Planet Earth: 1st Quarter PDF

PLANET EARTH Earth is the only planet in the solar system known to harbour life. Our planet has a molten nickel-iron core which gave rise to an extensive magnetic field, which, along with the atmosphere, shields us from harmful radiation...

PLANET EARTH Earth is the only planet in the solar system known to harbour life. Our planet has a molten nickel-iron core which gave rise to an extensive magnetic field, which, along with the atmosphere, shields us from harmful radiation coming from the Sun. In this lesson, you will understand why this planet is called the “living planet.” HABITABLE ZONE SOLAR SYSTEM TERRESTRIAL PLANET  Made of rocky material  Very few moons  Surfaces are solid  Relatively small  Don’t have rings 1. Mercury Smallest planet 3. Earth Shortest orbit in the solar system Water systems help create only 2. Venus known environment to sustain life. Hottest planet in the solar system Blue planet Atmosphere of carbon dioxide 4. Mars Extensive of lava flows Red planet JOVIAN PLANET  Multiple moons  Support ring systems  No solid surface  Immense in size Gas Giants – predominantly helium and hydrogen. 5. Jupiter Largest planet 6. Saturn Second largest plane Ice Giants – contain rock, ice, and mixture of water, methane, and ammonia. 7. Uranus Rotates on its side 8. Neptune Outer most planet Earth is remarkably special and unique, the only place in the known universe confirmed to host life and is the only one known for sure to have liquid water in the surface. THE REASON WHY THE PLANET EARTH IS UNIQUE ONE: 1. It has liquid water. ▪ Earth is the only planet in the solar system that has a large amount of liquid water. About 70% of the surface of the Earth is covered by liquid or frozen water. Because of this, Earth is sometimes called “blue planet.” 2. Surface or lithosphere which includes the crust and the upper mantle 3. It has atmosphere that shelters it from the worst of the sun’s rays. VENUS, EARTH, & MARS  SIMILARITIES DIFFERENCES (1) They all are terrestrial planets, made of (7) Venus has no water; solid rocks and silicates; (8) Venus and Mars don’t have oxygen; (2) They all have an atmosphere; (9) Earth has life forms. (3) They all almost have the same time to rotate on their axes; (4) Earth and Mars both have water; (5) They all have carbon dioxide; (6) All have landforms. What are the characteristics of planet that makes it habitable? What evidences show that the Earth is in the right position in the solar system? 1. TEMPERATURE Life seems limited to a temperature range of minus 15C to 115C. In this range, liquid water can still exist under certain conditions. Only Earth’s surface is in this temperature range. 2. WATER Water is regularly available. Life can go dormant between wet periods, but, eventually, water needs to be available. Only Earth’s surface has water, though Mars once had surface water and still has water ice in its polar ice caps. Saturn’s moon, Titan, seems to be covered with liquid methane. 3. ATMOSPHERE Earth & Venus are the right size to hold a sufficient-sized atmosphere. Earth’s atmosphere is about 100 miles thick. It keeps the surface warm & protects it from radiation & small- to medium-sized meteorites. Of the solid planets & moons, only Earth, Venus, & Titan have significant atmospheres. Mars’ atmosphere is about 1/100th that of Earth’s, too small for significant insulation or shielding. 4. ENERGY With a steady input of either light or chemical energy, cells can run the chemical reactions necessary for life. The inner planets get too much sunlight for life. The outer planets get too little. 5. NUTRIENTS All solid planets & moons have the same general chemical makeup, so nutrients are present. Those with a water cycle or volcanic activity can transport and replenish the chemicals required by living organisms. Earth has a water cycle, an atmosphere, and volcanoes to circulate nutrients. Venus, Titan, Io, and Mars have nutrients and ways to circulate them to organisms. EARTH AS A SYSTEM SYSTEM – a set of interconnected components that are interacting to form a unified whole. The Earth system is essentially a CLOSED SYSTEM. EARTH’S SUBSYSTEM 1. Geosphere the solid Earth, consisting of the entire planet from the center of the core to the outer crust. It includes the core, mantle, and crust of the Earth. 2. ATMOSPHERE It is the gaseous layer above the Earth’s surface, primarily composed of 78% nitrogen and 21% oxygen. Other gases like argon, carbon dioxide, carbon monoxide, ozone, and other inert gases made the remaining 1%. 3. HYDROSPHERE the water part of the Earth which circulates among oceans, continents, glaciers, and atmosphere. Oceans cover 71% of the Earth and contain 97.5% of its water. 4. BIOSPHERE the zone of Earth where all forms of life exist.  