Igneous Fossil?

[painshill]

Igneous fossils? Yes… I know! Bear with me here.

Welcome anyone’s views on this item. It belongs to a friend of mine and she’s in the States, so I haven’t been able to personally examine it (I’m in the UK). She thought might be a trilobite.

Apart from the odd shape, I see heat shrinkage cracks, black glassy or crystalline material in the cracks and the typical colours of basalt weathering. So, my initial reaction was that its basaltic lava… probably pillow lava from rapid cooling as a result of molten rock meeting water. Igneous tells me it can't be a fossil so it has to be just an odd, weathered shape. The pseudo-fossil form seems to be actually a continuous part of the rock itself.

This was from the Licking River region of Ohio, where my friend is finding other pseudo-fossil shapes of highly weathered basalts, but nothing quite as weird as this. Also fossilised corals (in limestone) from the Lower Devonian or Silurian.

Fossils as we know them don’t generally occur in igneous rocks, apart from occasionally in volcanic tuffs… like the late Miocene petrified trees from the Yakima basalts of Southern Washington. But volcanic tuff is more or less sedimentary.

It occurred to me later that there are exceptions. Igneous fossils of sorts… or moulds and casts at least... can arise from molten lava meeting something organic. Like those found in Hawaii (and also the Galapagos):

http://lovingthebigisland.wordpress.com/2009/08/24/hawaiis-amazing-lava-fossils/

Fish cast in basaltic lava from Hawaii:

Penguin & seal pups enrobed in basaltic lava from St. Barthalome Island, Galapagos:

These are all recent… within the last 2,000 years and sometimes within the last 10 years… but surely there is no reason why ancient examples could not also exist?

Most of Ohio's basalt is from the Middle Run Formation and truly ancient (ie pre anything that could be organic), but there have been volcanic intrusions in the Ordovician and again in the Devonian.

So, is this just a very odd pseudo-fossil or could it conceivably be an organic cast? The morphology looks wrong for trilobite, but is there anything else that it could be?

Roger

[Kosmoceras]

Hello there, I would not want to dissiapoint you, but I do not think that this is a fossil. It looks more like where lava has come out of a volcano. It has dried, and then more has come over the top. Thats what I think. But do not take my word on it, I am no expert in Igneous rocks.

Best wishes,

Thomas.

[painshill]

Hello there, I would not want to dissiapoint you, but I do not think that this is a fossil. It looks more like where lava has come out of a volcano. It has dried, and then more has come over the top. Thats what I think. But do not take my word on it, I am no expert in Igneous rocks.

Best wishes,

Thomas.

Thanks Odin. Yes, I know it's lava... or at least that's where my money was. The questions really were: does anyone have knowledge of organic casts in lava that are older than the recent ones from places like Hawaii and the Galapagos? I guess you could include Pompeii and Herculaneum in that list as well. And does the shape remind anyone of anything that might once have been organic? It's the oddest-shaped lump I have ever seen, it does have a modicum of bilateral symmetry and some apparent 'features' for want of a better word.

There's no 'disappointment' factor here. As I said, I thought it was basaltic lava but was just musing retrospectively on the possibility of it being a cast of something the lava had enrobed and incinerated.

Roger

[bdevey]

Hi painshill, I don't think she has a fossil there. Igneous fossils appear as molds, while the closest thing that resembles, is a burrow cast, but the surface is clearly air or water cooled.

Do you have a link to the photo examples you posted? Id like to ckeck those out. thanks

Bob

Tff Igneous fossils link

.

Edited November 23, 2011 by bdevey

[painshill]

Hi painshill, I don't think she has a fossil there. Igneous fossils appear as molds, while the closest thing that resembles, is a burrow cast, but the surface is clearly air or water cooled.

Do you have a link to the photo examples you posted? Id like to ckeck those out. thanks

Bob

Tff Igneous fossils link

.

Thanks for your link... very interesting. I didn't think to search the forum before I posted.

Unfortunately, I didn't keep the links to where those two pics came from. If I recall correctly, they were isolated pics being used as funky examples of what nature creates on sites that were not strictly fossil-related. Travel & adventure blogs or something of that kind. If there had been any significant learning I'm sure I would have kept the links.

Roger

[Auspex]

...they were isolated pics being used as funky examples of what nature creates on sites that were not strictly fossil-related...

I'm certain that the purported "penguin & seal pups enrobed in basaltic lava" is just a suggestive form that the lava took. A penguin in lava would be a cavity containing maybe charred bone fragments.

[bdevey]

Thanks for your link... very interesting. I didn't think to search the forum before I posted.

Unfortunately, I didn't keep the links to where those two pics came from. If I recall correctly, they were isolated pics being used as funky examples of what nature creates on sites that were not strictly fossil-related. Travel & adventure blogs or something of that kind. If there had been any significant learning I'm sure I would have kept the links.

Roger

Roger,

Thanks for the reply back, thats what I was thinking, they are photos of what someone thought they saw. I agree with auspex, they would be like the Rhino, in the link I gave. A mold with or without bones,

I think some people get confused when they see photos of the victims of Pompeii. They see what looks like a person made of volcanic ash/lava, when in reality, there was a void were a person was(a mold), filled in with plaster to make a cast of the person.

They are so freaky to look at. :startle:

Bob

[Missourian]

Considering that there has been much heavy industry in that region, it's possible that the basaltic-looking stuff could be slag.

Who knows.... The trilobite-like thing could be an actual fossil thrown into the mix.

[Wrangellian]

It sure does look like slag, I've got the exact same stuff from an old smelter in my hometown. If taking pics werent such a pain I'd show you an example...

[Hannah]

<p>It looks a lot like slag from the old steel mills or glass works factories. We find that stuff up here in Illinois all the time.</p>

[stricklandhighland]

If this is also the same ignious please do tell

[Fossildude19]

No, this looks like limestone.

[Kiros]

there is a very incredible case, found in Italy near Rome, of a 30000 old Gyps fulvus cast made by a pyroclastic flux.

Edited September 13, 2022 by Kiros

[Styles]

50 minutes ago, Kiros said:

there is a very incredible case, found in Italy near Rome, of a 30000 old Gyps fulvus cast made by a pyroclastic flux.

 

 

Awful demise