Earth's lithosphere


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Earth's lithosphere

  1. 1. EARTH’S LITHOSPHERE By: Dr. Tess Consulta Subscribe to her Science Nook Channel in Youtube https://
  2. 2. TYPES OF CRUSTS • Oceanic crust is thin and composed of basalt • The continental crust is composed mainly of lighter granite • Continental crust is thinnest in areas like the Rift Valleys of East Africa and in an area known as the Basin and Range Province in the western United States.
  5. 5. CATASTROPHISM • landforms that occur on the Earth were the result of catastrophic events (like creation and the flood) that occurred very rapidly.
  6. 6. UNIFORMITARIANISM • processes that are taking place at the present time had operated throughout the history of the planet. • "the present is the key to the past".
  8. 8. Type of rocks
  9. 9. PROCESSES INVOLVED IN ROCK CYCLE Weathering breakdown and alteration of rocks and minerals at or near the Earth's surface into products that are more in equilibrium with the conditions found in this environment.
  10. 10. Chemical weathering Hydrolysis • occurs when the two surfaces of water and compound meet. • involves the reaction between mineral ions and the ions of water (OH- and H+) • results in the decomposition of the rock surface
  11. 11. Oxidation • reaction that occurs between compounds and oxygen. • Makes the rocks brittle
  12. 12. Hydration • allows for the acceleration of other decomposition reactions by expanding the crystal lattice offering more surface area for reaction.
  13. 13. Carbonation • active when the reaction environment is abundant with carbon dioxide. • decomposition of mineral surfaces because of its acidic nature.
  14. 14. Dissolution • water + carbon dioxide + calcite dissolve into calcium ion and bicarbonate ion • cause sinkholes and karst features as well as dissolution of statutes and grave stones.
  15. 15. Abrasion • physical grinding of rock fragments. • pits that have been eroded into the rock by sandblasting. PHYSICAL WEATHERING
  16. 16. Crystallization • rock is repeatedly wetted and dried as salt crystals dissolve from the rock then grow when it is dried - mechanical action for rupture. • two types of crystal growth that occur; they are ice and salt.
  17. 17. Frost Wedging • water expands when it freezes. the individual layers within the sedimentary rock breaking apart through repeated cycles of freeze- thaw.
  18. 18. Contraction • heating causes rock to expand, cooling results in contraction; • different minerals expand and contract at different rates. • typically happen in climates that undergo extreme diurnal temperature changes.
  19. 19. Differential weathering • During the process of weathering, hard or resistant material is left behind while softer material is scoured out by the action of wind and water.
  20. 20. Mechanical Exfoliation • rock breaks apart in layers that are parallel to the earth's surface; • as rock is uncovered, it expands (due to the lower confining pressure) resulting in exfoliation.
  21. 21. BIOLOGICAL WEATHERING • Burrowing animals • Increase of carbon through cellular respiration • Chelation – production of chelates (decomposes minerals and remove metallic cations
  22. 22. DIASTROPHISM • deformation of the Earth's crust. • most obvious evidence of diastrophic movement can be seen in sedimentary rock where bent, broken or non- horizontal strata provide visual proof of movement.
  23. 23. TWO TYPES OF MOVEMENTS Folding • occurs when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of plastic (i.e. permanent) deformation
  24. 24. Faults • planar rock fractures which show evidence of relative movement. • Earthquakes are caused by energy release during rapid slippage along faults.
  26. 26. ISOSTACY • The addition of glacial ice on the Earth's surface causes the crust to deform and sink (a). When the ice melts, isostatic rebound occurs and the crust rises to its former position before glaciation (b and c). A similar process occurs with mountain building and mountain erosion
  27. 27. PLATE MOVEMENTS (CONTINENTAL DRIFT) • The plates move in three different ways. They either slide past one another, come together, or pull apart from each other.
  28. 28. • Convection currents in Earth's mantle and their role in oceanic crust formation and destruction
  29. 29. Volcanoes and Earthquakes Adventure
  30. 30. Earthquakes and Volcanoes play a fascinating role in creating and changing the landscapes of our earth.
  31. 31. Introduction An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain that has accumulated over a long time.
  32. 32. Earthquake The trembling or shaking movement of the earth's surface may be minor tremors or usually begin with slight tremors but rapidly take the form of one or more violent shocks, and end in vibrations of gradually diminishing force called aftershocks.
  33. 33. Earthquake The subterranean point of origin of an earthquake is called its focus; the point on the surface directly above the focus is the epicenter.
  34. 34. Shifting and Sliding Along the boundary separating any two plates, the relative motion between the plates can be classified into one of 3 categories: DIVERGENT CONVERGENT TRANSFORMATIONAL
  35. 35. • DIVERGENT Divergent Motion: Movin' Apart This is the most common kind of motion along the mid-ocean ridges. This is a system of undersea mountain ranges that extends beneath the world's oceans and connects together like the seams on a baseball.
  36. 36. Convergent Motion: Comin' Together This is the most common kind of motion at subduction zones. This motion happens where dense oceanic plates colide and slide beneath continental plates.
  37. 37. Transformational Motion: This is the motion of the earthquake as illustrated above… A good example of this type of motion is the San Andreas Fault which runs through California.
  38. 38. Seismic Waves Earthquakes create seismic waves are just like waves of water moving across the ocean and waves of air moving across a field of wheat.
  39. 39. P Waves The P waves move in a compressional motion similar to the motion of a slinky, while the S waves move in a shear motion perpendicular to the direction the wave is travelling.
