LESSON 3 - ELS.pdf

Rock Formation  explain how rocks undergo Objectives 1 change using the rock At the end cycle; and of the lesson, you describe the formation of should be 2 the igneous, sedimentary, able to: and metamorphic rocks.  Learn about It! Rock A rock i...

Rock Formation  explain how rocks undergo Objectives 1 change using the rock At the end cycle; and of the lesson, you describe the formation of should be 2 the igneous, sedimentary, able to: and metamorphic rocks.  Learn about It! Rock A rock is an aggregate of mineral or minerals which may or may not contain organic matter. Geosphere is made out of rocks. Sandstone  Learn about It! Rock Cycle Rock cycle is a model used to describe how rocks are formed, broken down, and reformed into other types of rocks. Any types of rock can be a raw material of another rock. The Rock Cycle  Learn about It! Three Types of Rock Rocks are classified into three types: ○ Igneous rocks are formed from cooling of molten magma. ○ Sedimentary rocks are formed from pre-existing rocks and fossils of organisms. ○ Metamorphic rocks are formed from pre-existing rocks through heat and pressure.  Learn about It! Formation of Igneous Rock It is formed from the cooling of magma or lava. It can classify into intrusive and extrusive. ○ Intrusive igneous rocks are formed in Earth’s interior wherein cooling rate is slower resulting in large crystal formation. ○ Extrusive igneous rocks are formed in Earth’s surface where the cooling rate is faster resulting in smaller crystal formation.  Learn about It! Formation of Igneous Rock Quenching It is where molten rock is cooled instantly which may result in rock with glassy like texture example of this, volcanic glass and obsidian. This process usually happens in a violent volcanic eruption. Obsidian  Learn about It! Formation of Igneous Rock It can also be divided into groups according to mineral content: ○ Felsic or Granitic rocks are rocks that are generally composed of light-colored minerals ○ Basaltic or Mafic rocks that are composed of dark grey to black minerals.  Learn about It! Formation of Sedimentary Rock Sedimentary rocks are formed from pre-existing rocks and fossils of organisms. Pamukkale  Learn about It! Formation of Sedimentary Rock There are several processes involved in the formation of sedimentary rock. Weathering is a process of breaking down rock into smaller pieces it can be physical or chemical. Erosion is a process of transferring unconsolidated Earth’s material via agents like human, animal, wind, and water.  Learn about It! Formation of Sedimentary Rock Deposition occurs when all the unconsolidated materials settle in one area. Lithification takes place when sediments turns into sedimentary rock. It involves the processes of compaction and cementation.  Learn about It! Formation of Metamorphic Rock Metamorphic rock can classify according to its foliation. Foliation refers to the sub-planar orientation of mineral grains or the layering found in the rocks. Fig. 5 Slate  Learn about It! Formation of Metamorphic Rock There are two types of metamorphic rock: ○ Foliated metamorphic rocks have clear layers which are formed in areas where rocks are deformed by stresses like plate boundaries. ○ Non-foliated metamorphic rocks have no definite layers which are formed in areas where deformation is minimal. Key Points A rock is an aggregate of mineral or minerals which 1 may or may not contain organic matter. 2 The rock cycle is a model that shows how each type of rock is formed from each other. The three types of rocks are igneous, sedimentary, 3 and metamorphic rocks. Key Points Igneous rocks are formed from cooling of molten 4 magma. Sedimentary rocks are formed from pre-existing 5 rocks and fossils of organisms. Metamorphic rocks are formed from pre-existing 6 rocks through heat and pressure. Rock-Forming Minerals Let’s Think! Do you consider water a mineral? Let’s Think! How about snowflake, or tube ice? Are these minerals?  identify common rock- Objectives forming minerals using 1 their physical and At the end chemical properties; of the and lesson, you should be identify the minerals able to: 2 important to society.  Learn about It! Minerals It is a naturally occurring, inorganic, homogeneous solid, with a definite chemical composition, and an ordered crystalline structure. Example of a mineral  Learn about It! Physical Properties of Minerals Color refers to certain wavelengths of light that are reflected by a mineral and is perceived by the observer. Streak is the color of the powdered form of a mineral. Luster is the appearance of a mineral’s surface and is dependent on how it reflects light. Crystal habit is the characteristic shape in which a mineral grows and is a projection of the mineral’s crystal structure.  Learn about It! Physical Properties of Minerals Cleavage is the tendency of some minerals to break along flat surfaces. Fracture is the pattern in which the mineral breaks aside from its planes of cleavage. Hardness is the resistance of the minerals to scratching. Specific gravity is the ratio of a minerals’ weight to the weight of an equal volume of water.  