1 / 39

Agents of gradation

Agents of gradation. Introduction. Gradation changes surface features of the land. It involves erosion, transportation and deposition . It involves process like degradation, aggradations and weathering. Work of river Or Running water. Introduction.

sen
Download Presentation

Agents of gradation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Agentsof gradation

  2. Introduction • Gradation changes surface features of the land. • It involves erosion, transportation and deposition. • It involves process like degradation, aggradations and weathering.

  3. Work of river Or Running water

  4. Introduction • Rivers originate from hills or mountains. • They have different amount of water In different seasons. • Some rivers water through out the year and some don’t.

  5. They are known as perennial and non-perennial rivers. • They are the most powerful agent of gradation. • The work of the running water is also called as fluvial process.

  6. Rivers • It consists of threestages namely - First stage Second stage Third stage

  7. STAGE OF A RIVER FIRST SECOND THIRD

  8. First stage • In the first stage the river has it maximum speed so most of the erosion is done in this course. It forms rapids, waterfalls, gorges, canyon, V-shaped valley and erodes it bed during the upper course. • In the upper course of a river valley the land is highest, steepest and most exposed

  9. Waterfalls • Waterfalls occur where the bed of a river becomes suddenly steepened. • Waterfalls are caused by differences in rock hardness. • E.g.., Niagara falls, the great kaietur falls.

  10. waterfalls

  11. Niagara falls The Niagara Falls are voluminous waterfalls on the Niagara River, straddling the international border between the Canadian province of Ontario and the U.S. state of New York.

  12. Victoria falls The Victoria Falls or Mosi-oa-Tunya(the Smoke that Thunders) is a waterfall located in southern Africa on the Zambezi River between the countries of Zambia and Zimbabwe.

  13. Rapids

  14. Some examples for Rapids

  15. Where a river derives its water from snow-melt mountains and flows through arid areas and is able to maintain its erosive power ,canyons are formed. E.g., grand canyon ,Rhine George etc. Canyons

  16. Gorges

  17. Some valleys have very steep sides and are both narrow and deep. These are called gorges. Some valleys have very steep sides and are both narrow and deep. These are called gorges. Gorges

  18. Swan gorges

  19. Interlocking spurs • An interlocking spur is a natural geographical feature which occurs in a river's upper course, where upward erosion is the dominant force in determining the river's course.

  20. Interlocking spurs

  21. Second stage • In the middle course the river's speed becomes slow that it was in the upper course. The river deposits, erodes all the material along its way. • The main features formed by the river in its middle course are meanders, oxbow lake and flood plain.

  22. Meanders • Meander is a loop-like bent in a river. As a river nears the sea it winds up, forming regular horseshoe shape bends, these bends are called Meanders

  23. Meanders

  24. Flood plain is a broad flat river valley in the lower reaches of a river. A river often flows over wide plains of sediments or alluvium. This alluvium is washed down the hills and spread out over the valley floor in times of flood Flood plains

  25. Flood plains

  26. Oxbow lake is a crescent - shaped lake on a river floodplain. As the river wears away on the outside bend of the meander, the neck of the meander gets continually narrower. Ox-bow lake

  27. Ox-bow lake

  28. Third stage • In the lower course of a river, the valley floor is extremely gently sloped. The river spreads over a large and its speed becomes very slow. Hence the river is not able to carry the sediments with it • In this course the river generally deposits and very less erosion and transportation work takes place. • The main features made by the river in its lower course are distributaries, delta and estuaries.

  29. Distributaries

  30. Distributaries • By the huge amount of deposition taking place the river channel get obstructed resulting to the formation of distributaries. The distributaries branches off from the main river take the water away from the river.

  31. Distributaries

  32. Delta • A delta is a landform that is created at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river.

  33. Delta Arcuate delta Bird’s foot delta

  34. Nile delta

  35. Estuaries

  36. Estuary • An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. • E.g., Klamath river

  37. Estuaries

  38. Thank you for seeing power point project This project is created by Group-1

More Related