When Earth’s crust bends, folds occur
Folding occurs under compression when forces
act towards each other, such as when plates collide.
Definitions
Compression
·Is a process of forcing something
into smaller compass, reducing it in volume by pressing it together
Tension
·Is a pulling
force, tending to stretch, to cause an extension of a body or to restore the
shape of an extended elastic object
A fold is a bend in the
rock strata.
Folding: Is a type of earth
movement resulting from the horizontal compression of rock layers by
internal forces of the earth along plate
boundaries.
Parts of a fold
:
layers of rocks of continental crust bent in upfolds
called anticlines & downfolds called synclines.
2 sides of a fold are called the limbs.
Generally, anticlines form fold
mountains & synclines form valleys
There are 2 main fold mountains systems in
the world:
Old and young fold mountains, based on their
geological age.
A) The old Caledonian fold mountains (formed
400 million years ago)
