Your SlideShare is downloading. ×
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
GEOG101 Chapt03 lecture
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

GEOG101 Chapt03 lecture


Published on

Published in: Technology
  • Be the first to comment

  • Be the first to like this

No Downloads
Total Views
On Slideshare
From Embeds
Number of Embeds
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

No notes for slide


  • 1. Overview
    • Earth Materials
    • Geologic Time
    • Movements of the Continents
    • Tectonic Forces
    • Gradational Processes
    • Landform Regions
  • 2. Earth Materials
    • Igneous Rocks
    • Sedimentary Rocks
    • Metamorphic Rocks
  • 3. Igneous Rocks
    • Formed by the cooling and solidification of molten rock
    • Magma: molten rock below ground
      • Cooling forms intrusive igneous rocks
        • Granite
    • Lava: molten rock above ground
      • Cooling forms extrusive igneous rocks
        • Basalt, pumice, obsidian
    • Composition of magma and lava plus cooling rate determines the minerals that form
  • 4. Sedimentary Rocks
    • Composed of eroded particles of gravel, sand, silt, and clay
    • Rocks evolve in horizontal strata
      • Compressed by weight of additional deposits and cemented by water and certain minerals
      • Type of sediment determines rock type
        • Large, rounded particles form conglomerates
        • Sand forms sandstone
        • Silt and clay form shale or siltstone
        • Organic materials form limestone or coal
  • 5. Metamorphic Rocks
    • Formed from igneous or sedimentary rocks by earth forces that produce heat, pressure, or chemical reactions
      • Mineral structure is changed
        • Shale becomes slate
        • Limestone may become marble
        • Granite may become gneiss
  • 6. Geologic Time
    • Earth formed about 4.7 billion years ago
    • Theory of continental drift
      • Based on early 20 th -century work of Alfred Wegener
      • All land masses were once united in a supercontinent; continents drifted apart over many millions of years
        • Pangaea: “all Earth”
      • Forerunner of plate tectonics theory
  • 7. Movements of the Continents
    • Plate tectonics theory
      • Asthenosphere
        • Partially molten layer above the core and lower mantle
      • Lithosphere
        • Outermost layer of the earth (the crust and upper mantle)
        • 12 large and numerous small plates that slide or drift slowly over the asthenosphere
          • May be due to convection of molten material in asthenosphere
  • 8. Movements of the Continents
    • Divergent plate boundaries
      • Plates move away from each other
    • Transform boundaries
      • One plate slides horizontally past another
    • Convergent boundaries
      • Plates move toward each other
        • Subduction may occur
          • One plate is forced beneath another
    • Earthquakes and volcanic activity may occur in the vicinity of plate boundaries
      • Ring of Fire
  • 9. Tectonic Forces
    • Diastrophism
      • Earth force that folds, faults, twists, compresses rock
    • Volcanism
      • Earth force that transports subsurface materials to or toward the surface of the earth
  • 10. Diastrophism
    • Broad warping
      • Bowing of a large region of the earth’s surface
    • Folding
      • Layers of rock are forced to buckle
    • Faulting
      • Rock is broken or fractured
        • Escarpments, rift valleys
      • Earthquake
        • Movement along a fault or point of weakness
      • Tsunami
        • Sea waves generated by an earthquake, volcanic eruption, or underwater landslide
  • 11. Volcanism
    • Usually at or near plate intersections
    • Also at hot spots
    • Strato or composite volcano
      • Explosive, steep sides
    • Shield volcano
      • Non-explosive, gently sloping
    • Magma may not reach the surface
    • Lava may flow through fissures or fractures without forming a volcano
  • 12. Gradational Processes
    • Reduction of the land’s surface
      • Weathering
      • Mass movement
      • Erosion
  • 13. Weathering
    • Processes that fragment and decompose rock
    • Mechanical
      • Physical disintegration
        • Frost action
        • Salt crystals
        • Root action
    • Chemical
      • Decomposition as a result of chemical reactions
        • Oxidation
        • Hydrolysis
        • Carbonation
  • 14. Mass Movement
    • Downslope movement of material due to gravity
      • Avalanches
      • Landslides
      • Soil creep
    • Talus
      • Landform created by the accumulation of rock particles at the base of hills and mountains
  • 15. Erosional Agents and Deposition
    • Wind, water, and glaciers
      • Carve, wear away, and remove rock and soil particles
    • Material is deposited in new places
      • New landforms are created
  • 16. Running Water
    • Most important erosional agent
    • Ability to erode depends upon:
      • Amount of precipitation
      • Length and steepness of the slope
      • Kind of rock and vegetation cover
    • Load of a stream
      • Materials transported by a stream
      • Decline in velocity results in deposition
        • Deltas: where streams meet bays, oceans, and lakes
        • May be deposited in adjacent plains (floodplain)
  • 17. Stream Landscapes
    • Humid areas
      • Waterfalls
      • V-shaped channels
      • Floodplains
      • Meandering streams
      • Oxbow lakes
      • Natural levees
    • Arid areas
      • Lack of vegetation increases erosional forces
      • Playas
      • Alluvial fans
      • Arroyos
      • Washes
      • Buttes and mesas
  • 18. Groundwater
    • Aquifer
      • Porous underground structure bearing water
    • Water table
      • Upper level of the water within an aquifer
      • Ponds, lakes, marshes, and streams form when land surface dips below the water table
  • 19. Groundwater
    • Solution
      • Chemical process by which groundwater (particularly when combined with CO 2 ) dissolves soluble materials
      • Significant effect on limestone
        • Underground caverns, stalactites, stalagmites, sinkholes
    • Karst topography
      • Limestone region marked by sinkholes, caverns, and underground streams
  • 20. Glaciers
    • Huge mass of slowly moving land ice
    • Covered a large part of the earth as recently as 10,000-15,000 years ago
    • Form only where annual snowfall exceeds annual snowmelt and evaporation
      • The weight of the snow causes it to compact at the base and form ice
        • Ice at the bottom becomes like toothpaste and moves slowly
  • 21. Glaciers
    • Continental glaciers
    • Mountain glaciers
    • About 10% of the earth’s land is under ice
    • Glaciers change landforms by erosion
      • Scour the land as they move
    • Glaciers create landforms when they deposit debris they have transported
      • Till consists of rocks, pebbles, silt
  • 22. Glacial Landforms
    • Erosional
      • Glacial troughs
      • Fiords
      • Tarns and cirques
      • Arêtes
    • Depositional
      • Moraines
      • Eskers
      • Drumlins
      • Outwash plains
  • 23. Waves, Currents, and Coastal Landforms
    • Cliffs
      • Formed by wave action when land at the coast is well above sea level
    • Beaches and spits
      • Formed by the deposition of sand grains
      • Longshore currents transport sand
    • Sandbars
      • Formed by sand deposited by the backwash of waves
      • May expand to enclose lagoons or inlets
        • Salt marshes may develop
  • 24. Waves, Currents, and Coastal Landforms
    • Coral reefs
      • Composed of coral organisms growing in shallow tropical water
      • Develop short distances offshore
    • Atolls
      • Reefs formed in shallow water around a volcano that has since been covered or nearly covered by water
  • 25. Wind
    • Most significant in dry climates
      • Limited vegetation leaves exposed particles subject to movement by wind
    • Dunes
      • Produced by wind-driven sand
    • Loess
      • Deposit of windblown silt
      • Rich soils usually form from loess deposits
  • 26. Landform Regions
    • Large section of the earth’s surface where a great deal of homogeneity occurs among the types of landforms that characterize it
      • Mountains
      • Plains
      • Plateaus