Earth Materials and Processes: Endogenic Processes PDF

E A R T H M AT E R I A L S A N D P RO C E S S E S : E N D O G E N IC P RO C E S S E S P R E PA R E D B Y: M S. M A. RU S Z E T H S. B E L A N D R E S, L P T, M E D – N AT U R A L S C I E N C E S REVIEW What is an...

E A R T H M AT E R I A L S A N D P RO C E S S E S : E N D O G E N IC P RO C E S S E S P R E PA R E D B Y: M S. M A. RU S Z E T H S. B E L A N D R E S, L P T, M E D – N AT U R A L S C I E N C E S REVIEW What is an exogenic process? Exogenic processes include geological phenomena and processes that originate externally to the Earth's surface. They are genetically related to the atmosphere, hydrosphere and biosphere, and therefore to processes of weathering, erosion, deposition, and mass wasting.  INTRODUCTION The Earth's internal heat source provides the energy for our dynamic planet, supplying it with the driving force for plate- tectonic motion, and for on-going catastrophic events such as earthquakes and volcanic eruptions. This Photo by Unknown Author is licensed under CC BY-NC ENDOGENIC P ROCE S S are geological processes that occurs beneath the surface of the Earth. Forces that cause the Earth surface to move is Endogenic forces. ENDOGENIC P ROCE S S There are two categories of heat the primordial heat, generated during earth’s formation and radioactive heat generated by long- term radioactive.  This Earth system model is one way to represent the essential processes that are related to the Earth’s internal heat, including plate tectonics and the rock cycle.  How human activities are influenced by Earth’s internal heat The use of Earth’s internal heat as a renewable energy source can decrease the burning of fossil fuels and the impact of humans on the Earth system. Heat energy plays a vital role in our planet. It is one of the extreme factors in what makes the world livable. If you think of a volcano, you know Earth must be hot inside. The heat inside of our planet moves continents, build mountains and causes earthquakes, but where T H E E A R T H ’ S I N T E R N A L H E AT does all this heat inside the earth come from? W H AT I S E A R T H ' S I N T E R N A L H E AT ? Most of Earth’s internal heat is left over from when our planet formed, about 4.5 billion years ago. Earth and the other planets in the solar system first began to take shape as countless smaller bodies collided and clumped together. The energy of those violent collisions transformed into heat energy. As the early Earth grew bigger, gravity began pulling matter toward the center. The intense compression of material deep inside the Earth increased internal heat even further. Once temperatures were high enough, the element iron began to melt and sink toward the center, as less dense material rose towards the surface. The friction of the iron moving down through the other material generated even more heat. As denser material sank, layers formed inside the Earth: A core primarily made of iron, the less dense mantle, and even less dense crust. W H AT I S E A R T H ' S I N T E R N A L H E AT ? Since its formation, the Earth has been losing heat to space. Certain elements, known as radioactive elements such as potassium, uranium, and thorium, break down through a process known as radioactive decay, and release energy. This radioactive decay in Earth’s crust and mantle continuously adds heat and slows the cooling of the Earth. After 4.5 billion years, the inside of the Earth is still very hot (in the core, approximately 3,800°C – 6,000°C), and we experience phenomena generated by this heat, including earthquakes, volcanoes, and mountain building. SOURCE OF H E AT: PRIMORDIAL HEAT During the early formation of the Earth, the internal heat energy that gradually gathered by means of dispersion in the planet during its few million years of evolution is called Primordial heat. The major contribution of this internal heat is the accretional energy – the energy deposited during the early formation of a planet. SOURCE OF H E AT: PRIMORDIAL HEAT In addition, the heat of the core takes tens of thousands of years to reach the surface of the earth. Today, the surface of the earth is made of a cold rigid rock since 4.5 billion years ago, the earth’s surface cools from the outside but the core is still made of extremely hot material. S O U RC E O F H E AT: RADIOGENIC HEAT The thermal energy released because of spontaneous nuclear disintegration is called Radiogenic Heat. It involves the disintegration of natural radioactive elements inside the earth – like Uranium, Thorium and Potassium. Estimated at 47 terawatts (TW), the flow of heat from Earth's interior to the surface and it comes from two main sources in equal amounts: the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of the Earth. S O U RC E O F H E AT: RADIOGENIC HEAT Radioactive elements exist everywhere on the earth in a significant concentration. Without the process of radioactive decay, there would be fewer volcanoes and earthquakes – and less formation of earth’s vast mountain ranges. 1. Conduction governs the thermal conditions in almost entire solid portions of the Earth and plays a very important role in the lithosphere. Its processes happen in the earth’s surface. Technically, it can be defined as the process by which heat energy is transmitted through collisions between neighboring atoms or molecules. Heat from the Earth's core and radiation from the Sun is transferred to the surface of the Earth by conduction. Contact of the atmosphere with these warm surfaces transfers thermal energy, which then heats up the rest of the air through convection. 2. CONVECTION Convection involves transfer of heat by the movement of mass, which is a more efficient means of heat transport in the Earth compared to pure conduction. Convection dominates the thermal conditions in the zones where large quantities of fluids In convection current, the mantle of the earth moves slowly because of transfer (molten rocks) exist, and thus of heat from the interior of the earth up to the surface. This result to the governs the heat transport in movement of tectonic plates. Hot materials are added at the edges of a plate the fluid outer core and the and then it cools. At those edges, it becomes dense by its exposure from the mantle. heat and sinks into the earth at an ocean trench. This start the formation of volcanoes.  The process of heat exchange between the Sun and the Earth, through radiation, controls the temperatures at the Earth's surface. Inside the Earth, radiation is significant only in the hottest parts of the core and the lower mantle. When the land and water become warm in summer, they emit long – wavelength infrared radiation that is readily absorbed by the atmosphere. This continues during nighttime too. Convection in the air then spreads out the thermal energy throughout the atmosphere. R A D I AT I O N W H AT ’ S I N S I D E T H E M A N T L E ?  It is nearly as hot as the surface of the sun – about 6000˚C. Convection current is relevant to the movement of tectonic plate because the heat builds up pressure underneath the crust (tectonic plates). As they become unstable, they push against each other (subduction) and rise upwards, or one goes under the other.  The thermal energy of the core is transferred to the surface of the earth and the lower levels of ocean by conduction.  END OF P R E S E N TAT I O N