Presentation on theme: "Weathering, Erosion, and Plate Tectonics"— Presentation transcript:
1Weathering, Erosion, and Plate Tectonics The creation of Earth’s Face
2QuestionsWhat forces and phenomena create the different features of the earth?What are tectonic plates?What are the three major Types of Plate Boundaries?What are the two external processes that change the earth’s surface?What are the different types of Weathering and Erosion?
3Forces that change the Earth’s Surface There are two major geological processes that create features on the earth:Faulting and Plate TectonicsWeathering and ErosionThey both take a long time to change the earth.Remember, nothing drastic on earth happens at human speeds.
4Plate TectonicsHuge volumes of heated and molten rock moving around the earth’s interior form massive solid plates that move extremely slowly across the earth’s surface.Tectonic plates: huge rigid plates that are moved with convection cells or currents by floating on magma or molten rock.
6Plate Movement Tectonic Plates move in 1 on four ways. Spreading, or moving apartSubduction, or diving under another plateCollision, or crashing into one anotherSliding past each other in a shearing motion
7The Earth’s Major Tectonic Plates The extremely slow movements of these plates cause them to grind into one another at divergent plate boundaries, move apart at convergent plate boundaries and slide past at transform plate boundaries.Figure 15-4
8Figure 15.4Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on?Fig. 15-4, p. 338
9INDIA-AUSTRALIAN PLATE EURASIAN PLATENORTH AMERICAN PLATEANATOLIAN PLATEJUAN DE FUCA PLATECARIBBEAN PLATECHINA SUBPLATEARABIAN PLATEAFRICAN PLATEPHILIPPINE PLATEPACIFIC PLATESOUTH AMERICAN PLATENAZCA PLATEINDIA-AUSTRALIAN PLATESOMALIAN SUBPLATEFigure 15.4Natural capital: the earth’s major tectonic plates. The extremely slow movements of these plates cause them to grind into one another at convergent plate boundaries, move apart from one another at divergent plate boundaries, and slide past one another at transform plate boundaries. QUESTION: What plate are you floating on?ANTARCTIC PLATEDivergent plate boundariesConvergent plate boundariesTransform faultsFig. 15-4a, p. 338
10GEOLOGIC PROCESSESThe San Andreas Fault is an example of a transform fault.A fault Line is created when rocks meet and lack flexibility. They crack under pressure and the fracture is called a FAULT.Figure 15-5
11Results of Movement Earthquakes are a result of plate movement. The Richter Scale is used to measure the intensity of an earthquake.Tsunamis can result from earthquakes originating in the ocean.Volcanoes are often located along the boundaries of tectonic plates.Magma, gases, ash, and dust explode out of these vents in the earth’s surface.Ring of Fire is located along the rim of the Pacific Ocean and contains most volcanoes.
13Wearing Down and Building Up the Earth’s Surface Weathering is an external process that wears the earth’s surface down.Figure 15-6
14Weathering Three types of weathering: Physical Chemical Biological Big Rock becomes Small Rock due to wind, rain, and frost wedging.Frost wedging occurs when water freezes in between the pores of large sedimentary rocks.ChemicalWhen a chemical reaction degrades or decomposes a rock.More common with rocks containing carbon and oxygen, like limestone.BiologicalConversion of Rock and Minerals into smaller particles due to living thing.Lichens, Tree Roots, Earthworms.
15Parent material (rock) Biological weathering (tree roots and lichens)Chemical weathering (water, acids, and gases)Physical weathering (wind, rain, thermal expansion and contraction, water freezing)Figure 15.6Natural capital: physical, chemical, and biological processes can weather or convert rock into smaller fragments and particles. It is the first step in soil formation.Particles of parent materialFig. 15-6, p. 340
16ErosionErosion is another major external factor that changes the surface of the earth.Erosion is different from weathering because erosion deposits materials from one place to another.Four major examples of erosion:Glacial Movement and MeltMass WastingWater ErosionWind Erosion
17Glacial Movement and Mass Wasting The Movement of Glaciers grind away mountainsides and form basins to capture melted ice waterThe Great Lakes were formed using this method.Mass WastingWhen Rock and soil masses become detached from underlying material and move downhill under the influence of gravity.Rockslides, Mudslides, and LandslidesClearing of Trees and other vegetation increase Mass Wasting Occurrences.
18Water and Wind Erosion Water Erosion Wind Erosion Water picks up material and moves it down stream.Waves can also reduce or increase beaches.Wind ErosionWind transports and deposits sediments.Wind speeds must reach a minimum of 11 miles per hour before sediment can be moved.