What causes this? Sand "sculpture" found on Mississippi River.

[Harry Pristis]

12 hours ago, Tidgy's Dad said:

No. You are attacking a straw man. 

Please read my earlier post on the matter. It was just a comparable example of how rare fulgurites are away from deserts and wide beaches. Can you provide examples / photos / articles of fulgurites from the Mississippi River Flood Plain in Missouri, please? 

 

Here ya' go:

 

[JohnJ]

On 10/11/2021 at 6:26 PM, Raistlin said:

Some good opinions so far.

Some additional information. Looking under a scope they appear bonded. No sign of melting but bits shaped well to each other like really molded/bonded together. 

 

You can rub some sand off but not all. It's like a puzzle put together. Only the loose sand comes off.

 

It absorbed paleobond like dry wood does water.

 

All the legitimate images of sandy fulgurites I can find online show areas of melted fusion.  Robert's description and images of broken areas are very typical of rhizoliths.

 

Clear images of a larger broken section could provide more insight.

[Raistlin]

Sorry I've been absent while most of you continue to debate this "whatever it is". I'm on nights right now but I can try again to get some different photos this weekend. For now I did do an acid test using hydrochloric acid. There was no fizz not even a bubble. The acid was simply absorbed just as water would be. You can see that it was wet at best.

 

The idea of rhizolith seems possible too. I will deliver more photos later but for now the acid test was the quickest thing I could do. 

[Tidgy's Dad]

17 minutes ago, Raistlin said:

Sorry I've been absent while most of you continue to debate this "whatever it is". I'm on nights right now but I can try again to get some different photos this weekend. For now I did do an acid test using hydrochloric acid. There was no fizz not even a bubble. The acid was simply absorbed just as water would be. You can see that it was wet at best.

 

The idea of rhizolith seems possible too. I will deliver more photos later but for now the acid test was the quickest thing I could do. 

Very interesting. 

The lack of fizzing would seem to rule out calcite, but the fact that liquids are absorbed suggests it isn't 'glass' either.  

Perhaps a rhizolith composed of other minerals? 

[FranzBernhard]

7 hours ago, Raistlin said:

For now I did do an acid test using hydrochloric acid.

 

7 hours ago, Raistlin said:

The idea of rhizolith seems possible too.

 

7 hours ago, Tidgy's Dad said:

Very interesting. 

Indeed!

You are in need to test your acid .

 

7 hours ago, Tidgy's Dad said:

but the fact that liquids are absorbed suggests it isn't 'glass' either.

Some interconnected porosity might still be present?

Highly interesting things!

 

Franz Bernhard

[FranzBernhard]

9 hours ago, Harry Pristis said:

Here ya' go:

What are these? Root fulgurites?
Franz Bernhard

[JohnJ]

On 10/11/2021 at 3:07 PM, Raistlin said:

As the title says. Found along the Mississippi River on a sand/gravel bar. I've found them before. They are hard but can be broken. 

 

 

1 hour ago, FranzBernhard said:

What are these? Root fulgurites?
Franz Bernhard

 

They are the OP's specimens Harry asserts are fulgurites. 

[doushantuo]

Edit: text added

Not saying it is one, of course ...

 

At least some of its morphology shows a slight resemblance to the posters objects.

Got the idea for this from LAETOLICHNUS:

[Raistlin]

I'm doing the best I can to get better shots. It's really hard to get a photo of what I see in person though. 

 

This is the last piece (not pictured before) but it also fits with the sand/silt/mud mixture I see along the Mississippi River. You really aren't going to get a "pure" sand you would in a desert or normal beach. I think fulgurites (if that's what these are) would have impurities not found in most places. Anyway this piece is stained a rusty color with thongs I see it could be caused by several things.

 

In the photos I'm trying to point to what I see as solid with some chunks mixed in (stuff not like the typical sand).

 

I won't be breaking the two largest pieces because due to breaking one before I wanted to make them more stable and used paleobond on them which can be seen under a scope as it doesn't absorb as deeply as the nake eye makes it seem.

 

As these are the only four samples of this I have after years of walking the river I'm trying to cause them as little damage as possible. At most I am willing to cut the straighter end off of the lighter colored un-paleobonded piece.

 

 

[Raistlin]

Massively important note, new discovery.