Learn about It! MOHS SCALE OF HARDNESS  Learn about It! Chemical Properties of Minerals Solubility refers the ability of a substance to dissolve in a solvent at a specified temperature. Melting point refers to the temperature at which solid turns into liquid.  Learn about It! Mineral Groups Based on Chemical Composition Chemical Example Description structure Minerals Elements Most of the minerals here are composed of only one element. copper, gold, silver, Having knowledge about elements enables scientists to identify sulfur bonding possibilities and compounds that can be created. Sulfides Minerals under these group are composed of a metal joined by cinnabar (HgS), a sulfur. Metallic luster is the characteristic that distinguish pyrite (FeS2) them. Halides These are nonmetal groups which consists of chlorine, fluorine, fluorite (CaF2), halite bromine, and iodine as their main chemical constituent. (NaCl), diabolite  Learn about It! Mineral Groups Based on Chemical Composition Chemical Example Description structure Minerals Oxides and These are mineral groups composed of one or more metals cuprite (Cu2O), hydroxides joined with oxygen, water, or hydroxyl (OH) hematite (Fe2O3) Nitrates, It is formed when a metal is combined with carbon, nitrogen malachite, carbonates, and boron. nitratine, borax borates Sulfates One or more metal is combined with a sulfate compound anhydrite (CaSO4) (SO4)  Learn about It! Analysis of the Composition and Crystal Structure of Minerals Wet chemical analysis involves dissolving a mineral in an acid and analyzing the solution.  Learn about It! Analysis of the Composition and Crystal Structure of Minerals Spectroscopic techniques involve quantitative analysis of mineral components depending on the light absorbance of the compounds. Spectrophotometer Key Points A mineral is a naturally occurring, inorganic, solid 1 material that has definite chemical composition. The physical properties of minerals are color, streak, luster, crystal habit, cleavage, fracture, 2 hardness, and specific gravity. These properties are used for mineral identification. Solubility and melting point are chemical 3 properties commonly used to describe a mineral.  Check Your Understanding Write true if the statement is correct. Otherwise, write false. 1. A mineral is a naturally-occurring substance. 2. Talc can scratch diamond. 3. A huge/hard mineral has high specific gravity. 4. Quartz is a good example of an idiochromatic mineral. 5. Allochromatic minerals are false-colored minerals.  Try it! 1. How do you classify igneous rock according to mineral content? 2. Physical property of rock that is more reliable than color 3. What acid is used for wet mechanical analysis of mineral? 4. Give one example of spectroscopic technique 5. Differentiate deposition from lithification. Igneous Rocks  Learn about It! Igneous Rocks Igneous rocks are formed from solidification of magma or lava which flows out from depth. Minerals such as quartz, feldspar, pyroxene, olivine, amphibole, and mica are the components of almost all types of igneous rocks. Example of Igneous Rock  Learn about It! Formation of Igneous Rock Igneous rocks are characterized by intergrowth of crystals and/or volcanic glass. Crystal size is directly proportional to the cooling rate of magma.  Learn about It! Formation of Igneous Rock Big crystals are formed deep underground, while smaller crystals are formed near the surface. Cooling and crystal formation  Learn about It! Types of Igneous Rocks An extrusive igneous rock forms when magma or volcanic fragments erupt and solidify on Earth’s surface which results to very fine-grained rock with very small crystals that could not be seen through naked eye. Example of Extrusive Igneous Rock  Learn about It! Types of Igneous Rocks An intrusive igneous rock forms when magma crystallizes within the crust and is composed of medium to coarse grains. It is also known as a plutonic rock. Formation of Intrusive Igneous Rock Key Points Igneous rock is formed from solidification of 1 magma or lava which flows out from depth. Igneous rocks can be classified based on the 2 temperature-pressure condition. Bowen’s reaction series shows the progression of 3 silicate minerals crystallization at specific temperature condition.  Challenge Yourself By just observing a rock sample, how would you know if it is an intrusive or extrusive rock? Sedimentary Rocks  identify and differentiate Objectives 1 the types of sedimentary rocks; and At the end of the describe the origin and lesson, you environment of should be 2 formation of able to: sedimentary rocks.  