Science Layers of The Earth PDF

Layers of the Earth Magma It is an extremely hot liquid and semi-liquid rock located underneath the Earth’s surface. Lava Lava is a molten or partially molten rock (magma) ejected by volcanoes in the form of a liquid outside the Earth’s s...

Layers of the Earth Magma It is an extremely hot liquid and semi-liquid rock located underneath the Earth’s surface. Lava Lava is a molten or partially molten rock (magma) ejected by volcanoes in the form of a liquid outside the Earth’s surface. The Theory Through the Centuries 1. Edmond Halley Upper Mantle Halley's model of the Earth's interior This layer is hard and brittle and is takes the form of a series of hollow where tectonic plates exist. It is also spheres around a central core. His fairly plastic. argument was that the exterior of the Earth has its own magnetic north and Mantle south pole, but that there must be four It is molten; flowing freely. poles in total. It has convections similar to boiling water. 2. John Cleves Symmes Jr. The layer between the crust and the In its original form, Symmes’s Hollow core. Earth theory described the world as consisting of five (5) concentric spheres, Crust with our outer Earth and its atmosphere The thin, hard, outermost layer of the as the largest. Earth. He argued that due to the centrifugal force of Earth's rotation, the Earth Core would be flattened at the poles, leading The extremely hot, dense center of the to a vast passage into the inner Earth. Earth. It is composed mainly of nickel-iron True North alloy. True north is the direction that points directly towards the geographic North Outer Core Pole. This is a fixed point on the Earth's The liquid iron layer that covers the globe. inner core. Continental Crust Inner Core Thick and divided into tectonic plates. The solid iron center of the Earth. Consists primarily of granite and gneiss. Oceanic Crust Continental Drift Thinner; it is when a new crust is Geologists formed. People who study Earth’s nature, behavior, and history. The Asthenosphere The supplier of new material for the Abraham Ortelius lithosphere. The Dutch geographer and cartographer Consists of the upper mantle. first noted this observation in the late 1960s. The Lithosphere Consists of the crust and the uppermost Alfred Lothar Wegener (W pronounced as V) portion of the mantle. The German meteorologist and It is divided into several segments called geophysicist proposed the idea of the tectonic plates. drifting continents in his book “The Origin of the Continents and Oceans” in The Mesosphere 1912. Comprised of the lower mantle. It is between the asthenosphere and the Pangaea outer core. A single huge land mass or The rocks in this layer also behave supercontinent once existed in the plastically but flow much more slowly distant past. and rigidly than asthenospheric rocks. A Greek word that means “all lands”. The MOHO Mesosaurus Characterized by a drastic increase in An extinct group of aquatic reptiles that seismic rate. have lived thousands of million years Discovered by Andrija Mohorivicic. ago. Compositional Layers Lystrosaurus & Cynognathus Composed of the crust, mantle, and Two (2) extinct groups of ancient core. mammal-like reptiles have been found only in several continents. Mechanical Layers Consist of the lithosphere, Glossopteris asthenosphere, mesosphere, outer An extinct group of seed ferns, have core, and inner core. been found in Australia, India, South America, and South Africa. They had large seeds; thus, it would have been impossible for the seeds to be carried away by the wind at considerable distances across Earth.  Evidence for Continental Drift Sonar Technology Fossil Records A modern technique that uses sound Fossils of similar types of plants and waves to detect and track underwater animals in rocks of similar age. These vessels, fish, and other objects under rocks were on the shores of different the ocean. continents. This suggests that the continents were once joined. Jigsaw Puzzle For example, fossils of Mesosaurus, a Alfred Wegener published a theory to freshwater reptile, have been found explain why the Earth looked like a huge both in Brazil and western Africa. jigsaw. He believed the continents were Glacial Striations (i.e., scratches on once joined, forming a supercontinent bedrocks that were caused by glaciers he called Pangaea. Over 180 million that were moving downslope). years ago, this supercontinent began to “break up” due to continental drift. Geologic Features The fit of the continents; the Mid-Ocean Ridges distribution of ancient fossils, rocks, and These are chains of mountain ranges mountain ranges; and the locations of that are about 3 km above the ocean ancient climatic zones. floor. These structures are interconnected Seafloor Spreading and form the oceanic ridge system, Observing and measuring magnetic which traverses every major ocean anomalies that occur around mid-ocean around the globe. ridges. The magnetic field of the Earth originates from electrical