Coprolite Questions

[DPS Ammonite]

I have yet to see any expected fossilized organic matter in any agatized dino dung masses that are sold by the hundreds. I agree that almost everything sold as fossilized dung contains no dung including these:

[Carboniferous320]

Hello,  this is my first post to the forum.  I read the heading concerning "coprolites questions".  Here is a link to an interesting article.  Could these be 'cololites'?

 

https://www.researchgate.net/publication/247855440_A_fresh_look_at_sideritic_coprolites

[Rockwood]

5 hours ago, Carboniferous320 said:

Could these be 'cololites'?

Proof for that would be sort of like adding a layer on top of the proof needed for it to be called a coprolite I would think. One would need to know the exact shape of the animals G.I. tract and/or explain the bias that failed to preserve the skeleton.

[Carl]

8 hours ago, Carboniferous320 said:

Hello,  this is my first post to the forum.  I read the heading concerning "coprolites questions".  Here is a link to an interesting article.  Could these be 'cololites'?

 

https://www.researchgate.net/publication/247855440_A_fresh_look_at_sideritic_coprolites

Seilacher was a true genius of ichnology, and his is the one voice for these things being bromalites (coprolites, cololites, etc.) that gives me pause. However, until they are more conclusively demonstrated to be such or well-explained as something else (the gas-extruded iron mud hypothesis lacks groundtruthing) I'll reserve my opinion.

[Auspex]

12 hours ago, Carboniferous320 said:

Here is a link to an interesting article. 

Welcome to the Forum!

Thanks for the link; I had not seen that before. It is an interesting proposal, but "prefossilized by bacterial activity and later transformed into siderite with no traces of original food particles left" is a statement fraught with startling concepts with no proven mechanisms. I am highly skeptical.

[Misha]

I cut open and sanded the "coprolite", there are absolutely no inclusions inside and it has a metallic sheen to it.

[ynot]

Looks like pyrite to Me.

[Rockwood]

Still, what's needed is a distinction between pyrite and pyritized.

[Carl]

On 5/15/2019 at 12:29 AM, Carboniferous320 said:

Hello,  this is my first post to the forum.  I read the heading concerning "coprolites questions".  Here is a link to an interesting article.  Could these be 'cololites'?

 

https://www.researchgate.net/publication/247855440_A_fresh_look_at_sideritic_coprolites

Pyrite would be more golden. This looks like straight iron. Very odd.

[Misha]

50 minutes ago, Carl said:

looks like straight iron.

I thought it did to, the material has no reaction to a magnet, not even the tiny particles left from sanding are attracted to it.

[ynot]

1 hour ago, Carl said:

Pyrite would be more golden. This looks like straight iron. Very odd.

Could be siderite or one of the other iron minerals.

 

54 minutes ago, Misha said:

, the material has no reaction to a magnet,

Most iron minerals are not magnetic. Only magnetite and some hematite are magnetic.

[Rockwood]

Tin will self destruct if stored improperly. Any chance that it could be involved ?

[ynot]

18 hours ago, Misha said:

I cut open and sanded the "coprolite", there are absolutely no inclusions inside and it has a metallic sheen to it.

In this picture I can see several cubic crystals. Most likely pyrite that has altered to another iron mineral as sulfur was replaced with oxygen or other elements.

[Carl]

On 5/15/2019 at 12:29 AM, Carboniferous320 said:

Hello,  this is my first post to the forum.  I read the heading concerning "coprolites questions".  Here is a link to an interesting article.  Could these be 'cololites'?

 

https://www.researchgate.net/publication/247855440_A_fresh_look_at_sideritic_coprolites

I don't think those are cubic crystals. They look more like dessication fractures. A bit like septarian cracks. Look at the original post.

[Misha]

48 minutes ago, Carl said:

I don't think those are cubic crystals. They look more like dessication fractures. A bit like septarian cracks. Look at the original post.

Yes, those are definitely fractures.

[ynot]

I agree that the piece has some cracking, a trait typical of altered pyrite. And the surface is mostly from breakage which is a rough uneven fracture, also a trait of iron minerals.

But - the only minerals I know of that will propagate a cubic fracture / dislocation crack are calcite and feldspar. And I definitely see several cubic features.

Since the piece is definitely not calcite or feldspar and does show other traits of an iron mineral, it is reasonable to assume it is an altered pyrite.

[Misha]

3 minutes ago, ynot said:

altered pyrite

Is there anything I can do to confirm this?

Chemical reactions with other compounds? Streak? Hardness?

[ynot]

46 minutes ago, Misha said:

Streak? Hardness?

These two would be a good start. You can also do a specific gravity test.

All should indicate an iron mineral. My guess is siderite.

 

For the first 2 tests make sure You are not using the oxidized surface (rusty looking crust.).

[Misha]

8 minutes ago, ynot said:

These two would be a good start. You can also do a specific gravity test.

All should indicate an iron mineral. My guess is siderite.

 

For these test make sure You are not using the oxidized surface (rusty looking crust.).

I will do these when I get home in a few hours.

[Mark Kmiecik]

So, is it a mineralized coprolite or just mineral?

[Misha]

3 minutes ago, Mark Kmiecik said:

So, is it a mineralized coprolite or just mineral?

Believe that it is just a concretion

[Mark Kmiecik]

5 minutes ago, Misha said:

Believe that it is just a concretion

That's the direction in which I was leaning. Thank you.

[Carboniferous320]

Is mineralized coprolite and/or cololoite completely out of the realm of possibilities?  If leaning towards concretion, how was it formed? 

[ynot]

13 minutes ago, Carboniferous320 said:

Is mineralized coprolite and/or cololoite completely out of the realm of possibilities? 

I think so.

 

13 minutes ago, Carboniferous320 said:

  If leaning towards concretion, how was it formed? 

Water seeping through the rock carrying iron or sulfur meets sulfur or iron in the rock and the two elements bond to form pyrite. This reaction will often form from/around a "seed" that was a biologic something but does not need a biologic starting point.

 

There are many different concretions of other mineral types, not all form the same way.

[Misha]

5 hours ago, ynot said:

These two would be a good start. You can also do a specific gravity test.

All should indicate an iron mineral. My guess is siderite.

 

For the first 2 tests make sure You are not using the oxidized surface (rusty looking crust.).

Hardness is around 4 scratches calcite easily but does not scratch apatite.

Streak is a rusty brownish orange.

Density somewhere around 3 grams per cubic centimeter.