Plate Tectonics - How Mountains are Made

how do mountains form we see them in

just a moment of time but they form over

millions of years mountain belts extend

for hundreds even thousands of

kilometres and their structures

penetrate deep into the earth so their

size and age make their formation

difficult to understand French geologist

Jacques Malave build sand models that

mimic the formation of mountain belts

and allow scientists to study this

complex process

don't poor Taniya in order for an

experimental that runs for only a few

minutes but represents natural phenomena

that had an over many tens of millions

of years in form italia we have to

choose a material on this deformation

behavior don't does not depend on time

your subject and climate is and is a

very good material is for simulating

Rock deformation in the experiment the

different stratigraphic layers which

represent the sediments and the

continental crust have different

mechanical properties regime we mix the

sand grains for the finer powder muscle

which increases the sands resistance to

deformation of the key thus we have

heterogeneous material made up of more

resistant layers and less resistant

layers mountain belts are created when

continents collide in this experiment we

see two continents separated by an ocean

now watch what happens as the plates

converge as one plate subducts or dives

beneath the other the ocean basin closes

the continental crust which is lighter

than oceanic crust cannot be subducted

instead as the continents collide the

crust thickens and is forced up note how

the sand is folded and faulted we see

similar structures in the rocks in

kontin's one important factor not

accounted for in this model is erosion

erosion exposes the deformed rocks that

were once deeply buried in the mountain

belt the green sand represents the rocks

of the ocean basin note that it's been

trapped between the two continents

marking their original boundary these

two we see in mountain belts it's very

difficult to understand the deep

structure of a mountain belt by direct

observation the sand model allows us to

compress time and space and simulates

the internal structure of mountains