Earth Science 2nd Quarter Past Paper PDF

Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 1 : WEATHERING WEATHERING Weathering is often divided into the process of mechanical weathering and chemical weathering. BIOLOGICAL WEATHERING : in which living or non-living organisms contribute...

Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 1 : WEATHERING WEATHERING Weathering is often divided into the process of mechanical weathering and chemical weathering. BIOLOGICAL WEATHERING : in which living or non-living organisms contribute to weathering. MECHANICAL / PHYSICAL WEATHERING A. DEEPLY BURIED IGNEOUS PLUTON : Process by which rocks break down into Pluton refers to a large, intrusive body of smaller pieces by physical means. igneous rock that is buried deep underneath Strictly a physical process and does not the Earth’s surface. The overlying pressure change the chemical composition of the exerted by the rocks above it, called rocks confining pressure. Caused by the effects of changing B. UPLIFT AND EROSION OF temperatures on rocks, causing the rocks OVERLYING ROCK : Overtime, due to to break apart. tectonic forces, when the pluton is uplifted WHERE : It happens especially in places to the surface of the Earth, the confining where there is little soil and few plants pressure is released. Due to the release, it grow, such as in mountain regions and hot expands outwards in all directions, deserts. It can also include cold tundras. increasing in volume. This increasing It occurs through repeated melting and volume is greater than the strength of the freezing of water. overlying rock and so the rock tends to Expansion and contraction of the surface break in a series of fractures that are layer of rocks that are baked by the sun (hot perpendicular to the expansion deserts). direction, causing onion-like sheets of rock EXAMPLES OF MECHANICAL OR to form. PHYSICAL WEATHERING 1. Abrasion 2. Exfoliation / Sheeting ICE WEDGING 3. Ice Wedging Occurs when water seeps into cracks in rock and then freezes. ABRASION WHERE : Commonly occurs at high elevations and in cold climates. Collision of rocks that result in the Water flows into a crack in a rock’s surface. breaking and wearing away of rocks. When the water freezes, it expands and Caused by : causes the crack to widen. - Gravity - Ice - Running water - Wind EXFOLIATION / SHEETING Process in which large flat or curved sheets of rock fracture and are detached from the outcrop due to pressure release. 1 Earth Science 1ST SEMESTER - 2ND QUARTER CHEMICAL WEATHERING Process by which rocks are broken down because of chemical interactions within the environment. Also known as decomposition, occurs when chemical reactions act on the minerals in a rock. Chemical reactions commonly occur between : - Rock - Water - Carbon Dioxide - Oxygen - Acids EXAMPLE : A type of feldspar combines Chemical reactions with other acids or with water and produces a common clay bases can change the structure of the called kaolin. minerals, which leads to the formation of In this reaction, hydronium ions displace new minerals. the potassium and calcium atoms in the EXAMPLES OF CHEMICAL feldspar crystals, which changes the WEATHERING feldspar into clay. 1. Oxidation 2. Hydrolysis 3. Carbonation 4. Organic Acids 5. Acid Precipitation OXIDATION Process by which elements combine with Minerals that are affected with hydrolysis oxygen. often dissolve in water. Iron bearing minerals oxidize commonly. LEACHING : process by which water Examples include hematite and magnetite. carries the dissolved minerals to lower layers of rock. Ore deposits, such as bauxite, the aluminum ore, are formed. In this rock, Iron (Fe), combines quickly with Oxygen (O2), which is dissolved in CARBONATION water to form rust, or Iron Oxide (FeO). Conversion of a compound into a carbonate. HYDROLYSIS When Carbon Dioxide (CO2), from the air dissolves in Water (H2O), a weak acid Chemical reaction between water and called Carbonic Acid, H2CO3 forms another substance to form two or more new substances. The change in the composition of minerals when they react chemically with water. Rain, weak acids, and air chemically Carbonic acid seeps through the ground weather a rock. and dissolves certain minerals. The bonds between the mineral grains in LIMESTONE FORMATION : calcite is the rock are weakened by the chemical carbonized to form calcium bicarbonate due weathering. to calcite reacting with carbonic acid. Sediment forms from the weathered rock. 2 Earth Science 1ST SEMESTER - 2ND QUARTER Calcium bicarbonate dissolves easily in EXAMPLES OF BIOLOGICAL water, so the limestone eventually WEATHERING weathers away. 1. Biological weathering by Physical means (burrowing animals). 