Interaction between two or more spheres: 1. El Niño (Hydrosphere and Atmosphere) 2. Ozone Exchange (Atmosphere and Biosphere) 3. Tectonics (Hydrosphere and Lithosphere) 4. Photosynthesis (Hydrosphere, Atmosphere and Biosphere) Lithosphere - includes the crust and the upper part of the mantle Key Figures: Friedrich Wilhelm von Humboldt: Advocated for a holistic view of the universe. Vladimir Vernadsky: Popularized the term "biosphere." James Lovelock & Lynn Margulis: Developed the Gaia Hypothesis. MINERALS - the building blocks of rocks. Mineralogists use the criteria to determine whether a material is classified as a mineral or not. Characteristics of the Minerals 1. Naturally Occurring – Minerals appear in nature 2. Inorganic – Minerals do not contain high amounts of carbon and hydrogen because they re non-living. 3. Homogenous Solid – Minerals must be solid. It should have definite volume and rigid shape 4. Orderly Crystalline Structure - Minerals have repeating, specific structure at the atomic level. Atoms of minerals are arranged in orderly and repeating pattern 5. Definite Chemical Composition – Specific minerals are made up of specific combinations of elements. Represents by a chemical formula. Physical Properties of Minerals 1. Color: The color of a mineral may change depending on the surface. 2. Streak: The color of the mineral in powdered form. 3. Hardness: The mineral's resistance to scratching. 4. Cleavage: The mineral's ability to break along flat surfaces. 5. Crystalline Structure or Habit: Determined by the arrangement of atoms, molecules, or ions in the crystal and how they are joined, known as the crystal lattice. 6. Luster: The overall sheen of the mineral. 7. Diaphaneity: The ability of a mineral to allow light to pass through it, affected by its chemical makeup. 8. Tenacity: Describes the mineral's reaction to stress, which includes: Brittleness: A mineral that turns into powder. Malleability: A mineral that can be flattened by pounding. Ductility: A mineral that can be stretched into wire. Flexible but Inelastic: Minerals that are bent but remain in the new position. Flexible and Elastic: Minerals that can be bent and return to their original position. 9. Sectility: The ability of minerals to be sliced by a knife. 10. Specific Gravity: The ratio of the density of the mineral to the density of water. Chemical Properties of Minerals  ROCKS A rock is a naturally occurring solid aggregate of one or more minerals. The aggregate minerals forming the rocks are held together by chemical bonds. Grains can be different in color, texture, and sizes. Petrology: The scientific study of rocks. Types of Rocks 1. Igneous Rocks Formation: Formed from the solidification of molten rock material (magma or lava). o One of the three major categories of rocks. o Derived from the Latin word for fire, ignis or ignus. o Commonly found on the surface and beneath the Earth. Specific locations include: ▪ Divergent boundaries ▪ Convergent boundaries ▪ Subduction zones ▪ Hotspots Characteristics Igneous rocks differ in: o Origin o Process of formation o Color o Density o Size of grains and crystals Formation Process Formed through solidification and crystallization of molten rocks (magma and lava). When molten rocks reach the Earth's surface: o They undergo changes in temperature and pressure. o Cool, solidify, and crystallize. Solidification and crystallization also occur with magma beneath the Earth. Types of Igneous Rocks Based on Formation Intrusive Rocks (Plutonic): o Formed from magma. o Located beneath the Earth's surface. o Cools slowly, resulting in large/coarse grains and crystals.  o Examples: Granite, Diorite, Gabbro. Extrusive Rocks (Volcanic): o Formed from lava. o Found on the surface of the Earth. o Cools quickly, resulting in fine/small grains or no grains. o Examples: Basalt, Obsidian, Rhyolite. Intrusive Rocks Extrusive Rocks Other Terminology Plutonic Volcanic Location Beneath Earth Surface of Earth Process of Formation Plutonic Volcanic Origin Formed from magma Formed from lava Color Usually dark Usually light colored Density Usually dense Usually low density (light) Composition Mafic: magnesium and iron Felsic: feldspar (aluminum) Rate of Cooling Cools slowly Cools quickly (with voids/holes) Size of Grains Large/coarse grains Fine/small or no grains (fine/glassy) Size of Crystals Large crystals Small or no crystals Types of Igneous Rocks Based on Composition Ultramafic Igneous Rocks: o Low silica content (< 45% SiO2). o Very low viscosity before formation. o Color: black (peridotite) to olive green (dunite). o High density; rich in pyroxene and olivine. o Examples: Peridotite, Dunite. Mafic Igneous Rocks: o Low silica content (45-52% SiO2). o Low viscosity; black color. o High density; composed of pyroxene and calcium-rich plagioclase feldspar. o Examples: Gabbro, Basalt. Intermediate Igneous Rocks: