Geology Lesson 1

• Geology


  The study of the Earth and its system
• Branches of Geology

  • Structural Geology
  • Sedimentology-sedimentary petrography
  • Stratigraphy
  • Mineralogy-Petrography
  • Mineralogy
  • Petrography
  • Ore deposits-Geochemistry
  • Mineral deposits
  • Geochemistry
  • Petroleum Geology
  • Applied Geology
  • Engineering Geology
  • Hydrogeology
  • Mathematical Geology
• Geological Engineering


  Provides the use of geological data for practical engineering purposes
• Continental Drift


  • Early hypothesis that continents move slowly across Earth's surface over millions of years
  • Evidence: continents fit together like a jigsaw puzzle, matching coastlines and geological formations, fossils of same plants and animals on continents now far apart
  • Wegener could not explain the force causing continents to move
• Plate Tectonics


  Explains how plates (large bodies of rock) move slowly around the earth on partly melted rock
• Plates


  • Large section of the earth's crust that moves as one unit
  • There are 8 large plates and several smaller plates
• Types of plate movement

  1. Convergent: where two plates move together

  2. Divergent: where two plates are drifting apart

  3. Sliding: where the plates slide past one another
• Fault


  The place where two plates meet
• Volcano


  • An opening in the earth's surface
  • Magma (melted rocks) from the mantle sometimes pushes upward through cracks in the crust
  • Magma builds up pressure and then erupts through the main vent
• What happens after a volcano erupts

  1. Magma explodes through the main vent

  2. A deep hole called crater is often left on the top

  3. Erupting magma is called lava

  4. Gases, volcanic bombs, ash, and melted rock also burst from the volcano

  5. Lava layers and ash layers build up around the outside
• Hawaii was formed by volcanoes erupting in the Pacific Ocean
• Earthquake


  • Sudden shifts in the earth's rock layers cause earthquakes
  • The focus, or epicenter, is where the earthquake begins
  • Plates can meet in a rubbing, spreading, or pushing way
• What causes earthquakes

  1. Sudden shifts in the earth's rock layers

  2. Plates can meet in a rubbing way (sliding), spread away from each other (divergent), or meet in a pushing way (convergent)
• New plates can be created during an earthquake (especially at mid-ocean ridges)
• Seismograph


  Used to measure earthquakes
• Richter scale


  Used to give earthquakes a number
• People cannot feel earthquakes between a 1-2 on the Richter scale
• An earthquake that receives a 7-8 on the Richter scale destroys buildings
• Earthquakes


  Can create land by creating mountains and valleys, or destroy land, homes, and structures
• Igneous rocks


  Means "fiery"
• Metamorphic rocks


  Means "change"
• Sedimentary rocks


  The sediment builds up over many years and becomes cemented together
• Physical (mechanical) weathering


  1. Happens when the earth's crust is exposed to water, air, and changes in temperature

  2. Rocks can wear away, making smaller rock pieces or sediments

  3. Freezing water expands and can cause rocks to crack
• Chemical weathering


  1. Happens when gases in the air chemically react with other elements and minerals

  2. Acid rain can dissolve limestone rocks
• Erosion


  • The carrying away of weathered rock by gravity, water, wind, and ice
  • Can wash away boulders and mountains
• Examples of Weathering and Erosion

  • Sea cliffs: form when a rocky shore erodes at approx. the same rate throughout an area, resulting in a steep walled structure
  • Slot Canyons: caused by flash floods
• Mt. Everest is the highest place on earth - 29,032 feet high
• The Mariana Trench is the lowest place on earth - 36,069 feet deep
• The Dead Sea is the lowest place on the surface of the earth - 1,388 feet below sea level
• Galesnjak, Croatia is the most perfect heart-shaped island on earth
• Core - The core consists of two parts: an inner solid core and an outer liquid core.
• Mantle - lies beneath the crust and extends to about halfway down into the earth.
• The Earth's crust is the outermost layer, composed mainly of silicate minerals.
• Igneous rocks are formed from the solidification of molten rock material.
• Plate tectonics refers to the movement of large plates on the Earth's surface.
• Igneous rocks are formed by the cooling and solidification of magma or lava.
• Igneous rocks form when molten material cools and solidifies either below ground (intrusive) or on the surface (extrusive).