2. Root wedging 3. Biological breakdown LESSON 2 : MAGMA ENDOGENIC PROCESS Is an internal geomorphic process. GEOMORPHIC PROCESS : are changes in the configuration of the Earth’s surface. MAGMA Molten and semi-molten rock mixture found under the surface of the Earth. ORGANIC ACIDS Hot viscous material that consists of Acids that are produced naturally by inorganic components such as : certain living organisms. - MELT : hot liquid base Lichens and mosses that grow on rocks - Minerals can produce weak organic acids that can - Solid rocks weather the surface of the rock. - Dissolved gases VISCOSITY : property of magma that describes a fluid. ACID PRECIPITATION Nitrogen oxides (NO) and sulfur dioxide MAGMA CHAMBERS (SO2) are released into the air due to burning of coal. Magma often collects in magma chambers These compounds combine with water that may feed a volcano or solidify in the atmosphere to produce : underground to form an intrusion. 1. Nitric acid 2. Nitrous acid TYPES OF IGNEOUS ROCKS 3. Sulfuric acid Acidic gases are released into the EXTRUSIVE / INTRUSIVE / atmosphere. (NO and SO2) VOLCANIC PLUTONIC Gases are carried by the wind and dissolve in rain water to form acid rain Cool quickly Cools slowly (Nitric acid, nitrous acid, sulfuric acid). Fine grained Coarse grained Acid rain kills plantlife, pollutes rivers and Lack crystal Has crystal streams, and erodes stonework. growth growth BIOLOGICAL WEATHERING COMPOSITION OF MAGMA Occurs when rocks are weakened by different biological agents like plants and Controlled by the abundance of elements animals. in the Earth. Silicon (Si), Aluminum (Al), Iron (Fe), Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na), Hydrogen (H), and Oxygen (O) make up 99.9% 3 Earth Science 1ST SEMESTER - 2ND QUARTER TYPES OF MAGMA BASALTIC / MAFIC MAGMA FELSIC / RHYOLITIC MAGMA Silicon Dioxide (SiO2) : 45-55 wt% Silicon Dioxide (SiO2) : 65-75 wt% HIGH in Iron (Fe), Magnesium (Mg), LOW in Iron (Fe), Magnesium (Mg), Calcium (Ca). Calcium (Ca). LOW in Sodium (Na), and Potassium (K). HIGH in Sodium (Na), and Potassium (K). LOW in gas content. HIGH in gas content. LOW in viscosity. HIGH in viscosity. HIGH in temperature. LOW in temperature. SOLIDIFIED VOLCANIC ROCK (Extrusive SOLIDIFIED VOLCANIC ROCK (Extrusive Igneous Rock) : Basaltic Igneous Rock) : Rhyolite SOLIDIFIED PLUTONIC ROCK (Intrusive SOLIDIFIED PLUTONIC ROCK (Intrusive Igneous Rock) : Gabbro Igneous Rock) : Granite ANDESITIC / INTERMEDIATE MAGMA Silicon Dioxide (SiO2) : 55-65 wt% INTERMEDIATE in Iron (Fe), Magnesium (Mg), Calcium (Ca), Sodium (Na), Potassium (K), gas content, viscosity, and temperature. SOLIDIFIED VOLCANIC ROCK (Extrusive Igneous Rock) : Andesite SOLIDIFIED PLUTONIC ROCK (Intrusive Igneous Rock) : Diorite 4 Earth Science 1ST SEMESTER - 2ND QUARTER DECOMPRESSION MELTING FORMATION OF MAGMA WHAT : Melting due to decrease in pressure. WHY : Melting takes place within Earth PARTIAL MELTING when a body of rock is held at WHAT : Happens when only some parts of approximately the same temperature but a rock melt. the pressure is reduced. WHY : Rocks contain different minerals in Happens because the rock is being moved their composition, each made up of various towards the surface either : chemical elements. These minerals have a. At a mantle plume different melting temperatures. b. Upwelling part of a mantle Minerals with higher melting convection cell. temperatures remain solid, due to the heat that causes it to melt does not surpass its high melting temperature. This means that a higher temperature of heat is required for the mineral to