folding and faulting Flashcards
how does faulting occur
plate collision
what is a symetrical fold
when even pressure is applied from both sides
what are asymetric fold
greater pressure from one side
what is an over fold
• Is formed when larger amounts of pressure are applied to one side of the rock layer. The rock fold is turned over on itself so that one or both limbs dip in the same direction.
what is an overthrust fold
• When the compression of the rock layers is very great, a crack of fault occurs in the fold.
how did the caledonian folding occur
eurasian and american grew closer squashinf terranes together. The in-between ocean floor was subducted under both continents and the seafloor sediments were buckled up to form the sedimentary rocks of the Caledonian Fold Mountains
what are the rocks of the caledonian folding eg granite
heat from thr batholiths changed sandstone to quartzite
erosion exposed these
sub ducted rock melted and formed into magma which entered the crust forming batholiths
what was the armonican foldings
- Occurred around 300 million years ago.
- Mountain ridges trend from north-east to south-west. E.g. Leinster Mountains
- They are very old mountains, they have been worn down and today are rounded in shape.
what was the alpine folding
500 yrs ago
• Mountain ridges run from east to west, e.g. Alps & Himalayas. These are the highest and most jagged mountains in the world because they are so young.
