Oncolites? Something else? Location?

[Wrangellian]

I acquired these two slices of something from a rockhound couple in our club. They could not remember what they are or where they came from, but they could be from Arizona or somewhere in the Southwest US as they spend their winters in Arizona and always come back with stuff from collecting and wheeling and dealing down there.

The bigger piece especially looks like oncolites to me, but I have been fooled before. Does anyone recognize either of these, and more importantly where they might be from? (If I can figure out the location I'll have a better chance of tracking down the ID/age.)

Both pieces came already polished on one side. Smaller one has scratches. I tested both with vinegar and the larger one fizzes. (It would not fizz on the polished surface, but on the rough edge it did). The smaller one did not noticeably fizz. I thought it looked fossily but obviously different from the bigger one, so it might have been from a different chunk from the same site or it may be completely unrelated. Maybe not even sedimentary. The little 'bits' in the smaller piece seem to have crystalline interiors but surrounded in the same type of reddish 'buildup' that the oncolites(?) in the larger piece have.

I'm not really expecting a decisive answer (I've not been too lucky in getting mystery items confidently ID'd lately, from the forum or otherwise... I seem to have a knack for digging up strange things). But I thought I would survey the forum in the off-chance someone recognizes the material.    A Google image search did not turn up a perfect match for either.

The color balance in my photos may be a bit off (indoor lighting), but it's the best I could do for now. I could try direct sunlight tomorrow.

 

Side-by-side comparison of both pieces:

 

Weathered edges (smaller piece on top) - the greyish patches could be either paint or rock saw sludge, it won't come off easily:

Edited May 30, 2023 by Wrangellian

[Wrangellian]

I'm leaving the photos large so as to show as much detail as possible. Last 3 taken with macro lens.

 

The bigger piece:

Note the grey 2x2cm scale at bottom. All the 'blobs' are under 1cm in size.

 

 

 

 

[Wrangellian]

The smaller piece:

 

 

 

[Wrangellian]

For compare/contrast, here's my slice (wet, in outdoor light) of the oncolite material from the Bristlecone Pine reserve in the Sierras. I don't think the above pieces are from there. The oncolites here are generally larger, some close to 1cm, and of course the color is quite different. (Length pf slice >16cm)

 

Edited May 30, 2023 by Wrangellian

[rocket]

no idea that makes sense, first one reminds me to my last pizza 

[FranzBernhard]

4 minutes ago, rocket said:

First one reminds me to my last pizza

Ouch!!

 

Seriously, also no serious idea!

@doushantuo, @DPS Ammonite, thanks!

Franz Bernhard

[Yoda]

@Wrangellian

Interesting.

 

The bigger piece does remind me of an Oncolite. 

Not too sure about the smaller one. 

 

@MarcoSr  ?

[doushantuo]

oncolitic packstone,with miscellaneous bioclasts.

the oncolites look like they may be the "cyanoliths"* auct.(having an algal origin)

* a term you don'tcome across much anymore

And ,if i may say so : it could function as a "type facies depiction",it's that classical

Nice one,Wrangellian!Beautiful piece,in my book a piece to treasure

last piece might be chamositic ooids,judging from petrography alone

ooidal ironstones have a tendency to occur in Ordovician strata,BTW

 

 

edit,post FranzBernard reaction: i'll let the "packstone" stand(bindstone?/bafflestone?) 

Edited May 31, 2023 by doushantuo

[DPS Ammonite]

I have not seen anything like either one from Arizona. Maybe a lapidary expert from the SW US would have a better idea.

[doushantuo]

smaller piece reminded me of Tubiphytes Maslov

edit:

smaller piece has bits reminded me of Tubiphytes Maslov

 

edit: the "smaller piece" looks like a piece of Phylloid(algal) carbonate,maybe with Palaeoaplysina bits and poorly preserved fusuline forams.as can be found in,eg.the Wolfcampian of Texas or Axel Heiberg Island,

arrows pointing to thin yellow lines: algal cortex

 

Edited May 31, 2023 by doushantuo

[Wrangellian]

13 hours ago, rocket said:

no idea that makes sense, first one reminds me to my last pizza 

 

13 hours ago, FranzBernhard said:

Ouch!!

