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Geologic material question -Fine-grained basalt or Siliceous ooze?


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Every now and then I find something odd on the ground in the backcountry. Do not feel this is a fossil.

 

At first glance I thought this was just some siliceous ooze with intricate folds. At second glance I noted the broken surfaces were not conchoidal as one would expect with silicate materials. It almost appears like extremely fine-grained basalt on the broken ends

 

Specimen is 1.5" (38mm) long and 1.25" (32mm) wide. Thickness is 3/8" (8-9mm)

 

I'll call this the top view. Primarily very dark black

 

weird2b.thumb.jpg.fea610b35100fe6156a44d553eb12d56.jpg

 

Bottom view has a decided reddish cast in places. Note the broken end on the left. 

 

weird7b.thumb.jpg.16614df71e8c551e9559dacbe464f805.jpg

 

Another broken section on the side. Small vesicles. Some strange inclusion on the left.

 

weird4a.thumb.jpg.ccfecf8ceb1181bb90883e9b88ecd3dd.jpg

 

Another exposed side section

 

weird5c.thumb.jpg.d04aa04235ddc4ed0d2626e61818614d.jpg

 

If it is igneous in origin that would be interesting because the closest igneous activity is about 70 miles away and would imply transported in by ancient peoples.

 

Any geologic thoughts to send my way?

 

Thank you, Kato

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Slag

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1 minute ago, grandpa said:

Slag

@grandpa

 

If close to a town or mine I could entertain that thought...no town, mine or human habitation within 3.5 miles and this was found in a very remote back canyon near a small natural spring.

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yardrockpaleo

Bottom view bears resemblance to an ichnofossil, but that is improbable. I guess some type of extrusive Igneous rock, though how it got there is completely open for speculation. The Native Americans did highly value obsidian and pumice, which seem to be similar to this rock.

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1 hour ago, yardrockpaleo said:

Bottom view bears resemblance to an ichnofossil, but that is improbable. I guess some type of extrusive Igneous rock, though how it got there is completely open for speculation. The Native Americans did highly value obsidian and pumice, which seem to be similar to this rock.

@yardrockpaleo

 

Your comments got me thinking about hawaiin lava types. Looked at aa and pahoehoe articles. This is a photo of pahoehoe

 

image.png.6e017b44ce14b08f5a26fb095e91f7b0.png

 

 

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LabRatKing

I agree with Kato, this is pahoehoe. (pronounced paw-ho-ie-ho-ie) as opposed to Aa (ah-ah) which is like the lava you put in your grill or flower bed.

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