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Tube Structures--What are they?


allquieton

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Found near the Whetstone Mountains, near Tucson, Arizona.

 

I am very curious about the long, orange tube structures I found. Some folks told me they are just chert nodules. Others seem to think could be fossils. So, I took more photos to see if I can get more information on them.

 

They were found right near some other fossils--fenestellid bryozoans, rhynchonellid brachiopods, gastropods. The area is littered with fossils.

Several of these structures reveal a tube structure, which I think would be unusual in geology.

 

A lot of these structures have a very similar shape. Many of the tube walls seem to have a similar and uniform thickness.

 

Most are about as thick as a finger or thumb and range from 4 to 18 inches long. They could be much longer but there's no way to tell as they are broken at the ends. There are dozens of them in the area.

 

I really have no expertise and I sure don’t mind anyone telling me I’m wrong. But I wanted to give you an idea of my thinking. Please let me know what you think--thanks.

 

#1 shows a typical one

#2,3,4 show the far ends of #1

#5 shows another one with a hollow tube structure

#6 and 7 show two other structures

# 8 shows a far end of #1

#9 shows another structure end

#10 shows two that seem to be crossing each other

 

 

1050957210_wholefossil.jpg

235139665_starfarend.jpg

740553444_rightend.jpg

star.jpg

1816436003_hollow2.jpg

748089838_long3.jpg

long.jpg

piece.jpg

2046163488_end4.jpg

crossing.jpg

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What formation are they from? Horquilla, Escabrosa? The other fossils present might help.

 

They are definitely chert based on their relief from the limestone. They probably not body fossils unless you can see spicules in them in which case they are sponges. Do you see a mesh network that suggests that these are sponges? Near microscopic pictures would be needed to determine that these are sponges; I can’t see anything that suggests that a sponge is likely. 
 

If you see the same grains and fossils both in the chert and the limestone matrix then these are not body fossils. For example, if you see oolites, crinoid disks, shell fragments inside the chert and in the surrounding limestone then you are looking at chert that has replaced the limestone. The tubes then might be where the chert replaced the limestone along trace fossil burrows.

 

I found similar looking structures in the Escbrosa Limestone near Superior. Oolites are visible in the chert and the limestone; not a sponge or body fossil. Maybe a burrow.

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Thanks so much for the thoughtful response.

 

I don't know the formation, but I will try google to see if I can come up with it.

 

I don't see any kind of mesh network. There are no fossils in the chert that I could tell.

 

Could a burrow end up fossilized as tube shape then? I can't think of how you would get the tube structure without something tube shaped--but I'm sure there are many geologic processes that I'm just unaware of.

 

Here are some of the other fossils I found there:

 

 

454159492_1.jpg

coral.jpg

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I would guess Escabrosa just based on how the rock looks and the fossils types. But I really don't know for sure.

 

I did come across one fossil picture that looked somewhat similar at least in shape. It was identified on the webpage as coral from the phylum Cnidaria. It was from the Escabrosa formation. I can't tell the size. But this one is obviously a fossil where mine are not:

 

 

coral5310small.jpg

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