Isostatic Essay Flashcards
What is isostacy?
Isostacy is when land rises and falls relative to sea level
Explain Isostacy in further detail
The weight of large ice sheets on the land causes the earths crust to sink into the mantle.
What are local sea level changes?
Only the areas of land affected by this ice may be raised from the sea so that sea level changes are local not global. These local changes are called isostatic sea level changes
What is rejuvenation?
Rejuvenation means to make young again and happens when a rivers base level of erosion either rises or falls.
What does rejuvenation mean for a river?
This means it will begin to flow faster with renewed energy to reach sea level even though it has flowed through its entire course
What is a knickpoint ?
Knickpoints are small waterfalls and rapids that mark the point of rejuvenation.
When can there be several knickpoints?
If rejuvenation has occurred more than once the may be several Knick points. Irish example: river suir
What are river terraces?
River terraces are flat stepped areas on each side of a river valley representing former floodplains example: River Barrow
Explain river terraces in further detail.
Due to rejuvenation, vertical erosion by the river is renewed and the river cuts a new and narrower channel for itself. Leaving former floodplain well out the present day river level.
What are incised/entrenched meanders?
Entrenched meanders are steep sided meanders in the mature and old stage of a river. Example: River Nore
Explain entrenched meanders in more detail.
As the rejuvenated river had more energy it erodes vertically deep into the existing river valley engraving its meandering pattern into the bedrock below.