Learn about It! Sedimentary Rocks Sedimentary rocks were formed from organic, mechanical or chemical sediments. A process called lithification is where harden sediments become sedimentary rocks. Example of Sedimentary Rocks  Learn about It! Formation of Sedimentary Rock Diagenesis is a collective process where sediments are lithified (becomes rock). It has four main parts: Compaction Cementation Recrystallization Chemical changes (oxidation/reduction)  Learn about It! Types of Classification of sedimentary rocks based on particle size. Sedimentary Rock Texture (grain size) Sediment name Rock name gravel (rounded Clastic sedimentary coarse fragments) conglomerate rocks are made up of (over 2 mm) gravel (angular sediments from fragments) breccia preexisting rocks. medium sand sandstone (1/16 to 2 mm) fine silt siltstone (1/16 to 1/256 mm) very fine (less than 1/256 clay shale mm)  Learn about It! Types of Sedimentary Rock Examples of non-clastic sedimentary Biological rocks sedimentary rocks are Composition Texture (grain size) Rock Name lithified accumulation of chert (light color) dead organisms. quartz very fine crystalline flint (dark color) dine to coarse gypsum rock gypsum Chemical sedimentary crystalline rocks form from halite fine to coarse rock salt chemical precipitation crystalline altered plant fine-grained organic bituminous coal fragments matter  Learn about It! Types of Sedimentary Rock Non-clastic sedimentary rocks can be biological, chemical, or a combination of both. Key Points Sedimentary rocks are formed by the compaction 1 and cementation of sediments, a process called lithification. Sedimentary rocks are classified into clastic or non- 2 clastic. Metamorphic Rocks  identify and differentiate Objectives 1 the types of metamorphic rocks; and At the end of the describe the origin and lesson, you environment of should be 2 formation of able to: metamorphic rocks.  Learn about It! Metamorphic Rocks Metamorphic rocks are rocks that have been altered, changed, or transformed in the solid state due to changes in pressure, temperature conditions, and chemical actions of hot fluids. Examples of metamorphic rock  Learn about It! Formation of Metamorphic Rock Metamorphism is like the chameleon changing its color to protect itself by blending into its environment. The goal of metamorphism is like the chameleon which is to reestablish equilibrium with the new conditions.  Learn about It! Formation of Metamorphic Rock Changes in minerals during metamorphism can happen in three possible ways. 1. Recrystallization occurs when small crystals of one mineral will slowly convert to fewer, larger crystals of the same mineral without melting the rock.  Learn about It! Formation of Metamorphic Rock 2. Neomorphism is the process whereby minerals not only recrystallize, but also form different minerals from the same chemical elements. 3. Metasomatism is the the addition or loss of elements new minerals form with only some of the original elements.  Learn about It! Types of Metamorphic Rock Contact metamorphism occurs only at a local area adjacent to large intrusions and along fractures that are in contact with hot fluids. Contact metamorphism.  Learn about It! Types of Metamorphic Rock Regional metamorphism occurs when there are major igneous intrusions, presence of extreme pressure and heat due to deep burial. Regional metamorphism.  Learn about It! Types of Metamorphic Rock Foliated metamorphic rocks are formed when parallel planes of platy or elongated minerals creating what is called as foliations. Increasing metamorphism causes distinct bands or foliation to form.  Learn about It! Types of Metamorphic Rock Nonfoliated metamorphic rocks do not have layered appearance. Examples are marble, quartzite, and anthracite. Some metamorphic rocks with their corresponding protoliths.  Learn about It! Rock Cycle The rock cycle shows that all rocks are related to each other. Igneous rocks can change into sedimentary or metamorphic rocks. Rock Cycle  Learn about It! Rock Cycle The rock cycle shows that all rocks are related to each other. Sedimentary rocks may also transform into igneous or metamorphic rocks. Rock Cycle  Learn about It! Rock Cycle The rock cycle shows that all rocks are related to each other. Metamorphic rocks can change into the all the three rock types. Rock Cycle  Learn about It! 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 Key Points Metamorphic rocks are rocks that have been 1 altered, changed or transformed in the solid state. Recrystallization, neomorphism and 2 metasomatism are the three ways of metamorphism. The rock cycle shows that all rocks are related to 3 each other.  Learn about It! What do you mean by the statement, “One rock is the raw material for the other?” 2. What is the difference between regional and contact metamorphism? 3. How do you distinguish metamorphic rock from the other two types? Weathering  describe how rocks 1 undergo weathering; Objectives differentiate mechanical At the end 2 weathering and chemical of the weathering; and lesson, you should be enumerate the factors able to: 3 that contribute to weathering.  Learn about It! 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.  Learn about It! 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. Rocks by the sea change shape due to the force of water during high tide.  