o High silica content (53-65% SiO2). o Intermediate viscosity; gray color. o Intermediate density; composed of biotite, alkali feldspar, and quartz. o Examples: Diorite, Andesite. Felsic Igneous Rocks: o Very high silica content (> 65% SiO2). o High viscosity; light color. o Very low density; composed of quartz and alkali feldspar. o Examples: Granite, Rhyolite. Types of Igneous Rocks Based on Texture Phaneritic Texture: o Rocks have large minerals (e.g., Granite). Aphanitic Texture: o Mineral grains are too small to see with the unaided eye (e.g., Basalt). Vesicular Texture: o Rocks have many pits from gas escape (e.g., Basalt). Porphyritic Texture: o Rocks have two distinct grain sizes, large and small (e.g., Andesite Porphyry). Glassy Texture: o Rocks do not have obvious minerals (e.g., Obsidian). 2. Sedimentary Rocks Formation: Formed through the accumulation, compaction, and cementation of sediments. Types:  o Clastic/Terrigenous: Formed from accumulation of clasts (e.g., Conglomerate, Breccia, Sandstone, Shale). o Non-clastic / Chemical/Biochemical: Formed when dissolved minerals precipitate from a solution (e.g., Halite). o Organic: Formed from the accumulation of animal debris (e.g., Coal). 3. Metamorphic Rocks Formation: Form from pre-existing rocks (igneous, sedimentary, or metamorphic) due to changes in pressure and temperature. Textures: o Foliated: Appears banded or layered, contains crystals. o Non-foliated: Composed of few minerals. Types of Metamorphism: o Contact Metamorphism: Occurs due to heat from nearby magma. o Regional Metamorphism: Occurs over large regions due to changes in pressure and temperature. Change - It is a Greek word which means “change”. Pressure - It is one of the factors affecting metamorphic rock which creates lineation. Heat - It is the main factor of contact metamorphism. Metamorphism - It is a process of changing rock formation. Metaconglomerate A rock sample which may be distorted or stretched. Anthracite - A rock sample with carbon composition. Geologic Processes on Earth EXOGENIC - Originating ON or ABOVE the surface of the Earth. ENDOGENIC - Originating WITHIN the Earth. Exogenic processes A. Weathering is breaking down or dissolving of rocks and minerals on the surface of the earth. 1. Mechanical weathering or physical weathering is the breakdown of rocks into pieces without any change in its composition. Agents: Ice Wind Water Gravity Plants Animals Humans Factors that illustrate mechanical weathering Pressure caused by a pressure pushing down on the rock and causing it to break. When the rock expands because of overlying materials are removed above the rock. 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. 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 rounded. Organic Activity The roots grow causing penetration into the crack, expand, and in the long run, break the rock. Human Activities Activities such as digging, quarrying, denuding forests and cultivating land contribute to physical weathering. Burrowing Animals Animals like rats, rabbits and squirrels excavate into the ground to create a space for habitation. 2. Chemical weathering is different from mechanical weathering because the rock changes, not just in size of pieces, but in composition. 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 reaction. Hydrolysis Rock-forming minerals like amphibole, pyroxene, and feldspar react with water and form different kinds of clay minerals. 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. B. Erosion and Deposition EROSION The process when rock particles are moved from one place to another. DEPOSITION The process by which sediments are dropped off by agents of erosion. Agents of erosion Erosion: The process of moving rock particles from one place to another. Deposition: The dropping off of sediments by agents of erosion. Agents of Erosion: Water: Erosional Landforms: River Valleys Waterfalls Potholes Terraces Gullies/Rills Meanders Oxbow Lakes Peneplains Depositional Landforms: Alluvial Fans/Cones Natural Levees Deltas Wind: Carries and deposits loose rock and soil particles. Gravity: Drives erosion and deposition through mass wasting. Mass Wasting. is the movement of rock and soil down slope under the influence of gravity. Four Main Types of Mass Wasting 1. Slumping - occurs where cliffs are made up of soil and boulder clay. 2. Rockfalls - involves rock fragments (SCREE) breaking away from the cliff face, often due to freeze-thaw weathering. 3. Landslide - mass movement of rock, soil, and debris down a slope due to gravity. It occurs when the driving force is greater than the resisting force. 