Overview <ul><li>Earth Materials </li></ul><ul><li>Geologic Time </li></ul><ul><li>Movements of the Continents </li></ul><...
Earth Materials <ul><li>Igneous Rocks </li></ul><ul><li>Sedimentary Rocks </li></ul><ul><li>Metamorphic Rocks </li></ul>
Igneous Rocks <ul><li>Formed by the cooling and solidification of molten rock </li></ul><ul><li>Magma: molten rock below g...
Sedimentary Rocks <ul><li>Composed of eroded particles of gravel, sand, silt, and clay </li></ul><ul><li>Rocks evolve in h...
Metamorphic Rocks <ul><li>Formed from igneous or sedimentary rocks by earth forces that produce heat, pressure, or chemica...
Geologic Time <ul><li>Earth formed about 4.7 billion years ago </li></ul><ul><li>Theory of continental drift </li></ul><ul...
Movements of the Continents <ul><li>Plate tectonics theory </li></ul><ul><ul><li>Asthenosphere </li></ul></ul><ul><ul><ul>...
Movements of the Continents <ul><li>Divergent plate boundaries </li></ul><ul><ul><li>Plates move away from each other </li...
Tectonic Forces <ul><li>Diastrophism </li></ul><ul><ul><li>Earth force that folds, faults, twists, compresses rock </li></...
Diastrophism <ul><li>Broad warping </li></ul><ul><ul><li>Bowing of a large region of the earth’s surface </li></ul></ul><u...
Volcanism <ul><li>Usually at or near plate intersections </li></ul><ul><li>Also at hot spots </li></ul><ul><li>Strato or c...
Gradational Processes <ul><li>Reduction of the land’s surface </li></ul><ul><ul><li>Weathering </li></ul></ul><ul><ul><li>...
Weathering <ul><li>Processes that fragment and decompose rock  </li></ul><ul><li>Mechanical </li></ul><ul><ul><li>Physical...
Mass Movement <ul><li>Downslope movement of material due to gravity </li></ul><ul><ul><li>Avalanches </li></ul></ul><ul><u...
Erosional Agents and Deposition <ul><li>Wind, water, and glaciers   </li></ul><ul><ul><li>Carve, wear away, and remove roc...
Running Water <ul><li>Most important erosional agent </li></ul><ul><li>Ability to erode depends upon:   </li></ul><ul><ul>...
Stream Landscapes <ul><li>Humid areas </li></ul><ul><ul><li>Waterfalls </li></ul></ul><ul><ul><li>V-shaped channels </li><...
Groundwater <ul><li>Aquifer </li></ul><ul><ul><li>Porous underground structure bearing water </li></ul></ul><ul><li>Water ...
Groundwater <ul><li>Solution </li></ul><ul><ul><li>Chemical process by which groundwater (particularly when combined with ...
Glaciers <ul><li>Huge mass of slowly moving land ice </li></ul><ul><li>Covered a large part of the earth as recently as 10...
Glaciers <ul><li>Continental glaciers </li></ul><ul><li>Mountain glaciers </li></ul><ul><li>About 10% of the earth’s land ...
Glacial Landforms <ul><li>Erosional </li></ul><ul><ul><li>Glacial troughs </li></ul></ul><ul><ul><li>Fiords </li></ul></ul...
Waves, Currents, and Coastal Landforms <ul><li>Cliffs </li></ul><ul><ul><li>Formed by wave action when land at the coast i...
Waves, Currents, and Coastal Landforms <ul><li>Coral reefs  </li></ul><ul><ul><li>Composed of coral organisms growing in s...
Wind <ul><li>Most significant in dry climates </li></ul><ul><ul><li>Limited vegetation leaves exposed particles subject to...
Landform Regions <ul><li>Large section of the earth’s surface where a great deal of homogeneity occurs among the types of ...
Upcoming SlideShare
Loading in...5
×

GEOG101 Chapter 3 Lecture

958

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
958
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
19
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

GEOG101 Chapter 3 Lecture

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

    Clipping is a handy way to collect important slides you want to go back to later.

×