Mechanical Weathering Frost Wedging Generally, rocks have fracture in its surface and when water accumulates in the crack and at that point freezes, the ice expands and breaks the rock apart.  Mechanical Weathering Abrasion The breakdown of rocks is caused by impact and friction. This primarily occurs during collision of rocks, sand, and silt due to current or waves along a stream or seashore causing sharp edges and corners to wear off and become Mechanical Weathering Organic Activities The roots grow causing penetration into the crack, expand, and in the long run, break the rock. Mechanical Weathering Human Activities Activities such as digging, quarrying, denuding forests and cultivating land contribute to physical weathering. Mechanical Weathering Burrowing Animals Animals like rats, rabbits and squirrels excavate into the ground to create a space for habitation. Chemical Weathering In chemical weathering, there are changes in the composition of rocks due to the chemical reactions.  Chemical Weathering Dissolution It occurs in specific minerals which are dissolved in water. Examples of these minerals are Halite(NaCl) and Calcite (CaCO3). The formation of stalactites and stalagmites in caves are brought about by this Chemical Weathering Hydrolysis Rock-forming minerals like amphibole, pyroxene, and feldspar react with water and form different kinds of clay minerals.  Chemical Weathering Oxidation It is the response of oxygen with minerals. If the iron oxidizes, the mineral in rocks decomposes. Rusting is an example of this chemical reaction.  Weathering Weathering is an important process in soil formation. Soil is a mixture of grains, organic matter, H2O, and gas. Plants, animals, and humans play an important role in the erosional process. Erosion is the separation and removal of weathered rocks due to different agents like water, wind, and glacier that causes transportation of the material to where they are deposited. Weathering The movement of sediments downslope under the influence of gravity is called mass wasting. The example of this are fall, slide, avalanche, and flow. On the other hand, deposition is the process in which the weathered materials carried out by erosion settle down in a particular location.  Weathering Alluvial Fans Reflect Upon How do animals cause erosion? How do human activities affect the rate of erosion? Reflect Upon What is the effect of soil erosion? What will you do to protect the community? Is erosion good or bad? References (2020) Earth and Life Science: Origin and Structure of the Earth – The Subsystem. Department of Education - Region IV-A CALABARZON