  40. 40. Earthquakes generate several kinds of seismic waves including P, for "Primary" and S, for "Secondary" waves. S Waves
  41. 41. Some depend on the amount of damage caused by the earthquake while others depend on the amount of seismic energy emitted by the earthquake. There are two popular earthquake scales. The Mercalli Intensity Scale (intensity / effect of earthquakes on certain locations) The Richter Magnitude Scale (magnitude)
  42. 42. the earliest seismograph was invented in China A.D. 136 by a m an named Choko. Seismograph
  43. 43. Each dragon head held a ball in its mouth, which, when dropped due to the strong shaking of an earthquake, would fall into the open mouth of the frog directly below it. By noting which frogs contained balls after a strong earthquake, it was possible to determine how the Earth had moved in response to the earthquake. early eastern seismoscope consisted of a copper vessel with eight dragon heads attached to it, positioned above eight frogs.
  44. 44. By the end of the 19th century, several European inventors had constructed different seismographs. Most were electromagnetic and operated by suspending a magnetic mass, or pendulum, within an electric coil.
  45. 45. Today's high-technology, digital seismographs record ground shaking over a large band of frequencies and seismic amplitudes. They are called broadband since they record frequencies from thousands of seconds to less than a hundredth of a second.
  46. 46. old seismometers was limited by the amount of movement possible between the mass, or pendulum, and the seismometer housing. Modern seismometers can record a wide range of seismic signals, both very small and very large.
  47. 47. • a conical shaped hill or mountain built by accumulations of lava flows, tephra and volcanic ash. • has its origin from the name of Vulcan, a god of fire in Roman mythology. What is a Volcano?  The processes that create volcanoes and other volcanic structures.
  48. 48. Parts of a Volcano:
  49. 49.  Most volcanoes occur where two plates meet. When two plates move apart causing a gap, hot molten rock - called magma - rises up between them. This type of volcano occurs on the ocean floor and is mostly invisible. If the amount of magma is large enough, it rises above the surface of the ocean and an island is created.If two plates collide and one plate is forced beneath the other plate, the friction makes the first melt and magma rises up. Only a few volcanoes on earth are formed like this, but their eruptions are the most violent and dangerous ones. Sometimes volcanoes also form in the middle of the plates which are called hotspots. These are places that are connected by channels to the hot YouTube - How Volcanoes Fo
  50. 50. This classification is based on the geomorphic form, magma chemistry, and the explosiveness of the eruption. five different types of volcanoes.
  51. 51. Caldera formation
  52. 52.  Least explosive type of volcano.  Produces a very basaltic magma with horizontal flows.
  53. 53.  Shaped like a bowl or shield in the middle with long gentle slopes made by the lava flows.  Built up of successive layers of high viscosity lava flows.  This type of volcano is built slowly and can have multiple vents producing lava flows.
  54. 54.  Largest active volcano in the world.  5 1/2 miles high (3 miles under water and 2 1/2 miles above sea level). Almost 5 miles of this volcanic structure is buried into the Pacific plate below ground level which if included makes this structure about 10 miles in height!  A shield volcano.
  55. 55.  A cone structure built by an accumulation of loose bits of magma called scoria that fall around a vent or crater after being expelled during moderately explosive activity.  A small volcano between 100 and 400 meters tall.  Has steeply sloped sides
  56. 56.  Also known as stratovolcano.  It is a cone shaped mountain with steep, smooth, barren slopes often with a single plume of smoke emitted from a single central vent. It is composed of alternating layers or strata of material created by pyroclastic (lava) flows.
  57. 57.  They form when huge amounts of magma erupts out of sub-surface magma chambers. The removal of magma leaves a void below the surface and the top collapses in to form the caldera. The resulting basin- shaped depression is roughly circular and is usually several kilometers or more in diameter. The lava erupted from caldera volcanoes is very viscous and generally the coolest with temperatures ranging from 650°C to 800°C and is called rhyolitic magma. Although caldera volcanoes are uncommon, they are the most dangerous.  Volcanic hazards from this type of eruption include tsunami from caldera collapse, large pyroclastic surges and widespread ash fall. types of volcano.wmv
  58. 58. • Active volcano – Erupts regularly or showing signs of unrest. • Dormant volcano – also called "Sleeping" volcanoes because it is presently inactive, but could erupt again. • Extinct volcano – has not had an eruption for at least 10,000 years and is not expected to erupt again in a comparable time scale of the future. Volcanic Activity
  59. 59. • hotspot theory- A hotspot is located in the middle of a plate (below it). When the hotspot emits magma, it will form a volcano. As the plate moves, the volcano located on the plate moves together with it. It is then cut off from the magma source which is the hotspot, and it becomes extinct. How do active volcanoes become extinct?
  60. 60. • Phreatic eruption (steam-generated eruptions) • explosive eruption of high-silica lava (e.g.,rhyolite) • effusive eruption of low-silica lava (e.g., basalt), • Pyroclastic flows • lahars (debris flow) • Carbon dioxide emission. Types of volcanic erruption
  61. 61. • Helps in maintaining the biogeochemical cycles • Helps in cooling the atmosphere Effects of volcanic eruptions
  62. 62. • Add nutrients to soil through weathering process of volcanic rock • Create new islands Effects of volcanic eruptions
  63. 63. • Moon – Volcanic features like maria, sign of past lava flow • Venus – 90% basalt Volcanoes on other planetary bodies
  64. 64. • Mars – Four of several extinct volcanoes are Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. Volcanoes on other planetary bodies
  65. 65. • Jupiter – Io-most volcanically active – Europa- its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface(cryovolcanism). Volcanoes on other planetary bodies
  66. 66. REFERENCES • Consulta – Francisco, Ma. Teresa and Francisco, Levi, Physical Science, Ta-Orbitz publication, 2009. • Conceptual Physical Science, 2nd Edition, Hewitt, Paul et. Al., Addison_Wesley Publishing Co. Inc., 1999.