How do dinosaur fossils form? | Natural History Museum

millions of years ago this dinosaur was

going about his normal daily life but

his day went from good to bad really bad


after he died other dinosaurs eaten and

the rest of his skin and muscles rotted

away leaving just his bones

these were quickly buried by mud over

millions of years more layers landed on

top mud sand and even volcanic ash this

added up to a lot of weight on top of

the skeleton some parts got crushed the

layers of mud sand and ash turned into

hard sedimentary rocks while this was

happening water seeped into the bones it

left behind minerals turning the bones

to stone and creating a fossil earth

changed a lot over millions of years

rocks that were once deep underground

rose to the surface a process called

uplift very slowly wind water and ice

wore away the rock eventually bits of

the fossil skeleton were exposed and

became visible on the surface fossils

are constantly getting eroded out of

rock most are lost but if we're lucky

someone will find one nearly all of the

fossils we find around 99% are from

marine animals such as shellfish and


this is because they lived in the sea

for sand or mud could bury the remains

quickly after they died a dinosaur's

live on land so how do they get buried

so quickly most dinosaur fossils we find

belong to animals that were living near

to a lake or a river they died and a

short while later the area flooded

covering the remains in mud and silt

occasionally something more dramatic

happened in one example two dinosaurs

the Protoceratops and velociraptor

were fighting in the desert they were


when suddenly a sand dune collapsed on

top of them their fossils show them

frozen in there fighting poses in

another tragic example the feathered

dinosaurs city party was sitting on its

nest of eggs when a sandstorm blew in

and covered it fossils like this from

animals that were alive when they were

buried are really rare it's not just all

that turn into fossils dinosaurs can

also leave behind footprints and

impressions of skin and feathers

so next time you're near some sandstone

or mud stone think of what fossils could

be hiding just waiting to be discovered

it probably won't be a dinosaur fossil

as they're so rare but it could be

prehistoric sea creature like an

ammonite which went extinct at the same

time as dinosaurs many millions of years