and magnetic Evidence for Seafloor Spreading energy that is generated by the Harry Hess convective energy produced by molten Hess proposed the radical idea that the iron in the core of the Earth. ocean floor move like a conveyor belt, which in turn moves the continents. Rock Magnetism on the Ocean Floor He postulated that a new oceanic Earth also has magnetic north and lithosphere is being generated at south poles. mid-ocean ridges through the process called seafloor spreading. Geomagnetic Reversal This means that Earth’s magnetic north Evidence from Molten Material pole switches positions with its Alvin magnetic south pole. Scientists used a small submarine called The present-day orientation of the Alvin to explore the ocean floor. Earth’s magnetic field is called normal Alvin’s crew found rocks shaped like polarity, whereas its opposite is called pillows or toothpaste squeezed from a reverse polarity. tube.  These rocks showed that molten Microplates material had erupted many different Mostly located within major plates and times from cracks along the mid-ocean measure less than 1 million km². ridge. Ex. Madagascar Plate, Victoria Plate, Shetland Plate, Capricorn Plate, and Evidence from Magnetic Stripes Panama Plate. The Earth is like a giant magnet with a north and south pole. Plate Boundaries The Earth’s magnetic poles reversed Active regions on Earth where tectonic themselves 780,000 years ago. plates interact. All volcanoes are mountains, but not all mountains are volcanoes. Types of Plate Boundaries 1. Divergent Boundary Subduction Zone Regions on Earth where two (2) tectonic Locations on Earth where the oceanic plates are moving away from each material of one tectonic plate dives other. below the material (oceanic or Ex. The Mid-Atlantic Ridge. continental) of another tectonic plate New oceanic lithosphere is being into the mantle. constructed at divergent boundaries; they are also called constructive plate margins. 2. Convergent Boundary Regions on Earth where two (2) tectonic plates are moving toward each other. Plate Tectonic Theory Ex. Caribbean Islands, Himalayan This suggests that these plates are Mountains, Andes Mountains, Cascade constantly moving relative to one Mountains, Appalachian Mountains, another in the processes of plate Aleutian Islands. construction and destruction. a. Oceanic - Continental Major plates are estimated to be more Occur when a tectonic plate primarily than 20 million square kilometers (km²). composed of oceanic lithosphere Minor plates measure between 1 and collides with a plate with continental 20 million km². lithosphere. b. Oceanic - Oceanic  A collision between two (2) plates Destructive Plate Margins or Subduction Zones composed of oceanic lithosphere. The lithosphere is being destroyed in c. Continental - Continental these regions. Occur when two (2) continental plates move towards each other. Island Arcs Magma rises toward the surface of the continental plate, forming curve chains of volcanoes. Activities Along Plate Boundaries Earthquakes These are violent shakings of the Earth’s surface that are caused by the sudden release of stored energy in rocks. Focus 3. Transform Boundary The point from which an earthquake Regions on Earth where two (2) plates originates, whereas epicenter is the are sliding alongside each other. point on Earth’s surface directly above These regions are also called the focus. conservative plate margins because the lithosphere is neither created nor Volcanoes destroyed. These are vents (or openings) in the The fracture where the plates meet is crust through which magma escapes to called transform fault. reach Earth’s surface. Ex. The San Andreas Fault and Queen Charlotte Fault. Pacific Ring of Fire A path along the Pacific Ocean that contains about 75% of the Earth’s volcanoes and where approximately 90% of the Earth’s earthquakes occur. This outlines a series of overlapping boundaries (mostly convergent) between several tectonic plates such as Constructive Plate Margins the Eurasian Plate, Pacific Plates, Where a new oceanic lithosphere is Indo-Australian Plate, North American being constructed at divergent Plate, Juan de Fuca Plate, Cocos Plate, boundaries, and it takes 2-3 years. and Philippine Plate.  Ridge Push Gravity then causes the elevated lithosphere to apply a downslope force that pushes the two (2) plates away from the ridge. The process also pushes away the older part of the lithosphere that lies farther from the ridge. Evidence for Plate Tectonics Tsunami Hot Spots A series of large ocean waves that forms An area within the mantle where rocks when a sudden vertical crustal melt because of the intense heat that is movement in the ocean floor displaces coming from an underlying mantle a huge volume of overlying water. plume. Tsunami waves travel in all directions Mantle Plume is a cylindrical column of away from the earthquake zone. magma that originates deep within the mantle. Driving Mechanisms of Plate Motion Geophysical evidence and laboratory Global