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Earth crust and its composition
- 1. EARTH CRUST AND ITS COMPOSITION DR. S.H.SINGH
- 2. Did you know………..????? Earth is over 4.5 billion years old The continents move and have joined together to create supercontinen Geology is the study of the earth (geo means earth, and ology means study of).
- 3. the materials that make up the earth features and structures found on Earth processes that act upon them
- 4. Typically, geology is divided into two categories: Physical geology: deals with the study of the physical features of the earth and the processes acting on them. This includes volcanoes, earthquakes, rocks, mountains and the oceans; just about any feature of the earth
- 5. Historical geology: is the study of the history of the earth. Historical geologists focus on what's happened to Earth since its formation. They also study the changes in life throughout time. In historical geology, you essentially get to travel back in time to the formation of the earth and move forward through time, witnessing the changes in Earth itself and the life on it
- 6. H I S T O R Y Ancient Greece in the 4th century . Aristotle
- 7. 17th century: fossils played a key role in the debate about the age of Earth 18th century: two main theories -all rocks were deposited by the oceans during flooding events. - some rocks were formed through heat or fire 19th century: James Hutton, proved that some rocks are formed by volcanic (heat & fire) processes and others are formed by sedimentation.Uniformitarianism which simply states says 'the present is the key to the past.' James Hutton is known as the Father of Modern Geology Early 1900s: Alfred Wegener proposed a theory called Continental Drift. Wegener suggested that the continents moved around on the surface of the earth and came together to form a supercontinent known as Pangaea. James Hutton Alfred Wegener
- 8. INTRODUCTION The Earth is divided into 4 “Sub-systems” or “Spheres” namely: ATMOS(Gaseous)-SPHERE. HYDRO(Water)- SPHERE LITHOS(Rocky)-SPHERE (aka geosphere) BIOS(Life)-SPHERE They are interdependent and function as a whole.
- 9. THE ATMOSPHERE Blanket of air which surround the Earthreaches over 560 kilometers (348 miles) up from the surface of the Earth.
- 10. FUN FACT…… Extreme athlete Felix Baumgartner made history with his amazing space jump on Oct. 14. After floating to the edge of Earth's atmosphere in a balloon-lifted capsule, Baumgartner performed a record-breaking free- fall jump, covering 23 miles at 834 mph before opening his parachute and dropping safely to terra firma
- 11. The Biosphere “life zone” of the Earth, and includes all living organisms , and all organic matter that has not yet decomposed •The biosphere is structured into a hierarchy known as the food chain (all life is dependent on the first tier – mainly the primary producers that are capable of photosynthesis). • Energy and mass is transferred from one level of the food chain to the next.
- 12. contains all the water found on our planet. Hydrosphere on the surface ocean as well as water from lakes and rivers, streams, and creeks under the surface water trapped in the soil, groundwater, and water tables in our atmosphere water vapor
- 14. Lithosphere The lithosphere (from the Greek [lithos] for "rocky" + [sphaira] for "sphere") is the rigid outermost shell of a rocky planet. It consists of three main layers: crust, mantle and core.
- 16. The Earth's Crust: the topmost layer, made mostly out of solid silicate rocks like basalt and granite. the crust can be a whopping 70 kilometers thick The uppermost layer is known as the SIAL. It is composed mainly of silicon and aluminum The bottom layer of the crust is called SIMA. It is made mostly of silicon and magnesium. Continental crust: about 32 kilometers thick, made mainly of granite rocks. Oceanic Crust: seven kilometers thick and made mainly of basalt.
- 18. The region between the crust and the mantle is called MOHOROVICIC DISCONTINUITY OR MOHO
- 20. moves and flows in convection currents much more easily than the lower part
- 21. The Core Outer core: about 2,270 km thick. Composed mainly of nickel and iron melted by intense heat. The temperature ranges from 4,000 C to 5,000 C Inner Core: composed mainly of solid iron and nickel. The temperature is around 5,000 C to 6,000 C. The pressure is exceedingly high
Editor's Notes
- Geology has been of interest to humans as far back as ancient Greece in the 4th century. Aristotle was one of the first people to make observations about the earth. This was also the first time that scientists and philosophers noted a difference between rocks and minerals. The Romans became very adept at mining certain rock for use in building their empire, especially marble.
- Underneath the crust is the mantle, the largest layer, composed of rocky oxides and silicates under high pressure. We once thought the mantle contained liquid magma, but we now know that is not the case; magma is formed only in certain locations, due to the high pressures and temperatures. The mantle is huge, going down to a depth of 2,500 km
- The mantle is sometimes split into the upper mantle and lower mantle because the upper part of the mantle moves and flows in convection currents much more easily than the lower part. Even solid rock can move and flow at these high pressures and temperatures, though it moves very slowly.
- Below the mantle is the core, which is the very center of the Earth, made mostly of metals like iron. The outer core is a liquid that flows in circles. The inner core, on the other hand, is the solid part that is believed to contain at least 90% iron. The outer core goes from a depth of 2,550 km down to 4,750 km, and the inner core continues to the center of the Earth at a total depth of 6,470 km.