melt, compared to minerals with lower melting temperatures. Minerals with lower melting temperatures melt, due to the heat that causes it to melt easily surpasses its low melting temperature. The magma that forms then moves upward from the mantle and can go all the way through the crust. The rifting movement causes the buoyant On its way up, it encounters other rocks magma below to rise and fill the space of through the mantle and crust layer. The low pressure. heat that emanates off of the magma The rock then cools into a new crust. transfers to the rocks. This causes the In this phase diagram, decompression components of these rocks with lower melting is shown if a rock that is hot melting temperatures than the temperature enough to be close to its melting point is of the magma will start melting and join the moved towards the surface. magma flow. The pressure is reduced, and the rock can WHERE : Upper mantle or the crust pass to the liquid side of the melting curve. At this point, partial melting takes place. WHERE : Divergent plate boundaries, where tectonic plates separate 5 Earth Science 1ST SEMESTER - 2ND QUARTER TRANSFER OF HEAT WHAT HAPPENS AFTER MAGMA IS FORMED WHAT : Magma can also be created when At very high temperatures (over 1300°C), hot, liquid rock intrudes into Earth’s cold most magma is entirely liquid. crust. As the magma continues to cool, crystals WHY : When continental and oceanic start to form. plates collide, the thinner and more dense Silicon and oxygen in the magma combine oceanic plate is overridden by the to form silica tetrahedra (SiO4-4), and then, thicker and less dense continental plate. as cooling continues, the tetrahedra start to SUBDUCTION : the oceanic plate is forced link together to make chains down into the mantle. (polymerize). Hot rock from below can intrude into the As the magma cools, the atoms move cooler plate above. This process slower and are more likely to form bonds transfers heat and creates magma. with other atoms. The silica tetrahedra can WHERE : Convergent plate boundaries, link together by sharing oxygen atoms, where tectonic plates are crashing together. forming chains or networks. Occurs at the same place as flux melting. Silica tetrahedra (monomers), link up This is due to the water from the oceanic together to make chains (polymerize) to crust that subducts lowers the melting form polymers which form various silica temperature of the rocks, causing it to materials such as quartz, feldspar, mica, melt. etc. Magma leaves the confines of the upper mantle and crust in two major ways FLUX MELTING a. Intrusion WHAT : Occurs when water or carbon - Dikes (magma that solidified dioxide (fluxes) are added to rock. in a crack) These compounds cause the rock to melt - Xenoliths (pieces of rock that at lower temperatures. are embedded in igneous WHY : Rocks close to its melting point rock) and some water (a flux that promotes b. Extrusion - lava and volcanic rock melting) is added to the rock, the melting temperature is reduced (solid line vs. dotted line), and partial melting starts. This creates magma in places where it originally maintained its solid structure. In short, it affects the melting temperature. WHERE : Subduction zones (Convergent plate boundaries) Occurs commonly in subduction zones in the sea (convergent plate boundaries), where the oceanic plates sink into the mantle. The subducted plate releases water (flux) that lowers the melting point of the magma, causing it to require less heat for it to melt. 6 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 3 : STRESS FOLDING When two forces push towards each other from opposite sides, the rock layers TENSIONAL STRESS will bend into folds. Causes rocks to be pulled apart that result TYPES OF FOLDS in lengthening and breaking apart. 