Positioning System (GPS) experiments led geologists to postulate A radio navigation system that uses three (3) driving mechanisms of plate satellite signals to allow users to track motion: mantle convection, slab pull, their exact location anywhere on Earth. and ridge push. Trilateration is a method of locating the absolute position of a specific point by Mantle Convection measuring distances using geometric Mantle convection is driven by heat, spheres. whereas slab pull and ridge push are both driven by gravity. Convection is a process of heat transfer by which dense materials sink and less Climate Change & Global Warming dense materials rise. Climate Change The change in Earth’s climate system Slab Pull that results in new, long-term weather As the slab or leading edge of the plates patterns. sink, its weight pulls the rest of the plate behind it. Global Warming Recent studies suggest that slab pull is A significant aspect of climate change as the main driving mechanism of plate it is the long-term increase in the motion because plates that are at the average temperatures of Earth’s climate advanced stage of subduction move system. fastest. Earth’s Atmosphere ➔ Regional Climate Change: Leads to A mixture of different gasses, primarily droughts, floods, or other extreme of nitrogen (78%) and oxygen (21%). weather events. The remaining 1% are called trace gases ➔ Ozone Depression: Increase chlorine’s because they exist in significantly low effectiveness at destroying ozones. concentrations in the atmosphere. Examples of trace gases include carbon Temporary Solution dioxide, methane, nitrous oxide, and The cooling effect of sulfate aerosols is a water vapor. temporary solution. Ex. Mt. Pinatubo erupted in 1991 Influence of Aerosols on Climate ➔ For 2 years, this decreased the global Aerosols surface temperature by about 0.6°C. Fine liquid and solid particles that are Mt. Pinatubo erupted again in 1994 suspended in the air. ➔ The global surface temperatures Ex. Dust, volcanic ash, black carbon, remained at higher levels. smoke, salt particles, and sulfuric acid. Major Source: Ocean Common Factor: Carbon Dioxide Other Natural Sources: Dust storms and A potent greenhouse gas, meaning it volcanic eruptions traps heat in the Earth’s atmosphere. Aerosols, on the other hand, can only How does it affect the climate? remain in the atmosphere for a short Reflect solar radiation back to space. time (up to two (2) years). Decreasing Earth’s surface temperatures. Examples of Aerosol Sulfate Aerosols Is aerosol good for the Earth? Cooling For instance, aerosols can scatter Reflect sunlight back into space, causing incoming sunlight and reduce the a cooling effect. amount of radiation reaching the It can lead to cooler temperatures. Earth's surface, which in turn can cool down the planet. But, on the other side Black Carbon Volcanic Ash of the argument, black carbon or brown Warming Cooling carbon/organic matter can absorb and Ex: Soot re-emit radiant energy, which can contribute to global warming. Dust Sea Salt Warming Cooling Unintended Consequences Introducing large amounts of aerosols Soot into the atmosphere can have Soot getting into ice can accelerate its unintended consequences, such as: melting. ➔ Acid Rain: Damages forests and aquatic ecosystems Greenhouse Gases results in increased precipitation rate Greenhouse gasses (also known as and coastal flooding. GHGs) are gasses in the earth's Increase the possibility of drought, atmosphere that trap heat that cause particularly during the dry season. climate change. Warmer temperatures can also increase outbreaks of food-borne diseases due Greenhouse Effect to the increased rate of spoilage of food The warming of the atmosphere by and growth of harmful bacteria in food. trapping heat being radiated to space. Warm Ocean Water Human Impact on Global Climate Supplies more energy to tropical Earth has gone through several changes, storms, creating stronger and more and many of these are regarded by destructive weather disturbances that scientists as human-caused or can cause great damage to properties. anthropogenic changes. Heavy Rainfall The burning of fossil fuels, such as coal, Can wash out pathogens natural gas, and petroleum, is the (disease-causing organisms) from primary cause of increased greenhouse contaminated areas into drinking water gas concentration in the atmosphere. sources. Consequences of Global Warming Some consequences are glacier and sea ice melting, sea level rise, extreme precipitation rates and weather patterns, widespread diseases, and ecosystem alteration. It also causes the thermal expansion of ocean water. Because warm water has a greater volume than cold water, the volume of ocean water increases. Acid Rain Occurs when aerosols such as sulfate and nitrate react with water, oxygen, and other chemicals, and form acidic compounds. It has harmful effects on living things and infrastructures. Warmer Temperatures Lead to high evaporation rates of surface water which consequently