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Lecture1_.pptx

  1. 1. LECTURE 1
  2. 2. A basin is a depression, or dip, in the Earth's surface. Basins are shaped like bowls, with sides higher than the bottom.
  3. 3. Cont.. Basins are formed by forces above the ground (like erosion) or below the ground (like earthquakes). They can be created over thousands of years or almost overnight.
  4. 4. Bohinj Valley The Julian Alps rise above the crystal-clear waters of Lake Bohinj in Bohinj, Slovenia. Like many lake basins, Lake Bohinj was carved out as a glacier cut through the landscape. Restrictions on development around the lake help keep the glacial valley pristine.
  5. 5. Yellowstone Geyser Basin A split in the Earth's crust leads into a geyser basin at Yellowstone National Park, Wyoming. More than two thirds of the world's geysers are located in Yellowstone, which lies above a huge collapsed volcano. Most Yellowstone geyser basins form in valleys between ancient lava flows and glacial moraines.
  6. 6. Bisti Badlands Bold bands of sandstone and darker shale stripe the Bisti Badlands in New Mexico's San Juan Basin. Uranium, oil, gas, and billions of tons of coal lie beneath the region, also known for extensive dinosaur fossil beds.
  7. 7. Badwater Basin Badwater Basin, located in Death Valley National Park, California, was created by flash floods and excessive heat. Measured at 86 meters (282 feet) below sea level, Badwater Basin is the lowest-lying point in theWestern Hemisphere.
  8. 8. Major types of basins  The major types of basins are : River drainage basins, Structural basins, Sedimentary basins,  Ocean basins.
  9. 9. River drainage basins A river drainage basin is an area drained by a river and all of its tributaries. A river basin is made up of many different watersheds.
  10. 10. Cont..
  11. 11. Cont..  A watershed is a small version of a river basin. Every stream and tributary has its own watershed, which drains to a larger stream or wetland. These streams, ponds, wetlands, and lakes are part of a river basin. The Mississippi River basin in the U.S., for instance, is made up of six major watersheds: the Missouri, Upper Mississippi, Ohio, Tennessee, Lower Mississippi, and Arkansas-Red-White Rivers.
  12. 12. Cont..  Every river is part of a network of watersheds that make up a river system’s entire drainage basin. All the water in the drainage basin flows downhill toward bigger rivers. The Pease River, in northern Texas, is part of the Arkansas-Red- White watershed. It is a tributary of the Red River. The Red River is a major tributary of the Mississippi River, which flows into the Gulf of Mexico.
  13. 13. Cont..  The Amazon Basin, in northern South America, is the largest in the world. The Amazon River and all of its tributaries drain an area more than 7 million square kilometres (about 3 million square miles).
  14. 14. Structural Basins  Structural basins are formed by tectonic activity. Tectonic activity is the movement of large pieces of the Earth’s crust, called tectonic plates. Tectonic activity is responsible for such phenomena as earthquakes and volcanoes. The natural processes of weathering and erosion also contribute to forming structural basins.
  15. 15. Structural basin
  16. 16. Cont..
  17. 17. Cont..  Structural basins are usually found in dry regions.  Some structural basins are known as endorheic basins. Endorheic basins have internal drainage systems. This means they don’t have enough water to drain to a stream, lake, or ocean. The water that trickles into other types of basins evaporates or seeps into the ground.
  18. 18. Cont..  When enough water collects in an endorheic basin, it can form a very salty lake, such as the Dead Sea, between Palastian and Jordan. While water evaporates into the atmosphere, minerals remain. The remaining water becomes even saltier. The Dead Sea is one of the saltiest natural body of water on Earth. Its shore, about 400 meters (1,300 feet) below sea level, is Earth’s lowest dry point.
  19. 19. Sedimentary basins  Sedimentary basins are a type of structural basin that aren’t shaped like typical basins, sometimes forming long troughs. Sedimentary basins have been filled with layers of rock and organic material over millions of years. Material that fills up the basin is called sediment fill.
  20. 20. Sedimenrty basin
  21. 21. Cont..  Sedimentary basins are key sources of petroleum and other fossil fuels. Millions of years ago, tiny sea creatures called diatoms lived and died in ocean basins. Eventually, these ancient oceans dried up, leaving dry basins. The remains of the diatoms were at the bottom of these basins. The remains were crushed under billions of tons of sediment fill, over millions of years. In the right conditions, the pressure of the sediment fill turns the diatom remains into petroleum.
  22. 22. Cont..  The Niger Delta sedimentary basin, in the countries of Nigeria, Cameroon, and Equatorial Guinea, is one of the most productive petroleum fields in Africa. In North America, the Western Canadian Sedimentary Basin is one of the continent's largest suppliers of gas and coal.
  23. 23. Ocean Basins  Ocean basins are the largest depressions on Earth. Edges of the continents, called continental shelves, form the sides of ocean basins.
  24. 24. Cont….  There are five major ocean basins, coordinating with the major oceans of the world: the Pacific basin, the Atlantic basin, the Indian basin, the Arctic basin, and the Southern basin. Many smaller basins are often considered oceanic basins, such as the North Aleutian Basin, between the Pacific and Arctic Oceans.
  25. 25. Ocean basin
  26. 26. Cont..  Tectonic activity constantly changes ocean basins.  Seafloor spreading and Subduction are the most important types of tectonic activity that shape ocean basins.
  27. 27. Face facts –Activity What's your basin? Everyone lives in a watershed or river basin, even if they don't live near water. What is the name of the watershed or river basin you live in?

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