Found in Limestone Canyon

[NatalieinFlagstaff]

Hello!  I am wondering about a couple of fossils found in Yavapai County, Arizona, approximately 30km south of Ashfork, Arizona.  I chose this canyon to explore because on another website I saw mention of Arthrodire plates having been found in a quarry here.  That site listed those plates being found in the Devonian Martin Formation.  Well, after some research I figured out that the quarry was associated with Drake Cement Plant, which is perched on the edge of a canyon called Limestone Canyon.  So off to the canyon my son and I went.  This canyon had several distinctly different limestone layers, but the deepest layer, exposed on the canyon floor, had a variety of these (most pics taken in the field). Most were in large slabs of rock, but we found a couple smaller pieces that we brought home.  We are dissolving one in Muriatic Acid out of curiosity, and it is revealing a "ring" of fossilized material.  Can anyone tell me what these are?  My son is quite curious to know.  Thank you for any help!

[NatalieinFlagstaff]

Here is the one we are dissolving...

[Pemphix]

 

I don't see a fossil here, but let's wait for other opinions...

[DPS Ammonite]

If it is the Martin Formation, there are two possibilities: a coral and a stromatoporoid. I do not see any fossils yet. Photos with close up details of any unusual organized textures in the fossils are needed. Can you take a photo (if you are using a phone) through a jeweler’s loupe or a magnifying glass? 

[NatalieinFlagstaff]

I was thinking that maybe they were trace fossils. Some sort of microbial mats or something. Most of those are still in the field. Here is one more picture I took while in the canyon. Tomorrow I will try to get a close up of the one currently bubbling in acid. 

[NatalieinFlagstaff]

We also found this incredibly delicate fossil and are wondering about its identity. It was about 2 inches long, and directly in line with it, about 18" away, was a second one about an inch long. I increased the contrast slightly to make it clearer. Thank you! 

[dhiggi]

14 minutes ago, NatalieinFlagstaff said:

We also found this incredibly delicate fossil and are wondering about its identity. It was about 2 inches long, and directly in line with it, about 18" away, was a second one about an inch long. I increased the contrast slightly to make it clearer. Thank you! 

Pretty sure that one’s a Rugose horn coral. Looks a lot like the ones we collect 

[NatalieinFlagstaff]

20 minutes ago, dhiggi said:

Pretty sure that one’s a Rugose horn coral. Looks a lot like the ones we collect 

Ah, I am new to this, and so I must train my eye. I found this 3 dimensional rugose horn coral a couple of weeks ago. But I never would have equated it with that delicate 2 dimensional fossil! Thank you dhiggi! 

[dhiggi]

3 minutes ago, NatalieinFlagstaff said:

Ah, I am new to this, and so I must train my eye. I found this 3 dimensional rugose horn coral a couple of weeks ago. But I never would have equated it with that delicate 2 dimensional fossil! Thank you dhiggi! 

It’s likely to be 3d through the matrix, with a cross section showing. That’s how we find them round here (UK)

[FossilNerd]

I agree with dhiggi on your second specimen. Looks like a longitudinal cross section of a solitary rugose coral. We are seeing the septa and dissepiment.

 

Not sure on the first one, but I would defer to DPS Ammonites expertise.
 

Cool pieces!  

[NatalieinFlagstaff]

3 hours ago, FossilNerd said:

I agree with dhiggi on your second specimen. Looks like a longitudinal cross section of a solitary rugose coral. We are seeing the septa and dissepiment.

 

Not sure on the first one, but I would defer to DPS Ammonites expertise.
 

Cool pieces!  

Thank you FossilNerd! I should learn my rugose coral anatomy, since that seems to be a common fossil where I am going

[NatalieinFlagstaff]

Ok, here are some more pics of those first...whatever they are. I cannot see any cellular structure. Anybody have any ideas as to a geological explanation? My 14 year old son, who rarely shows interest in anything other than his electronics, was really curious as to what this was. So I was hoping to keep his interest up

[DPS Ammonite]

Even though what you have cannot be identified as a fossil, they make neat sculptures with their rillenstein.
 

Photo from Stan Celestian.

 

https://www.flickr.com/photos/usageology/41259743951

 

 

[NatalieinFlagstaff]

3 minutes ago, DPS Ammonite said:

Even though what you have cannot be identified as a fossil, they make neat sculptures with their rillenstein.

 

 

Thank you DPS Ammonite! Part of what interested my son was the chemistry of revealing this formation. So we will continue to play with it

[DPS Ammonite]

5 minutes ago, NatalieinFlagstaff said:

Thank you DPS Ammonite! Part of what interested my son was the chemistry of revealing this formation. So we will continue to play with it

Here is what happens when you add HCl to limestone; you get calcium chloride (a salt used in pickles) carbon dioxide (the bubbles) and water. As a slight aside, if you do not soak the rocks long enough in fresh water after being in acid, you will see needle like crystals of CaCl2 growing. CaCl2 tastes salty.

 

CaCO3+2HCl→CaCl2+CO2+H2O

[FossilNerd]

2 hours ago, DPS Ammonite said:

CaCO3+2HCl→CaCl2+CO2+H2O

Ah stoichiometry! My high school sweetheart!