Module 1: Weathering PDF

GRADING SYSTEM WRITTEN WORKS-25% PERFORMACE-50% PERIODICAL TEST-25% RULES AND REGULATIONS: Raised hand to speak Finished output, always do your best. Submission of output Your reflection Quarter 2 Module 1: Weathering  After going through this lesson, After going through this lesson,...

GRADING SYSTEM WRITTEN WORKS-25% PERFORMACE-50% PERIODICAL TEST-25% RULES AND REGULATIONS: Raised hand to speak Finished output, always do your best. Submission of output Your reflection Quarter 2 Module 1: Weathering  After going through this lesson, After going through this lesson, you are expected to: you are expected to: 1. identify the different agents of weathering; 2. identify the different types of physical, chemical, and biological weathering; 3. describe physical, chemical, and biological weathering; and 4. explain how rocks undergo weathering WHAT DO YOU MEAN BY WEATHERING? WEATHERING Weathering is the process of breaking down rocks present at Earth’s surface. Weathering can happens in the presence of the action of rainwater, variable extreme temperature, and different biological activities. physical weathering, chemical weathering, and biological weathering. AGENTS OF WEATHERING 1. Water One of the agents of mechanical weathering. In liquid form, it seeped into cracks and crevices of rocks and when the temperature dropped, it freezes and definitely will expand in the form of ice. 2. SALT Haloclasty is a type of weathering where salts act as the agent. Saltwater enters cracks and pores of rocks, and when the water evaporates, salt crystals form. 3. TEMPERATURE Thermal stress causes weathering as rocks expand with heat and contract with cold. Over time, repeated temperature changes weaken the rock, leading it to crumble. 4. PLANTS The roots grow causing penetration into the crack, expand, and in the long run, break the rock. 5. ANIMALS Animals like rats, rabbits and squirrels excavate into the ground to create a space for habitation. TYPES OF WEATHERING  Physical Weathering  Chemical Weathering  Biological weathering A. PHYSICAL / MECHANICAL WEATHERING Mechanical weathering is a process wherein rocks are broken down into smaller pieces without changing their chemical composition due to several factors like fluctuating temperatures and pressure, and biological activity. TYPES OF MECHANICAL WEATHERING 1. Frost wedging is a process that involves repeated cycles of freezing and thawing of ice. It happens when there is sufficient moisture; pre- existing cracks; and when temperatures frequently Weathering of rocks through frost wedging rise and fall 2. EXFOLIATION is a type of physical weathering that involves the peeling or flaking away of the outer layers of rock. This process typically occurs due to changes in temperature and pressure. Here’s how it works:  3. Granite Domes: One of the most famous examples of exfoliation is found in granite formations, such as Half Dome in Yosemite National Park, where the outer layers have weathered away, revealing the smooth, rounded core  4. ABRASION is a type of physical weathering that occurs when rocks and particles wear away surfaces through friction and impact. This process often involves the following mechanisms: B. CHEMICAL WEATHERING Chemical weathering is a process wherein rock materials are changed into other substances that have different physical and chemical compositions. Chemical weathering TYPES OF CHEMICAL WEATHERING 1. Carbonation Carbon dioxide in the air dissolves in rainwater and becomes weakly acidic. This weak “carbonic acid” can dissolve limestone as it seeps into cracks and cavities. 2. HYDROLYSIS the breakdown of rock by acidic water, resulting in the formation of clay and soluble salts. This process occurs when acid rain reacts with minerals like feldspar, producing clay and salts that are washed away in solution. 3. HYDRATION a type of chemical weathering where water reacts chemically with the rocks, modifying its chemical structure. Example: H2O (water) is added to CaSO4 (calcium sulfate) to create CaSO4 + 2H2O (calcium sulfate dihydrate). It changes from anhydrite to gypsum. 4. OXIDATION the breakdown of rock by oxygen and water, often giving iron- rich rocks a rusty-colored weathered surface.  C. BIOLOGICAL WEATHERING Biological weathering of rocks occurs when rocks are weakened by different biological agents like plants and animals. BIOLOGICAL WEATHERING BY PHYSICAL MEANS. Burrowing animals like shrews, moles, and earthworms excavate the ground, creating holes and bringing rock fragments to the surface. This exposure increases the fragments' vulnerability to environmental factors that enhance weathering. Additionally, human activities also contribute to biological weathering by causing rocks to break apart. BIOLOGICAL WEATHERING BY CHEMICAL COMPOUNDS. Some plants and animals also produced acidic substances that react with the rock and cause its slow disintegration. FACTORS AFFECTING WEATHERING OF ROCKS Climate mainly includes the amount of moisture in the air and temperature where weathering takes place. The higher the elevation of an area, the more susceptible it is to weathering since it is more exposed to environmental factors. FACTORS AFFECTING WEATHERING OF ROCKS Weathering rapidly occurs when there is a large surface area exposed to surface processes. When a block is broken into smaller pieces, it has a larger total surface area which makes it more susceptible to weathering. A block that is broken into smaller pieces has a higher total surface area. FACTORS AFFECTING WEATHERING OF ROCKS Goldich stability series illustrates the relative stability or weathering rate of numerous minerals. This series is roughly the inverse order of original crystallization for minerals found in the Bowen’s reaction series. Goldich stability series  Weathering is the breaking down of rocks either mechanically or 1 chemically. Weathering of rocks is caused by numerous factors such as 2 climate, surface area and topographic relief, and rock composition. 3 Weathering can either be in the form of chemical or mechanical weathering. Any question/ clarification? WRITE TRUE IF THE STATEMENT IS CORRECT, AND FALSE IF THE STATEMENT IS INCORRECT. 1. Frost wedging is an example of mechanical weathering. 2. Karst topography is a landscape formed by the dissolution of carbonate rocks. 3. Weathering slowly occurs when there is a large surface area exposed to surface processes. 4. Hydroglyphics is a process wherein water reacts with a mineral to form a new mineral. 5. Dissolution refers to a process where erosion removes the thick layers of sediments overlying deeply buried rocks. LET US CHECK! WRITE TRUE IF THE STATEMENT IS CORRECT, AND FALSE IF THE STATEMENT IS INCORRECT. 1. Frost wedging is an example of mechanical weathering. True 2. Karst topography is a landscape formed by the dissolution of carbonate rocks. True 3. Weathering slowly occurs when there is a large surface area exposed to surface processes. False 4. Hydroglyphics is a process wherein water reacts with a mineral to form a new mineral. False 5. Dissolution refers to a process where erosion removes the thick layers of sediments overlying deeply buried rocks. False  What are the types of weathering? Give at least types of chemical weathering? WHICH TYPE OF WEATHERING WOULD PRODUCE MORE SEDIMENTS, MECHANICAL WEATHERING OR CHEMICAL WEATHERING?