Seriously, also no serious idea!

@doushantuo, @DPS Ammonite, thanks!

Franz Bernhard

I guess it could either stimulate or ruin one's appetite, depending on your first impression. I does kind of look like cheese and very tiny bits of pepperoni!

[Wrangellian]

8 hours ago, DPS Ammonite said:

I have not seen anything like either one from Arizona. Maybe a lapidary expert from the SW US would have a better idea.

Thanks, the trouble is finding the right one to ask. The people in my club are useless - the best ones to ask were the ones I got it from, and they had no idea. Stuff does get around the lapidary community through trading, but the info too often disappears along the way.

[doushantuo]

You might approach Salvatore Mazzullo with your finds.

[Wrangellian]

43 minutes ago, doushantuo said:

smaller piece reminded me of Tubiphytes Maslov

edit: the "smaller piece" looks like a piece of Phylloid(algal) carbonate,maybe with Palaeoaplysina bits and poorly preserved fusuline forams.as can be found in,eg.the Wolfcampian of Texas or Axel Heiberg Island,

Thanks much.. I would guess the Texas Wolfcampian would be more likely than Axel Heiberg Island! I'll look into those names/terms.

Cyanoliths seems like a good umbrella term for stromatilites/oncolites/thrombolites... It may not be used much anymore but I might start using it myself!

[doushantuo]

BTW: great photography,spot on.

Here's the thing: good photography makes you take a far deeper interest in what's being shown,than would be the case with blurry badly lighted pictures.

Edited May 31, 2023 by doushantuo

[Wrangellian]

1 hour ago, doushantuo said:

BTW: great photography,spot on.

Here's the thing: good photography makes you take a far deeper interest in what's being shown,than would be the case with blurry badly lighted pictures.

Agreed... I try to take good enough pics for people so people are able to tell what they're looking at, but it's not always easy. Next perhaps I should look into getting microphotos of some of these things - not sure it would help with these pieces, but it might.

[Wrangellian]

5 hours ago, doushantuo said:

smaller piece reminded me of Tubiphytes Maslov

edit:

smaller piece has bits reminded me of Tubiphytes Maslov

 

edit: the "smaller piece" looks like a piece of Phylloid(algal) carbonate,maybe with Palaeoaplysina bits and poorly preserved fusuline forams.as can be found in,eg.the Wolfcampian of Texas or Axel Heiberg Island,

arrows pointing to thin yellow lines: algal cortex

 

This one you were referring to as the smaller piece? This one is the larger... The smaller slice has the elongated bits. On the other hand, as Iook more closely at this one, I notice a few elongated crystalline bits inside those blobs, similar to those in the smaller slice, so maybe the two are related - maybe from different layers at the same location, or something like that. Just speculation of course.

[doushantuo]

the slightly more irregular,blobby pieces,and the ones that display rounded angles might be "Tubiphytes".

Current thinking: it is an (algal?) "consortium"

Paleontologically speaking,it can be thought of as an "incertae sedis",which makes nobody any wiser,but hey .. 

 

 

[Wrangellian]

21 hours ago, doushantuo said:

the slightly more irregular,blobby pieces,and the ones that display rounded angles might be "Tubiphytes".

Current thinking: it is an (algal?) "consortium"

Paleontologically speaking,it can be thought of as an "incertae sedis",which makes nobody any wiser,but hey ..

I'm finding it difficult to pin down Tubiphytes or find anything similar from the Texas Permian - not that I doubt that suggestion, just that it's hard to find any clear matches via Google.

[grandpa]

I did a search on Yahoo Search and on Google Scholar under "Tubiphytes Texas Permian" and a number of papers came up with each search.