Isostacy Flashcards
What is isostatic rebound?
When weight is removed crossed rises upward and cause a sea level to fall relative to the land
What is isostasy?
It refers to the vertical movement of the Earth crust, which causes it to rise or fall relative to the sea level
What is isostatic equilibrium?
It is the sinking of crust due to added weight and sea level rises relative to the land
What is the most common cause of isostatic movement?
Glaciation
When did the last ice age end in Europe?
10,000 years ago
What is the lowest point where erosion occur is called?
Base level
What is fluvial readjustment?
As isostatic rebound occurs reverse a road downward to reach its base level again
What is river rejuvenation?
It is when the velocity of a river increases in its old stage so the river erodes vertically and take some characteristics of the youthful stage
Define a Knick point
It is a sudden drop in the river’s profile usually found in the old stage
Describe a neck point
It occurs due to river rejuvenation and the drop in sea level. Meaning a river has to throw a larger distance to reach the sea giving a renewed ability for vertical erosion.
The river arose at the river mouth and work to speed back up stream by headway erosion cutting a new long profile
The place where the new river profile meets the old one is called a neck point and represent whether the river wants to enter the sea
What does several neck points indicate?
They mark each phase of rejuvenation showing several phrases
Where would you find a neck point?
River barrow County Kilkenny
Define paired terraces
A stepped river Valley found in the mature and all stages of river rejuvenation
Described paired terraces
A rejuvenated river begins to cut down into its existing floodplain and aluminium making a New 🌺 deeper narrow channel using vertical erosion and hydraulic action
So a new floodplain is created a lower level
The original Valley floor and floodplain are left higher above the new floodplain and our senior steps on either side of the rejuvenated river called terraces and they are often seen in pairs so Icalled paired terraces
Define incised
Meanders
Amy Anderson that has eroded deep into the Rivervalley
Describe a in sized meander
If a river has been meandering before rejuvenation then after it is given renewed velocity for vertical erosion so the meander erodes rock deepening the river creating a whining gorge with steep narrow sides
What is an entrenched meander?
It is an incosed meander with steep sided valleys and symmetrical profile
What is an ingrown meander?
They form when vert colour erosion occurs slowly. Lateral erosion on Outer bend forms to Rivercliff and on the inner bend for a gently sloping point bar
Where would you find an in sized man under?
River barrow new ross
What are coastlines of submergence?
River barrow new Ross they occur when the weight of glacier pushes across downward into the mantle so the sea level rises relative to it
What are coastlines of emergence?
They occurred when glaciers melt and this causes the removal of weight with a cross rebounds. The sea is no longer able to erode or along areas it could previously.
What is eustatic movement?
It occurs when there is a global change in sea level most commonly at the beginning and end of ice ages
What are some features of coastlines of emergence?
E.g. when glacier melt
Raised cave, cliff and beach
What are some features of coastlines of submergence
Fjord
Ria
