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Tuesday 11-12-13

Tuesday 11-12-13. Update SN Grade Types of Rocks WS Weathering & Erosion Notes. Weathering and Erosion Weathering Weathering is breaking down and wearing away of rock material. Climates affects the rate of weathering:. 1. Hot damp conditions tend to rot material quicker .

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Tuesday 11-12-13

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  1. Tuesday 11-12-13 • Update SN • Grade Types of Rocks WS • Weathering & Erosion Notes

  2. Weathering and Erosion Weathering Weathering is breaking down and wearing away of rock material.

  3. Climates affects the rate of weathering: 1. Hotdamp conditions tend to rot material quicker Inca city of Machu Picchu in the Andes Mountains of Peru Mayan City of El Mirador in the rainforest of Belize. 2. Cooler dry conditions take a longer time to rot.

  4. Types of Weathering • Physical • Chemical

  5. Physical or Mechanical Weathering The breaking up of rock material into smaller pieces is physical or mechanical weathering. There is NOTa change in the chemistry (composition) of the rock.

  6. Types of Physical or Mechanical Weathering Abrasion- works like sand paper and wears the rock down by ‘rubbing’ water, ice, sand or wind across it. Balancing rocks of Zimbabwe, Africa Dust Storm in New Mexico

  7. b.Temperature – a significant difference between hot and cold temperatures over a period of time. Rock spikes in Wyoming

  8. Exfoliation domes at Enchanted Rock, Texas c. Frost action – the continuous freezing and melting of water

  9. d. Gravity – pulls rock material down Talus slopes in the Sierra Madres. Land slide in Peru

  10. e. Organic activity – burrowing animals and root pry. Worm tubes from the Sea of Cortez Root pry – Camp Goddard, Oklahoma

  11. Chemical Weathering • The breaking down of the composition of a rock into a new and different substance is chemical weathering. • Types of Chemical Weathering • a. Oxidation – the combining of elements (like iron) reacting with oxygen; ‘rusting of rock’- rock turns red. Eastern Tennessee Rusted Hematite

  12. Acids: Rock reacts with water, gases and solutions to form acids which can add or remove elements from minerals Carlsbad Caverns, New Mexico: carbonic acid

  13. Water seeping from a historic gold mine, Reefton, New Zealand has elevated arsenic and antimony. The Parthenon in Greece shows discoloration and chemical weathering effects from air pollution and acid rain.

  14. Erosion Garden of the Gods, Colorado

  15. The transfer of rock material to another location is erosion. The 5 agents of erosion • Running water Groundwater • Glaciers Wind • Ocean waves and currents (beach/shoreline)

  16. Erosion is a force that happens as a result of 2 factors of motion 1. Gravity – downward pull 2. Momentum – speed/velocity

  17. Gravity and momentum interact to carve out and build up the earth’s surface by….. 1. Erosion – carving out process 2. Deposition – building up process

  18. I. Wind Erosion & Deposition Wind picks up dry particles and hurls them along, blasting them against exposed rock - the process is called sand blasting. In arid (dry) landscapes the primary erosional force is wind. Landscape Bridge, Arches National Park, Utah

  19. Shoulder partners:1. What feature was caused by wind erosion?2. Predict how this feature will continue to change with erosion. Holes in the rocks • Hole will get bigger • Gravity might pull it down. Landscape Bridge, Arches National Park, Utah

  20. The most common deposits of wind are sand dunes. Particles of sand are carried along and deposited by the wind. They move over the ground as small ripples and larger dunes. NASA Satellite view of White Sands. Depositional feature: sand dunes. White Sands National Monument, New Mexico

  21. Shoulder partners discuss and name thedepositional features below. Sand dunes & Sand bar formation

  22. Shoulder partners 1. What is the difference between summer and winter erosion? More erosion in the winter.

  23. II. Groundwatererosion is carried out by 3 processes. Water percolates through rock and dissolves it. (weathering) Groundwater Dissolved rock is moved as it drips through Dissolved rock is then deposited. Natural Bridge Caverns, San Antonio, Texas

  24. Shoulder partners discuss and name the erosional and depositional features below. erosional feature – dissolved rocks dripping depositional feature – dissolved limestone is redeposited to form stalagmites and stalactites

  25. III.Glaciers, “rivers of ice”, creep down from mountains as a result of the pull of gravity, and have a tremendous influence on the earth’s surface. Glaciers Weight of the glacier exerts and great deal of pressure causing the ice to move like putty. The great weight grinds out the floor and sides and bulldozes the debris down the slope. This process created the Great Lakes. McGinnis Glacier, Alaska Range, Alaska

  26. As a glacier slowly retreats, it leaves behind the material it ‘bulldozed’ as it moved down the mountain. This material is called moraine This process created New York’s Manhattan Island. Hubbard Glacier, Alaska

  27. Shoulder partners discuss and name the erosional and depositional features below. erosional feature – bulldozing the debris down the slope and cutting a U shaped basin. (depression on Earth’s surface) depositional feature – moraine – debris left behind

  28. IV. Running water - Rivers Amazon River, Brazil, South America

  29. Rivers are flowing bodies of waters There are rivers on every continent (except Antarctica). Rivers are an important part of the Earth's water cycle – they are runoff. Runoff sculpts the surface of earth as it transports large amount of water and dirt to the ocean

  30. The early course of a river (the youngest part) is marked by greater momentum (speed) due to the steeper slope and gravity. Rivers generally start at a high elevation and flow downward to sea level. They may begin as snow melt or a natural spring. Creates a “V” Shape Source of the Mississippi River at Lake Itasca, Minnesota Snake River Canyon, Oregon

  31. As the river ages it stretches across flatter land. With the decreased slope the river’s path develops bends and curves called meanders Mississippi River as it flows through the Great Plains

  32. Oxbow lakes are meanders that are cut off from the main channel. _____________cuts on the outside of the meander until the meander is cut off. Erosion _____________eventually seals off the meander leaving a ‘lake’ behind. Deposition The lake will eventually dry up – becoming a swamp and then dry land.

  33. The mouth of a river is where it flows into a large body of water.. At the mouth of the river, mud is _________ forming a new land mass called the delta. Alluvial Fan of Delta deposited Mississippi River Delta. Louisiana

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