4. Mudslide - occur when saturated soil and weak rock flow down a slope. These typically occur where cliffs are made up of boulder clay. ENDOGENIC PROCESSES Sources of Heat/ Heat Transfer Conduction: o Governs thermal conditions in solid portions of the Earth (lithosphere). o Occurs at the Earth's surface. o Defined as the transmission of heat through collisions between neighboring atoms or molecules. o Transfers heat from the Earth's core and radiation from the Sun to the surface. o Involves contact between the warm surface and the atmosphere, which heats the air via convection.  Convection: o Involves heat transfer by the movement of mass, more efficient than pure conduction. o Dominates thermal conditions in fluid zones (e.g., outer core and mantle). o The mantle behaves like a viscous fluid due to high temperatures. o Convection currents cause the slow movement of the mantle, influencing tectonic plate movement. o Hot materials at plate edges cool, become dense, and sink at ocean trenches, leading to volcano formation. Radiation: o The least significant mode of heat transport within the Earth. o Governs heat exchange between the Sun and the Earth, controlling surface temperatures. o Inside the Earth, significant only in the hottest parts of the core and lower mantle. o Warm land and water emit long-wavelength infrared radiation, absorbed by the atmosphere. o Convection in the air spreads thermal energy throughout the atmosphere, continuing even at night. Earth’s Internal Heat Primordial Heat: o Originated during the early formation of the Earth. o Internal heat energy accumulated through dispersion over millions of years. o Major contributor: Accretional Energy – energy deposited during the planet's formation. o The core acts as a storage for primordial heat, resulting from the transformation of kinetic energy from colliding particles into thermal energy. o Heat is continuously lost to the outer silicate layers of the mantle and crust via convection and conduction. o Takes tens of thousands of years for core heat to reach the Earth's surface. o Earth's surface has been composed of cold, rigid rock for approximately 4.5 billion years, while the core remains extremely hot. Radiogenic Heat: o Thermal energy released from spontaneous nuclear disintegration. o Involves the decay of natural radioactive elements within the Earth, such as: o Uranium o Thorium o Potassium o Uranium is significant because its decay produces radiogenic heat. o Estimated heat flow from Earth's interior to the surface is about 47 terawatts (TW). o The flow comes from two main sources in equal amounts: o Radiogenic heat from radioactive decay of isotopes in the mantle and crust. o Primordial heat remaining from Earth's formation. o Radioactive elements are present in significant concentrations throughout the Earth. o Without radioactive decay, there would be fewer volcanic eruptions, earthquakes, and less formation of mountain ranges. MAGMATISM What is Magma? Definition: o Magma is a semi-liquid, hot molten rock located beneath the Earth's surface. o Found specifically in the melted mantle rock and oceanic plates. Formation of Igneous Rocks: o When magma solidifies, it creates igneous rocks that are found on the Earth's surface. Difference Between Magma and Lava: o Both are forms of molten rock. o Magma: o Located in the magma chamber of a volcano. o Lava: o Found on the Earth's surface after a volcanic eruption. Magmatism: o A process that occurs under the Earth's crust involving the formation and movement of magma.  o Formation and movement take place in: o The lower part of the Earth's crust. o The upper portion of the mantle, known as the asthenosphere. How is Magma Formed? Location of Magma: o Present in the lower crust and upper mantle of the Earth. Process of Formation: o Generated through partial melting. o Different minerals in rock melt at varying temperatures and pressures. o Addition of volatile materials (e.g., water and carbon dioxide) influences the melting process. Melting in the mantle requires one of three possible events to occur: 1. Increase in Temperature: o Heat transfer occurs from hotter molten rocks to the Earth's cold crust (conduction). o As magma rises, it can be hot enough to melt surrounding rock. o Melting typically occurs at convergent boundaries where tectonic plates collide. o The temperature of the mantle is around 1200 degrees Celsius. o Minerals like quartz and feldspar begin to partially melt at 650-850 degrees Celsius. 2. Decrease of Pressure: o Mantle rocks remain solid under high pressure. o Convection causes these rocks to rise, reducing pressure and triggering melting (decompression melting). o This process commonly occurs at the Mid-Ocean Ridge. 3. Addition of Volatiles: o The introduction of water or carbon dioxide to hot rocks leads to flux melting. o This lowers the melting points of minerals within the rocks. o If a rock is near its melting point, adding volatiles can initiate partial melting. o This process is prevalent around subduction zones.