Looking for a term of art about eroded fossils

Is there a term of art to describe fossils that are degraded, infilled with later material, invaded by roots, etc.? ‘Reworked’ seems to imply that a fossil has been re-embedded in younger strata, but what of a fossil that’s found in the dirt and packed full of mud and bugs? The opposite of pristine, where it’s in a nice rock matrix. ‘Eroded’ might work, but I feel like there’s a better term.

“Weathered” would probably fit the bill and covers mechanical/chemical/biological agents. “Reworked” sounds accurate though and dirt is a younger stratum. “exhumed” might work too

‘Degraded’ will also do it, and refers to the integrity of the fossil being less than ideal, with no implications about cause.

Yes, that is the definition of reworked. I don’t believe there is a term for a fossil that is full of dirt other than “dirty”.

I think I’ll go with ‘weathered’, although ‘contaminated’ or ‘compromised’ might work as well in the scenario of looking for original biomolecules


bioclaustration! New to me!

“Weathered” means eroded. If it washes off without leaving behind damage, that isn’t weathering.

Well, in this case it is friable and fractured, invaded by roots and mud and nematodes.

I fed your exact question into ChatGPT and I didn’t trust most of what it said enough to repost here, but it did teach me a new term in part of its output:

Another term that is also used is “Bioturbated” which means fossils that have been altered by the movement of organisms in the sediment.

We use bioturbation a lot as a term in archaeology, and it can refer to something, like a wombat or rabbit digging up an object so its no longer in a stratified context, or tree roots shifting an artefact up or down in the strata to give a false earlier or later date or is simply rearranged, like the arrangement of bones in an articulated skeleton getting all mangled up. It does not necessarily mean or get used to describe damage to the artefact / fossil itself.

To really cover:

that’s why ‘degraded’ is appropriate, and is often used in palaeontological literature because it actually refers to impact on the the condition of the fossil and also it integrity within a depositional context. At a stretch ‘taphonomy’ or ‘taphonomic processes’ would also be a general term, but so broad as to be meaningless without further explanation.

In arts like clothing, furniture, paintings, all the objects a second hand dealer, antique dealer, would sell, degraded work is called “distressed”.

I like the application to a fossil - the term could also apply to a life form… so it begs the question of whether it became distressed when it was alive , or when ?

complicated patterns created by wear and aging, such as the parallel cracks and corrugation in leather, are called patina.

Geologists usually use “bioturbation” when talking about processes affecting sediments prior to lithification and so think of the process as being almost syndepositional. If geologists are your target audience, they would likely assume (on hearing “bioturbation” ) that the creature had been dismembered and moved by scavengers before fossilization took place

I’d say degraded is the actual term of art most used, based on a cursory literature review.

The only caveat is that fossils that are affected by post-extraction conditions (say, something from an anoxic depositional environment that’s now oxidizing in a museum case) are also called degraded.