Describe The Impact Of Folding And Faulting On Landscape Development

Question 1

Folding and Faulting impact on landscape development

Intro

Answer 1

-In this answer i will be discussing how folding and faulting impacted the development of the Irish landscape

• A fold is a bend or curve in the stratified rocks of the earths crust
• A fault is a crack or fracture in the earths crust

-There are 3 types of forces involved:
Compression squeezes and shortens rock, converging plate movement, results in folding and/or faulting

Tension stretches rock, diverging plate movement, results in faulting

Shearing fractures the rock and pushes sections past one another, convergent and transform plate movement, results in faulting

Question 2

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Answer 2

• Most faulting occurs at convergent plate boundaries, as plates collide rocks are compressed and squeezed together
• The crust crumbles forming folds, occurs mostly in sedimentary rocks as they’re weaker and more flexible
• When rocks are compressed, the layers are pushed up to form anticlines and pushed down to form synclines
• There has been 2 major fold mountain building periods in Ireland Caledonian and Armorican

-Caledonian 400MYA, American + Eurasian plate collided, Continental to continental boundary, SW—NE trend
When they first pushed up they were higher than the Alps, been reduced by weathering and Erosion exposing the igneous rock to the surface e.g Dublin and Wicklow mountains

-Armorican 250MYA, African and Eurasian plate collided, E—W trend, horizontal layers of Shale, Limestone and Sandstone were buckled up
This is being continuously eroded and weathered exposing the ORS underneath
E.g Ridge and valley landscape in Munster, MacGillycuddy’s Reeks and Galtee Mountains

Question 3

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Answer 3

-When rocks are subjected to too much stress, they eventually fracture, if there’s movement of rock along one or both sides of a fracture its a fault
Faults normally take place along zones of weakness in the crust
There are 3 main types of faults:
.Normal Fault
.Tear Fault
.Reverse Fault

-A normal fault results from tension in the crust, the crust is extended until a fault eventually occurs, the movement is vertical where one block of crust slips downwards relative to the other, results in a steep slope, exposed section is called a scarp
In Ireland the Ox mountains formed of igneous rock, the limestone to the North and South slipped down

-A tear fault is a fracture in the rock, it happens when one block moves sideways or horizontally past another block instead of up and down
The Leannan fault Co. Donegal is thought to be an extension of the Great Glen Fault in Scotland
-Zones of either side of this fault contain badly crushed rocks, weathering and erosion are very effective, The Leannan river has cut very deeply into Leannan Fault

A reverse fault is the opposite of a normal fault, it results when rocks in the crust are subjected to compression during earth movements, rocks fracture due to great pressure
One block is forced forward and up, rides over the other block and crust is shortened
E.g the line from Killarney to Mallow

Question 4

Diagram of a reverse fault

Answer 4

Question 5

Diagram of normal fault

Answer 5