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River rejuvenation
| Question | Answer |
|---|---|
| Define river rejuvenation: | When a river regains energy in the middle or lower course due to isostatic adjustment and starts to erode again |
| Isostasy | The vertical movement of the earths crust |
| Isostatic adjustment | the vertical movement of the earths crust in response to large amounts of pressure like glaciers and subsequently the absence of them. |
| Cause1 of rejuvenation: | Land was compressed by glaciers during the glaciation period now the ice has melted away thousands of years later, the crust is rebounding to its original level this is called isostatic adjustment. This causes a drop in the relative sea level. |
| Cause 2 of rejuvenation: | Eustatic fall in sea levels as global cooling occurs and icecaps form |
| Knickpoints | A sudden change or drop in the river profile due to river rejuvenation marking the point at which the old river profile meets the new |
| Incised meander | Meanders of a river that have been eroded vertically due to isostatic adjustment and have been cut into the flood plane. |
| Paired terrace | remnants of former flood planes left high and dry due to a drop in the base level of a river |
| examples of a paired terrace | Terenure Co. Dublin the dodder river |
| example of knickpoints | R Shannon south of lough derg |
| example of incised meanders | R Barrow bellow St Mullins |
Created by:
serrraphina
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