Endogenic Processes PDF

ENDOGENIC PROCESS - processes that is Crust broken into many pieces is formed or occurring beneath the called plates. Plates “float” on the surface of the Earth. soft, semi-rigid asthenosphere. Mantle – largest layer of the Earth...

ENDOGENIC PROCESS - processes that is Crust broken into many pieces is formed or occurring beneath the called plates. Plates “float” on the surface of the Earth. soft, semi-rigid asthenosphere. Mantle – largest layer of the Earth - 2900 km thick - Middle mantle is composed of very hot, dense rock that flows like asphalt under a heavy weight. - Asthenosphere is why the crustal plates move. Asthenosphere – semi-rigid part of the middle mantle that flows like asphalt under a heavy weight. The middle mantle “flows” due to convection currents. Convection Currents - very hot material at the deepest part of the mantle rising being less dense, then cooling becoming more dense and sinking again – repeating cycle. Outer Core - molten (liquid) metal Crust - thinnest layer of the Earth that is about 4,700 C (8500 F) - Large amounts of silicon and - Thickness: 2,266 km (1,400) aluminum miles - Composed of plates, these - State of matter: composed of “ride” over molten mantle melted metals nickel and iron - Part of lithosphere (liquid) - 2 types: oceanic, continental - Located about 1,800 miles beneath the crust. Inner Core – solid sphere made mostly of iron and has nickel - Hot as 6,650 C (12,000 F) - Heat in the core generated by the radioactive decay of uranium and other elements - Solid because of the pressure from the outer core, mantle, and crust compressing it. Lithosphere (crust & upper mantle) - - Thickness: 1271 km (800 miles) divided into separate plates which Earth’s Internal Heat Source: moves very slowly in response to the “convecting” part of the mantle. Primordial Heat – accretional energy – energy deposited during the early formation of a planet. Core is a storage of primordial heat that originates from times of accretion when kinetic energy of colliding particles was transformed into thermal energy. This heat is constantly lost to the outer silicate layers of the mantle and crust of the earth through convection and conduction. 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 heat exchange between the Sun and the rigid rock since 4.5 billion years Earth, through radiation, controls the ago, the earth’s surface cools from temperatures at the Earth's surface. the outside but the core is still made Inside the Earth, radiation is of extremely hot material. significant only in the hottest parts Radiogenic Heat – thermal energy of the core and the lower mantle. released as a result of spontaneous Magma – a mixture of molten rock, nuclear disintegration. Involves the minerals, and gases. disintegration of natural radioactive - Originates in the lower part elements inside the earth – like of the Earth’s crust and in Uranium, Thorium and Potassium. the upper portion of the Uranium is a special kind of element mantle known as asthenosphere. because when it decays, heat (radiogenic) is produced. 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. Radioactive elements exist everywhere on the earth in a fairly significant concentration. Without the process of radioactive decay, there would be fewer volcanoes How magmas are formed - at about 30- and earthquakes – and less formation 65km below the Earth’s surface, the of earth’s vast mountain ranges. temperature is high enough to melt Heat Transfer – Conduction: direct; rocks into magma. Temperature rises governs the thermal conditions in about 30 almost entire solid portions of the degree Earth and plays a very important role for in the lithosphere. Heat from the every Earth's core and radiation from the km. 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 - Asthenosphere which is 100- air through convection. 350km deep is hot that most of Convection: fluid or gas of molecules; the rock is melted. Magma involves transfer of heat by the reaches between 600-140C. 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 (molten rocks) exist, and thus governs the heat transport in the fluid outer core and the mantle. In geological time scale, the mantle behaves as a viscous fluid due to the existence of high Gases in Magma – as magma rises at the temperatures. surface of the Earth, pressure is Radiation: electromagnetic radiation. decreased and the gas forms a separate Is the least important mode of heat vapor phase. Similar to carbonated transport in the Earth. The process of drinks.  - When magma emerges on the upper mantle and crust. Where the surface, it is called lava. temperature and pressure conditions Lava spilling over or erupting favor the molten state. Magma collects from craters is usually bubby, in areas called magma chamber. a sign that gases are - The pool of magma in a magma escaping. chamber is layered. The least Viscosity of Magmas - resistance to dense magma rises to the top. flow (an antonym for fluidity) The densest magma sinks at the - Magma with higher silica bottom of the chamber. content has higher viscosity. - During an eruption gases, ash - Magma with low temperature has and light-colored rocks are higher viscosity than those emitted from the lease dense with high temperature. top layer magma chamber. Dark, Magma Escape Routes – 2 major ways: dense volcanic rock from the intrusion or extrusion. lower part of chamber may be released later. - Intruded into low-density area of another geologic form such Ways to Generate Magma as sedimentary rock. When it 1. Decompression Melting – involves cools and hardens; this the upward movement of the Earth’s mostly solid mantle. This hot material rises to an area of lower pressure through the process of convection. 2. Transfer of Heat – happens when hot, liquid rock intrudes into the Earth’s crust. As the liquid rock solidifies, it loses this heat and transfers it to the surrounding crust. This is similar to hot fudge poured over intrusion develops into a cold ice cream. pluton commonly known as an 3. Flux Melting – occurs when water igneous intrusive rock. or carbon dioxide added on rocks - Magma rises towards earth’s these affects the melting point surface where less dense of rock when added with water surrounding rocks are and when beneath the earth it generates a structural zone allows magma. movement. Magma Chamber – magma develops within the Types of Magma 1. Felsic Magma – low in iron but high in potassium and sodium makes granite rocks. 2. Intermediate Magma – normally found in volcano that erupts, after the eruption it releases a lava that has high silica and  very viscous/it commonly produce andesite rock. 3. Mafic Magma – low silica but high in iron and magnesium. Low gas content and low viscosity. Means that mafic magma is the most fluid of all magma types. 4. Ultramafic Magma – hottest and fastest flowing magma. 2. Strain – ability of a rock material to handle stress depends on the elasticity of the rock. a. Elastic Deformation – the rock returns to nearly its original size and shape when stress is removed. b. Brittle Deformation – rocks crack/fracture c. Ductile Deformation – rocks flow 3. Joints – fractures in rocks that show little or no movement at all. 4. Faults – extremely long and deep break or large crack in a rock - A result of continuous pulling and pushing. a. Dip-slip fault(normal fault) – when brittle rocks Rock Deformation – rocks become are stretched-tectonic thicker under compressional stress and tensional forces are thinner under tensional stress. Rock involved and the movement layers tend to bend and go out of of blocks or rock is mainly shape. The high temperature condition in the vertical direction makes a rock softer, less brittle, and (sinking and rising) more ductile. 1. Stress – force that coukd create deformation on rocks in their shape and volume. Pulling, pushing, squeezing. a. Lithostatic Stress – rock beneath the earth’s surface experiences equal pressure exerted on it from all directions because the weight of the overlying b. Strike-slip fault – occurs rock. when brittle rocks are b. Differential stress – sheared (the opposing caused by an additional due tectonic forces are at to unequal stress due to right angles to compression tectonic forces; 3 kinds and tension directions) are tensional stress (stretching), compressional stress (squeezing), shear stress.  Folds – promoted by high temperature and pressure at great depth. a. Monocline – simplest types of folds. Occur when the horizontal layers are bent upward so that two limbs of the fold are still horizontal. c. Reverse (or thrust) fault – b. Syncline – fold occur when brittle rocks structures when are pushed (the tectonic the original rock forces are compressional) layers have been folded downward and two limbs of the fold dip inward toward the hinge of the fold. c. Anticline – originally rock layers have been folded upward and the two limbs of the fold dip away from the hinge of the fold. Synclines and anticlines usually occur together that the limb of a syncline is also the limb of an anticline. The anticline may form mountains, hills or ridges while the syncline may form valleys. Faults and fold are geological structure that result from the response of rocks to tectonic stresses induced by plate movements.