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March 23, 2020 Peace River Unknown (geologic?)


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Harry Pristis

The answer you got seems rather dismissive.  I just don't see how your objects shaped like cauliflower florets were produced by torpedo-shaped clams.  Are there ANY identifiable burrows, mold or cast, in the objects you collected?

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Plantguy

Hey John, sorry I missed the post earlier...they are interesting for sure! 

 

I am interested in what Roger is seeing/describing. Which items in the first photo did you send to Roger/did he actually see? Did you take a photo of just what got sent--just trying to understand the context. Thanks!

 

Regards, Chris 

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Sacha
14 hours ago, Harry Pristis said:

The answer you got seems rather dismissive.  I just don't see how your objects shaped like cauliflower florets were produced by torpedo-shaped clams.  Are there ANY identifiable burrows, mold or cast, in the objects you collected?

 

I'm going to clarify with him what he means. After thinking about it for a while, I imagined a surface similar to what Ken was proposing except not a dissolved surface, but one packed with small shallow clam holes that then got filled. These pieces would be the cast from that surface.

 

There are no identifiable "burrows" in any of the pieces I've found although I have 1 small piece where the "bumps" have a longer aspect ratio. I'l get a picture when the sun comes up. 

 

6 hours ago, Plantguy said:

Hey John, sorry I missed the post earlier...they are interesting for sure! 

 

I am interested in what Roger is seeing/describing. Which items in the first photo did you send to Roger/did he actually see? Did you take a photo of just what got sent--just trying to understand the context. Thanks!

 

Regards, Chris 

 

I didn't take a picture of the pieces I sent to Roger Chris, but they all look about the same except for the small piece I'm going to take a picture of this morning for Harry.

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Daniel Fischer

Looks kind of like gastropods to me, but I don't really know.

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Plantguy
Posted (edited)
1 hour ago, Sacha said:

 

I'm going to clarify with him what he means. After thinking about it for a while, I imagined a surface similar to what Ken was proposing except not a dissolved surface, but one packed with small shallow clam holes that then got filled. These pieces would be the cast from that surface.

 

There are no identifiable "burrows" in any of the pieces I've found although I have 1 small piece where the "bumps" have a longer aspect ratio. I'l get a picture when the sun comes up. 

 

 

I didn't take a picture of the pieces I sent to Roger Chris, but they all look about the same except for the small piece I'm going to take a picture of this morning for Harry.

Hey John, thanks for the reply.. I should have said this earlier but I was particularly interested if they all showed "linings" especially one of the cauliflower shaped ones. I think that might be one of the keys to the ID. 

Regards, Chris 

Edited by Plantguy
added detail
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Sacha
34 minutes ago, Plantguy said:

Hey John, thanks for the reply.. I should have said this earlier but I was particularly interested if they all showed "linings" especially one of the cauliflower shaped ones. I think that might be one of the keys to the ID. 

Regards, Chris 

 

Not sure what you mean by "linings" Chris.

 

@Harry Pristis Here are pictures of the little piece.

 

DSCF1980.thumb.jpg.e70b0ef28e152456ec50944330e18e92.jpg

 

DSCF1982.thumb.jpg.28a6139e3402f2adbdc23ea0a02ed72d.jpg

 

I think I could see these as casts of a colonial type of bivalves protective "burrow". Especially as Roger says "complete" (the rounded bumps) and "partial" (the broken off bumps) borehole linings. We'll see what he says in his response.

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digit
24 minutes ago, Sacha said:

Not sure what you mean by "linings" Chris.

I think (with my limited understanding) that burrows of crustaceans (mainly shrimp) which are often made in soft muddy environments are often lined with fecal pellets to strengthen the walls and keep them from collapsing. I would not think that mollusk burrows would be so lined as they would lack the dexterity do to so.

 

Looking forward to hearing Roger's clarification so that we too will learn a bit more about Lithophaga.

 

 

Cheers.

 

-Ken

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Sacha

Here's Roger's update. @Harry Pristis, @digit, @Plantguy...a colonial mollusk.

 

"Correct.  These are multiple specimen closely packed together.  Lithophaga and several other bivalves (e.g., Botula; Gastrochaena) bore into rock and coral. Sometimes the coral or rock erodes/dissolves away leaving behind the borehole linings.  Next time you find a coral head with holes in it, break it open to see some of these in place."

 

Now, as an aside, I've soaked the little piece in vinegar for the last 3 hours and had no reaction at all. So I would surmise that the original limestone surface with the depressions on it was covered in a silica rich ooze which hardened and then the limestone eroded away leaving the casts of the multiple depressions. In this layer at Zolfo, there are plates of chert with cemented silica sand and the limestone or dolostone is gone. This sits on a clay layer (usually) with dolostone below that.

 

 

 

 

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Harry Pristis

I guess different clams leave different "borehole linings."  The clams that bore into dugongid ribs leave no linings that I've noticed. 

 

dugongribborings.JPG.82cc3f2671a2b227307b3ff173863a14.JPG

 

coral_dichocoeniaB.thumb.JPG.46c18abc65924a5b8556385b26711e83.JPGcoral_dichocoeniaD.JPG.95a5191a5cfc83605424e4416d5a9b1e.JPG

 

 

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Sacha
Posted (edited)

I guess so.

Edited by Sacha
clarification
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digit

Thanks for the update.

 

 

Cheers.

 

-Ken

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