YouTube,itsCram.HowdoFossilsform?They'renotjustbonesthatendupundergroundwaitingtobedugout.ThewordfossilitselfcomesfromtheClassicalLatinwordFossilis,whichmeansobtainedbydigging.Butasweknowsomefossilscanbeobtainedwithoutdigging.Thereare4typesoffossils,mold,cast,traceandtrueformfossils.Moldfossilsareimpressions,withoutthebonesthemselves.Castfossilsarebasicallymoldfossilsbutarefilledin,typicallywithminerals.Tracefossilsaretracesoftheexistenceofthecreature,suchasnests,burrowsortracks.Trueformfossilsactuallyhavepartsoftheanimal,typicallybones.Therearemanytypesoftrueformfossilization,buttwomainkindsareunalteredpreservationandpermineralization,whichiswhatwewillbefocusingontoday.Unalteredpreservationismostcommonininsectsandothersmallcreatures.Itiswhentheyaretrappedinathicksubstancewhichhardens,preservingallpartsoftheirbody.Thissubstanceistypicallyamber,whichishardenedtreesap.permineralizationiswhenrocklikemineralsseepintotheanimalandreplaceitsorganictissueandsometimesbone.Thisiswhyfossilizedanimalsseemtohavedensebones,itisbecauseofthemineralsthatseepedin.Onewaythiscanhappenisinabodyofwater.Theanimalwillsettleatthebottom,andthedecompositionprocesswillbegreatlyslowedbythesurroundingwater.Eventuallysedimentwillcoverthebody,andmoreandmorelayersofrockwillcoveritontop.Thispressurewillcausepermineralization.Eventually,duetogeologicforces,thefossilsmaybeclosertothesurfaceorevenabovegroundwhichiswherewecandiscoverthem.Thoughnowwithouttechnologyandourknowledgeofmigrationpatternsandhabitatswecanaccuratelypredictandfindfossilsunderground,inthepastwehadtorelyonchancetostumbleuponsomethinggreat.IhopeyouenjoyedthisvideoasmuchasIappreciatedyouwatching.Subscribetostayuptodateonallmylatestsciencevideos,anduntilnexttime,Cramout.YouTube,itsCram.HowdoFossilsform?They'renotjustbonesthatendupundergroundwaitingx1.0x0.5x0.75x1.0x1.5影片重複字級大小快速鍵返回175%150%125%100%90%字幕與單字影片操作你可以在這邊進行「影片」的調整，以及「字幕」的顯示BackNextB1中級美國腔化石是如何形成的？(HowdoFossilsForm?)14115羅紹桀發佈於2021年01月14日更多分享分享收藏回報影片單字