Earth and Life Science W4 Rocks and Minerals

Earth and Life Science W4 Rocks and Minerals

1. Overview What is the external processes and events that occur on and above the earth's surface?

2. E X OGENIC PROCESS

3. Chapter 5: Earth Materials and Processes ENDOGENIC PROCESS

4. Processes that is formed or occurring beneath the surface of the Earth . ENDOGENIC PROCESS

5. What makes the internal of the Earth hot? The Earth’s interior heat comes from several sources which includes heat produced when the planets formed and accreted, frictional heating and decay of radioactive elements.

6. SOURCES OF THE EARTH’S INTERNAL HEAT 1. Heat from the formation and accretion of planet This source of heat is a leftover during the formation of planet around 4.6 billion years ago. It was thought that planetoids had accreted from dust, hurtled around the sun, and crashed into each other to formed planets. Moreover, the collisions build up a surprising amount of heat-over 10,000 Kelvin (9,726.85 °C).

7. The history of Earth’s accretion did not stop there. Three other major accretion events happened. First , less than 100 million years after the Earth’s initial formation, Earth, and Theia (a planet, with an original mass of about 15–45 percent of Earth’s original mass) merged, increasing Earth’s mass, thus, producing the Moon. This merging event was considered the most significant after Earth’s initial formation and had vastly added to Earth’s heat-bank. Secondly , after the Moon-forming event, Earth received a “late veneer”-a bombardment by large asteroids and comets. Lastly , about 3.9 billion years ago, Earth received the late heavy bombardment of large asteroids and comets.

8. SOURCES OF THE EARTH’S INTERNAL HEAT 2. Frictional heating Frictional heating, caused by denser core material sunk to the center of the planet. As it sunk, the friction may have generated heating of as much as 2000 Kelvin or 1726.85°C, which is smaller than the other sources of heat but still extremely significant.

9. SOURCES OF THE EARTH’S INTERNAL HEAT 3. Heat from the decay of radioactive elements T he heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms.

10. a mixture of molten rock, minerals and gases. This mixture is usually made up of a hot liquid base called the melt, minerals crystallized by the melt , solid rocks incorporated into the melt from the surrounding confines and dissolved gases . MAGMA

11. originates in the lower part of the Earth’s crust and in the upper portion of the mantle known as asthenosphere . MAGMA

12. At about 30 to 65 km below the earth’s surface, the temperature is high enough to melt rocks into magma. The reason why it is difficult to drill holes deep into the crust is that the temperature rises about 30 degree for every kilometer . The asthenosphere which is between 100 to 350km deep is so hot that most of the rock is melted . The melt flows very slowly because it is under intense pressure. Magma reaches temperatures between 600 degree 140 degree Celsius. How Are Magmas Formed ?

13. Deep in the Earth, nearly all magmas contain gas dissolved in the liquid, As magma rises at the surface of the Earth, pressure is decreased and the gas forms a separate vapor phase. This is somewhat similar to carbonated beverages which are bottled at high pressure. When magma emerges on the surface of the Earth, it is called lava. Lava spilling over or erupting from craters is usually bubbly, a sign that gases are escaping. Gases in Magma

14. Viscosity is the resistance to flow (an antonym for fluidity). Magma with higher silica content has higher viscosity. Viscosity increases with increasing silica concentration in the magma. Magma with low temperature has higher viscosity than those with high temperature. Viscosity decreases with increasing temperature of the magma. Viscosity of Magmas

15. Magma leaves the confines of the asthenosphere and crust in two major ways; an intrusion or extrusion. Magma can intruded into low-density area of another geologic form such as a sedimentary rock. When it cools and hardens, this intrusion develops into a pluto nic commonly know n as an igneous intrusive rock. Magma rises towards the Earth`s surface where are less dense surrounding rocks and when a structural zone allows movement. Magma Escape Routes

16. Magma develops within the upper mantle and crust where the crust where the temperature and pressure conditions favor the molten state. Magma collects in areas called magma chamber. There pool of magma in a magma chamber is layered. The least dense magma rises to the top. The densest magma sinks at the bottom of the chamber. During an eruption, gases, ash and light-colored rocks are emitted from the least dense top layer magma chamber. Dark, dense volcanic rock from the lower part of chamber may be released later. Magma Chamber

17. Decompression Melting Increase in temperature Flux Melting Ways to Generate Magma

18. 1) Decompression Melting Ways to Generate Magma involves the upward movement of the Earth’s mostly solid mantle t his hot material rises to an area of lower pressure through the process of convection.

19. 2) Increase in Temperature Ways to Generate Magma Though it is considered as the least among the three process, magma formation is also possible with this process. Recall the previous lesson on Earths internal heat, as the depth ???? towards the core, the temperatur e also ?????. With the increasing temperature, the solid rock masses begin to vibrate then the bonding between them breaks and finally convert into magma.

20. 3 ) Flux Melting Ways to Generate Magma It occurs when water or carbon dioxide added on rocks these affects the melting point of rock when added with water beneath the earth it generates magma.

21. Types of Magma Mafic / Basaltic Magma Felsic / Rhyolitic Magma Intermediate / Andesitic Magm a

22. This type of magma has viscosity level there has low in iron but high in potassium and sodium this form makes granite rocks. Felsic Magma

23. Mafic magma has relatively low silica content but high in iron and magnesium. This magma has a low gas content and low viscosity. Mafic magma has high average temperature which contributes to its low velocity. Low velocity means that mafic magma is the most fluid of all magma types. Mafic Magma

24. This normally found in volcano that erupts, after the eruption it releases a lava that has high silica and very viscous . it commonly produced Andesite Rock. Intermediate Magma

25. Mafic Magma basalt

26. Today our planet is to cool, for ultramafic magma to form. This is a probably a good thing, since ultramafic magma would be the hottest and fastest flowing magma. Ultramafic Magma

27. Felsic Intermediate Mafic Rhyolite Ultramafic Granite Volcanic Andesite Diorite Plutonic Coarse Texture Fine 70% SiO Composition 40% SiO 2 2 Basalt Gabbro Peridotite