One thing that still blows my mind about dinosaurs is the massive timeline. Relevant to this question are the time periods:

  • Triassic Period (252.17 to 201.3 million years ago)
  • Cretaceous Period (145 – 66 million years ago)

Triassic-period dinosaur fossils are 50+ million years older than Cretaceous-period dinosaur fossils. I would thus predict a massive difference in fossil quality. However, I'm unsure because perhaps any fossil that's able to last say 1 million years can just as easily last say 100 million years.

Question: Is there a massive drop in quality of Cretaceous vs. Triassic dinosaur fossils?

  • $\begingroup$ I think we'd have to know what "quality" means. Dinosaurs went through all of their evolution during the time span, and the world underwent huge changes. If you're interested, a standard text book would be "Benton, Vertebrate Palaeontology". I'm sure it can be found on Amazon and elsewhere. $\endgroup$
    – user20217
    Jul 22, 2020 at 21:22
  • 1
    $\begingroup$ This is going to be a very opinion based answer, there are hundreds of thousands of fossils across that span of time and no one has looked at all of them, "quality" is already an opinion laden word. $\endgroup$
    – John
    Jul 23, 2020 at 23:20

2 Answers 2


No, there is no massive difference in fossil quality due to the extra 200 million years or so that the oldest dinosaur fossils have spent in the ground compared to the most recent ones at the end of the Cretaceous. Once fossils are properly fossilised, they remain unchanged unless something happens to the rocks. This could be weathering, which damages or destroys many valuable fossils, including recent ones like hominids, or it could be metamorphism, which damages or destroys them with heat.

I have seen a photo of a one-billion-year-old fossil from the late Precambrian of a marine algae reliably dated by the new Rhenium 187 - Osmium 187 method, and it was in an excellent state of preservation. Likewise with fossils preserved in amber, some of which are tens of millions of years old but look as fresh as if they had only died yesterday.

  • $\begingroup$ I'm not sure what's wrong with this answer. Although this user often writes really bad answers, this one is pretty much correct. Upvoted. $\endgroup$
    – Gimelist
    Feb 24, 2020 at 2:33
  • $\begingroup$ For an example of amber fossilisation, see "What features facilitate amber fossilisation" a couple of questions further on. $\endgroup$ Feb 24, 2020 at 8:10
  • $\begingroup$ there is however a drop off in quantity, just due to having more chances to get damaged or destroyed. $\endgroup$
    – John
    Jul 23, 2020 at 3:42

This proably cannot be answered in a scientifically valid way at this time. There are hundreds of thousands of fossils across that span of time and no one has looked at all of them, "quality" is not something that is measured routinely. Worse there is a massive confounding factor, different formations have drastically different preservational quality. For instance the Solnhafen is a much earlier formation than the Lance formation but has drastically better preservation amd detail just becasue of the drastically different environments.

Even trying to study this question would be swamped with problems just due to how drastically different the quantity of fossils are from each time period. Quality for fossils is strongly influenced by the local formation conditions (chemistry, grain size, burial speed, ect.) so it may be nearly impossible to answer without doing a specific study( it would be very expensive study). I am aware of no such study ever having been done and I know of no generally recognized difference but this is just one paleontologists experience.


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