1. Anticlines WHERE : Divergent plate boundaries 2. Synclines ANTICLINE Fold that arches upward where the oldest rocks are found at the center of the anticline. Youngest rocks are covered over them at the top of the structure. SYNCLINE COMPRESSIONAL STRESS Fold that bends downward which rocks are curved down to a center. Causes rocks to fold or fracture. Squeeze the rocks together. WHERE : Convergent plate boundaries FAULTING FAULT : a rock under ample stress can SHEAR STRESS crack and fracture. The fracture is called a JOINT because there is a block of rock left Shearing occurs when forces slide past standing on either side of a fracture line. each other in the opposite direction FAULT PLANE : surface of a fracture which results in slippage and friction. between two sections of a rock in a fault WHERE : Transform plate boundaries line. FOOT WALL : block of rock that lies beneath the fault plane. HANGING WALL : block of rock that lies above the fault plane 7 Earth Science 1ST SEMESTER - 2ND QUARTER REVERSE FAULTS Hanging wall moves up LESSON 4 : INTERNAL HEAT Common along convergent plate boundaries. Caused by compressional stress. HEAT Moving against gravity. Himalayas and Rocky Mountains Is needed in order for organisms to survive. Earth’s internal heat is an essential part of how the Earth system works. LAYERS OF THE EARTH CRUST : extremely thin, cold, brittle and broken into pieces called tectonic plates. MANTLE : thickest layer, made mostly of iron, magnesium, and silicon, it is dense, hot, and semisolid NORMAL FAULTS OUTER CORE : made from iron and nickel and in liquid form Hanging wall moves down. INNER CORE : extremely dense which Common along divergent plate boundaries made is made up of solid iron. Caused by tensional stress Moving along gravity. EXAMPLE : East African Rift HOW IS EARTH’S INTERNAL HEAT STRIKE-SLIP FAULTS REDISTRIBUTED? Fault blocks move horizontally in opposite directions. Caused by shear stress CONDUCTION Coa Heat energy is transmitted through EXAMPLE : San Andreas Fault collisions 8 Earth Science 1ST SEMESTER - 2ND QUARTER PRIMORDIAL HEAT OF THE PLANET CONVECTION REMAINS FROM ITS EARLY STAGE Fluid becomes hotter, which causes its The Earth was formed from the process of molecules to move apart, become less accretion dense. Earth's accretion refers to the process by When it becomes less dense, it rises and which the planet formed about 4.5 billion then cools. years ago through the gradual accumulation When it cools, the fluid’s molecules move of dust, gas, and rocky debris in the early together, becoming more dense. solar system. The fluid sinks back closer to the core, Gravity pulled these materials together, repeating the cycle. creating a growing mass that eventually became Earth. Over time, repeated collisions and the heat from radioactive decay shaped it into the planet we know today. HEAT FROM THE RADIOACTIVE DECAY OF ELEMENTS. RADIOACTIVITY : the energy when the unstable atoms decay RADIOACTIVE ISOTOPES 1. Uranium-235 2. Uranium-238 3. Potassium-40 THERMAL RADIATION 4. Thorium-232 Generates from the emission of electromagnetic waves. GRAVITATIONAL PRESSURE These waves carry the energy away from the emitting object. The more a person descends into Earth’s interior, the amount of pressure increases. ENERGY SOURCES ON EARTH DENSE CORE MATERIAL IN THE CENTER OF Sources of energy related to Earth’s internal THE PLANET sources Coming from within external source The materials of the innermost part of the Non-earth generated Earth are very dense. The inner core is composed primarily of iron and nickel which contributes to the density INTERNAL HEAT OF THE EARTH in the core that ranges between Most of Earth’s internal heat is left over 12,600-13,000 kg/m3. from when our planet was formed about 4.5 billion years ago. The internal heat comes from the following sources 9 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 5 : METAMORPHISM 10 Earth Science 1ST SEMESTER - 2ND QUARTER 11 Earth Science 1ST SEMESTER - 2ND QUARTER 12 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 6 : STRATIFICATION 13 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 7 : DIFFERENT METHODS OF DETERMINING THE AGE OFSTRATIFIED ROCKS 14 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 8 : INDEX FOSSILS 15 Earth Science 1ST SEMESTER - 2ND QUARTER 16 Earth Science 1ST SEMESTER - 2ND QUARTER LESSON 9 : LIVING FOSSILS LESSON 10 : GEOLOGIC TIME SCALE 17 Earth Science 1ST SEMESTER - 2ND QUARTER 18 Earth Science 1ST SEMESTER - 2ND QUARTER 19