Hidden Fossils?

[MinnMike]

I was wondering if there is a way to know if fossils are (hidden) in the rest of the rock, that are not exposed?

[Uncle Siphuncle]

Mike

In some cases with experience you can hidden fossils. Specifically, sometimes when splitting rock you can see fossils covered by a thin layer of matrix. They appear raised a bit above the plane of the rest of the slab and have the outline of the fossil. I've seen this presentation at times with Green River (Eocene) fish in fine grained limestone as well as with Archaeocidaris echinoids in Pennsylvanian shale as well as with certain crinoids in shale. These fossils are best prepped with microabrasives.

I do a little bulk sampling from time to time for micro shark teeth and micro echinoids. Seeing a concentration of small, desirable fossils on the surface is cause enough to fill a 5 gallon bucket if it breaks down and screens easily.

In general however, fossiling is a game of "what you see is what you get". When someone invents a "mammoth detector" I'll be the first in line to buy one.

[Desmond]

95% of the time it's what you see is what you get, beyond what you prep out of the rock.

But for what's hidden within there are only a few ways I know to see.

1. Acid bath prep (be sure to use a light mixture of vinager and water it takes FOREVER and some stone is more reisistant that a possible fossil inside)

2. Split it, look for a shape and remember you may have split through the center of it so look for outlines.

3. In a VERY few cases the fossil may have a higher or lower density than the stone by a sufficient amout to measure. This is a lot more work than it sounds like and I do not reccomend it. I was experimenting with the same question you posed. I could identify weather a piece of sylvania shale had a significant amount of fossils in it about 80% of the time. I only worked with pieces up to 1lb or so and each piece took about 2 hours to check mathimaticaly. Eventualy I figured out a simple dremel engraver was a LOT faster hehe.

So far as I know that's the only ways to "see" inside

[Desmond]

Mike

In some cases with experience you can hidden fossils. Specifically, sometimes when splitting rock you can see fossils covered by a thin layer of matrix. They appear raised a bit above the plane of the rest of the slab and have the outline of the fossil. I've seen this presentation at times with Green River (Eocene) fish in fine grained limestone as well as with Archaeocidaris echinoids in Pennsylvanian shale as well as with certain crinoids in shale. These fossils are best prepped with microabrasives.

I do a little bulk sampling from time to time for micro shark teeth and micro echinoids. Seeing a concentration of small, desirable fossils on the surface is cause enough to fill a 5 gallon bucket if it breaks down and screens easily.

In general however, fossiling is a game of "what you see is what you get". When someone invents a "mammoth detector" I'll be the first in line to buy one.

Hey have you tried taking a gallon milk jug cut the top to an opening about 3-4" across, add a few inches of sample dirt and use the hose w/o a nozle aimed about 30 deg down into the jug. It works great to wash out the residue while watering your garden. Your fossils and any gravel will stay in the jug and the soil will flow out with the water.

[DD1991]

On 11/6/2007 at 1:01 PM, MinnMike said:

I was wondering if there is a way to know if fossils are (hidden) in the rest of the rock, that are not exposed?

There is a technology called ground-penetrating radar, which uses radar waves to track fossils underneath the earth's surface. It was used in the 1990s to find the nodosaurid Animantarx (see Jones and Burge 1995).

 

Jones, R.D. & Burge, D.L. 1995. Radiological surveying as a method for mapping dinosaur bone sites. Journal of Vertebrate Paleontology 15: 38A.

[Mark Kmiecik]

On 11/6/2007 at 3:01 PM, MinnMike said:

I was wondering if there is a way to know if fossils are (hidden) in the rest of the rock, that are not exposed?

The simplest way to know is for me to tell you. Yes, there are fossils hidden in the rest of the rock. Everywhere, the whole world over.

[Joe_17]

why are ancient threads being resurrected ?

[DPS Ammonite]

6 minutes ago, Joe_17 said:

why are ancient threads being resurrected ?

Because at least one member is looking at our old content. Which is a good thing. Even if the original poster doesn’t reply, the conversation is moved forward.

[Randyw]

11 minutes ago, Joe_17 said:

why are ancient threads being resurrected ?

ain’t nothing wrong with that. It’s just new members going through Older posts and responding to them. I for one like to see the older posts from before my time coming up for me to read.

[LordTrilobite]

A lot of the times old links will be broken. Topics will often also be outdated due to new information. I'm not a fan of digging up old threads unless there is a good reason.

[Sjfriend]

Sometimes we get going flipping through the posts and don't always notice we gone back in time lol 

 

Plus with all this extra free time that we should be out in the field we have more time to dig up old post instead of old rocks

[EMP]

Yes there is a way depending on the preservation of the fossil. I know that x-rays have been used to find pyritized trilobites in the Beecher's Bed out in New York, and similar techniques could be used to identify  fossils in rock as long as the fossils are permineralized and there is sufficient density difference between the fossils and the host rock. 

 

Images taken of trilobites using x-ray: https://web.archive.org/web/20080706031322/http://www.amherst.edu/~jwhagadorn/research/beechers.html

 

Use of x-rays on fruits from the London Clay: https://www.nrcresearchpress.com/doi/pdf/10.1139/cjb-2016-0078

 

Use of x-rays on pyritized graptolites from the UK: https://pygs.lyellcollection.org/content/58/2/129