Unknown Fossil?

[Odinvindr]

I found this in an area of North East China. The area has some volcanic history, and a lot of granite mines. I thought that I had it figured out, but am torn on what type of limestone it is, thus what era it could have formed during, thereby leaving me clueless about the small, potential fossil! Any help would be appreciated! Also, any clues on how the granite became fused to the limestone?

Edited January 11, 2021 by Odinvindr
Here is another picture from the back. Any ideas about the grayish stone? Also, does the limestone appear to be tufa limestone?

[fossilus]

Cross section of a crinoid column?

[Plantguy]

Thanks for the interesting photo! I'm not seeing any granite but we probably need a few more pictures of the other sides to validate that....The gray area just doesnt seem to have any individual crystals/faces which generally show up/make up an igneous rock like granite. It could be a weathered piece of limestone that just has a different mineral content in different layers and/or the colors are different from surface staining. I agree with fossilus cold be part of a cross section of a crinoid or possibly coral. 

 

Regards, Chris 

[Fossildude19]

Cropped and contrasted: 

 

[Plantguy]

Odinvindr thanks for the additional photos.

 

There sure are crystal shapes/outlines in that gray area arent there and the clast has an very angular outline/shape to it and lots of veining.... It appears to have a both a rectangular mineral form and hexagonal shapes and I dont think they are clasts within a sedimentary rock...I dont remember typical granites having that makeup either. Almost looks schist like. Im intrigued! Im wondering if that is actually a metamorphic rock. Not knowing the specific geology I defer to others who have stronger hard rock/mineralogy backgrounds.

A couple of other questions before I close this...Have you confirmed the brown is indeed a limestone and reacts to acid? If you say there is some type of granite in the area if you have some igneous/volcanic intrusions into some nearby/overlaying sedimentary rocks that could alter them even mix things up. Enough of my wild speculations...I'm hoping some of the others will/can chime in and dispell/narrow down/suggest objectively other possibilities...

 

Might be a way to find some pubs/articles on the geology of the area that may hold some clues as well as a possible explanation for the apparent fossil form....Can you tell us what part of China its located in? 

Very cool find!

 

Regards, Chris 

[Plantguy]

I had another question....This other area looks interesting but Im not sure if its just my imagination...Can you take a shot of it looking at it directly--direction of the arrow? It almost looks to be another cross section but the septa/costae are really weathered out showing some relief?

 

 

OK I'm done...need to go watch a football game...

Regards, Chis 

[Odinvindr]

So, I am still gathering all of the information. I believe that I have figured it all out! Have taken a lot of wrong turns, but learned a lot in the process! Once I get all of the information edited, I will post the findings! Thank you all for your help! I really appreciate it!

[Plantguy]

Thanks for the update.  I wouldnt consider asking questions and investigating as wrong turns--just part of finding an answer.  I know we havent established the specific geology of these rocks or your area yet but any time you throw possible igneous-- volcanic/plutonic activity into an area along with normal sedimentary processes things can get changed/metamorphosed and more complex in a hurry.  And just normal weathering of any rock can create some really neat things to find! Good luck with the search! We look forward to hearing more!

Regards, Chris