When you learn about fossils , you commence seeing dates thrown about like “ 265 million class former ” and “ dating back to the Jurassic ” like it ’s no self-aggrandising deal . Fossils can be incredibly , inconceivably old , but how do they survive so long while animal bones decay in just a few years ?
It all comes down to the conditions in which an brute die , and what happen to their corpse after they ’d kicked the bucket . IFLScience get to see first - hand the fossilise ivory of agiant sea monsterthat was chomping thing in one-half 150 million year ago . Asfossil expert Steve Etches MBEtold IFLScience , part of the reasonableness the pliosaur – an ancient shipboard soldier reptile – was maintain so well was because it roll in death , preserving its smile as it lie in face - down in the mud .
“ It ’s good that it was upside - down because actually , this is the adept side , ” said Etches . “ When you discover a dodo in a ledge or whatever , we always bend them upside - down because when it dies , the bit that goes down in the mud is undisturbed . It ’s always the top side that starts to take down more rapidly . "
A specimen ofMicroraptor guiwith bones and feathers, on display at the Paleozoological Museum of China.Image credit: Captmondo, own work, copyrighted free use, viaWikimedia
voiced tissues typically rot fairly quickly , though we do incur rarefied examples of preserved bite of peel ( even if some of them turn out to beforgeries ) . As for what keeps those bones ostensibly so intact for millions of age , it all comes down to fossilization .
What is fossilization?
fossilisation can take many forms , but the good fogy are typically form when the animal is promptly case in deposit – like our upside - down giant sea monster – which can be in the conformation of clay or volcanic ash tree . As this sediment builds up it becomes lithified , meaning it turns to rock , lock away the animal in place .
Permineralization is the most vulgar type of fossilization that happen when water from the ground , lakes , or ocean carries mineral into constituent tissues . Eventually , enough sedimentation are built up to create a kind of internal shape , which can be made of calcite , iron , or – as in the case of this staggeringly beautifulopalized plesiosaur – silica .
The mineral exchange the organic material within the os , like collagen and other proteins , until the fossil contain more mineral crystallization than the original pearl . Those calcareous ammonite you encounter along the fossil hunter ’s seaport that is theJurassic Coasthave been occupy in with calcite , while the astonishingfool ’s goldexamples are made up of pyrite .
If you want a fun way to demonstrate how mineral can create an inner casting to keen young scientists , theNational Park Servicehas a majuscule practice you could try produce home casts of sponger using salinity water .
Are all fossils bones?
No . A fossil can be any trace or stiff of retiring aliveness , be that a step , burrow , a bit of pelt , or a ivory . As theAustralian Museumexplains , the word fogy is taken from the Latin wordfossilis , which just mean “ dug up " , it ’s not specific to bone .
Do animal bones decay?
A small something call the decomposition ecosystem makes fast work of brute remains scupper to the elements , somethingDr Devin Finaughtytold IFLScience all about during his talk at CURIOUS Live in 2023 . “ Decompositionis technically delineate as the consumption of organic cloth by other organism , [ and is ] decided from strong-arm degradation of organic cadaver by physical , erosive forces , like water . The putrefaction ecosystem pivots around the dead body as a imagination and that ’s mainly for food , but many organism will also utilise it as a bringing up earth as a nursery , and as a tax shelter . ”
Once the decomposition ecosystem has had its fill , all that ’s typically depart behind is bone , and we can learn a surprising amount fromskeletal remainsthat linger on longer than your typical corpse . They wo n’t remain perpetually , however , as even animal bone finally decay . It can take several old age , but the delicious collagen found in bones is a food for thought source forbacteria and fungithat will deplete away at it until the stay on eventually crumble .
So , if you want to stick around as a fogy for the next few hundred million twelvemonth , it ’s time to write up very elaborated burial wishes .