 

It seems I've made a huge error. I'm sorry as I had no idea. But I also learned a lesson so I've got that going for me.

 

It seems the small bottle of HCl i was using has lost its potency. I decided what the heck lets see if this newer acid gets a result. Boy did it. Massive fizz. The small piece is still breaking down I'll give photos of what's left when it stops fuzziness. By my estimate it has lost about half its size. I didn't measure before because I didn't think this would happen.

[Raistlin]

Nothing left to take a photo of but grains of sand.

[DPS Ammonite]

2 minutes ago, Raistlin said:

Massively important note, new discovery.

 

It seems I've made a huge error. I'm sorry as I had no idea. But I also learned a lesson so I've got that going for me.

 

It seems the small bottle of HCl i was using has lost its potency. I decided what the heck lets see if this newer acid gets a result. Boy did it. Massive fizz. The small piece is still breaking down I'll give photos of what's left when it stops fuzziness. By my estimate it has lost about half its size. I didn't measure before because I didn't think this would happen.

Now your pictures and acid reaction make sense; a rhizolith it is.

[Raistlin]

 

24 minutes ago, DPS Ammonite said:

Now your pictures and acid reaction make sense; a rhizolith it is.

 

It was difficult to get to this point. I'm fine with it being what ever is decided I just want to know what that is. Looking at it I was thinking I was seeing grains fused together it seems I was terribly wrong. And I learned that the little dropper bottle of HCl (mixed with distilled water) that is from an old chemistry set had lost it's potency. Luckily I bought a larger bottle last year. Now I just need to get it into the sealed dropper bottle (it's designed to be tossed when empty and the dropper cap was sealed into the bottle. I might have to buy more bottles and fill them.  

[JohnJ]

2 hours ago, Raistlin said:

 

It was difficult to get to this point. I'm fine with it being what ever is decided I just want to know what that is. Looking at it I was thinking I was seeing grains fused together it seems I was terribly wrong.

 

Great follow up, Robert.  This topic makes me want to find a fulgurite, now.  

[doushantuo]

You did something priceless: you engendered reasoned debate here

It looks liike you are attempting some detailed petrography?

Edited October 16, 2021 by doushantuo

[minnbuckeye]

I am so glad you presented your find. It was an educational process watching many great minds decipher your find.  

 

 Mike

[Troodon]

Very educational topic, way to go.  thanks everyone

[Tidgy's Dad]

10 hours ago, JohnJ said:

 

Great follow up, Robert.  This topic makes me want to find a fulgurite, now.  

Maybe come to Morocco! 

In the areas around the ergs, areas of dunes where they reach a height of 150 metres, fulgurites seem to be fairly common. These regions aren't true Sahara, but part of the pre-Saharan steppes in the shadow of the Atlas mountains.

Erg Chebbi (there are others)

  

There are a lot of storms in the mountains and they move over the hamada and dunes. Lightning strikes the tops of the dunes quite frequently, perfect conditions for fulgurite formation. 

The locals don't go out with spades to dig them up, they just wait. The ever changing, rolling desert landscape will reveal the fulgurites just sticking out of the sand ; 

I think this photo is set-up, but it does happen naturally, I understand.

The local villages like Merzouga have little shops and they will often have boxes of fulgurites for sale. I've seen many but never found or bought any, next time I'm down there, I'll try and acquire some, do some tests and show them on the forum. 

[fossilnut]

Earlier today I encountered the word erg so your post was very interesting. The erg was the Navajo Sandstone in Capital Reef National Park in the USA. Surprisingly, very large 5 foot high stromatolites were found in this erg formation. Apparently, rivers and lakes retained water for a considerable time period in this extensive desert.

BTW I found a small fulgurite at the water line in North Myrtle Beach, South Carolina a few years ago.

Edited October 16, 2021 by fossilnut

[Raistlin]

9 hours ago, doushantuo said:

You did something priceless: you engendered reasoned debate here

It looks liike you are attempting some detailed petrography?

 

I'm just a guy trying to learn about the world I live in. I only wish that was my job instead of just hobby.

[Auspex]

5-Star topic! There is a kind of magic that distinguishes the best of the 'free-range' thinking on TFF, and this is a great example!

[doushantuo]

My latest feeling :this might be a maize rhizolith