Learn about It! Types of Mechanical Weathering 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 rise and fall Weathering of rocks through frost wedging  Learn about It! Types of Mechanical Weathering Salt crystal growth is a process that happens when seawater penetrates crevices in rocks which are found mostly in rocky shorelines and arid regions. Salt crystals expand when subjected to an increase in temperature that causes the widening of cracks. Rock weathering in beaches  Learn about It! Types of Mechanical Weathering Biological activity is the action of organisms including plants and animals reduces the size of rocks and minerals which make rocks more susceptible to chemical weathering. Weathering by roots of plants  Learn about It! Types of Mechanical Weathering Unloading happens through erosion or uplift, thick layers of sediments overlying deeply buried in rocks are removed. This process is termed unloading. Unloading of rocks  Learn about It! Chemical Weathering Chemical weathering is a process wherein rock materials are changed into other substances that have different physical and chemical compositions. Chemical weathering  Learn about It! Types of Chemical Weathering Dissolution is a process wherein a solid (i.e., halite) dissolves in a liquid (i.e., water). Hydrolysis is a process where water reacts with a mineral to form a new mineral. Oxidation is a where chemical combination of oxygen with a mineral to form an entirely different mineral in which at least one of the elements has a higher ionic charge.  Learn about It! 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.  Learn about It! 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.  Learn about It! 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 Key Points Weathering is the breaking down of rocks either mechanically 1 or chemically. Weathering of rocks is caused by numerous factors such as 2 climate, surface area and topographic relief, and rock composition. Weathering can either be in the form of chemical or 3 mechanical weathering.  Check Your Understanding 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.  Challenge Yourself Which type of weathering would produce more sediments, mechanical weathering or chemical weathering? Erosion  Learn about It! Erosion Erosion is the transportation of weathered rocks. Agents like running water or rivers, wind, gravity, groundwater, wave currents, and glaciers contribute to erosion. Erosion has different types: water erosion, wind erosion, and glacial erosion.  Learn about It! Types of Erosion Water erosion is a type of erosion where water carries the sediments to different bodies of water such as rivers. The high amount of rainfall contributes to susceptibility of the soil to water erosion. Grand Canyon in Arizona, a product of water erosion  Learn about It! Types of Erosion Wind erosion happens when light materials, such as small rocks and pebbles, are carried by the wind to different places. Rock shaped by wind erosion  Learn about It! Types of Erosion Glacial erosion happens when a glacier, or a river of highly-compact ice, move downhill due to its weight. It plucks chunks of rocks and causes scraping between the ice and the rock. Landform formed by glacial erosion  Learn about It! Causes of Erosion Soil erodibility is the vulnerability of soil to erosion caused by rainfall intensity, soil properties, crop cover, and slope. The texture of the soil is the most significant contributing factor to erodibility although structure, organic matter, and permeability may also affect it.  Learn about It! Causes of Erosion Overgrazing by livestock or by indigenous animals may remove vegetation leaving the soil more vulnerable to erosion. Overgrazing  Learn about It! Causes of Erosion Cutting of trees and removal of vegetation to provide lumber can also result in large amounts of erosion. Use of pesticides, herbicides, and fuel oils also pollutes the soil. Salt can also contaminate soil due to the high salinity of irrigation water as it passes over croplands.  Learn about It! Preventing Soil Erosion Steep terrains are shaped to produce flat areas Reducing farmland conversion Planting vegetation Application of organic fertilizer Building retaining walls Rice Terraces Key Points Erosion is the movement of sediments and particles through 1 the help of transporting media such as glacial ice, water, and wind. Erosion has different types: water erosion, wind erosion, and 2 glacial erosion. 3 Soil erosion can be affected by several external factors.  Photo Credits Slide 4: This file, Puerto Princesa Underground River by Mike Gonzalez is licensed under CC-BY-SA 3.0 via Wikimedia Commons. Slide 6: This file, Tafoni 03 by Dawn Endico is licensed under CC-BY-SA 2.0 via Wikimedia Commons. Slide 7: This file, High rocks on top tree roots 4126 by Clem Rutter is licensed under CC-BY-SA 3.0 via Wikimedia Commons. Slide 8: This file, Granite exfoliation- Flickr- S. Rae by S. Rae is licensed under CC-BY-SA 2.0 via Wikimedia Commons.  Bibliography Amethyst Galleries Inc. “Mineral Gallery” Accessed April 5, 2018. http://www.galleries.com/default.htm Coenraads, Robert R. 2005. Rocks & Fossils: A Visual Guide. Australia: Weldon Owen Inc. Tarbuck, Edward J. and Frederick J. Lutgens. 2012. Earth Science, 13th Edition. New Jersey: Pearson Prentice Hall. Thompson, Graham R. and Jonathan Turk. 1997. Introduction to Physical Geology. United States: Brooks Cole Publishing. Williams, Linda. 2004. Earth Science Demystified. United States: The McGraw -Hill Companies, Inc.