Bones

[geomorph]

Hello, found on a glacial fluvial outwash plateau in eastern Washington state, probably around late Pleistocene/early Holocene. They were found next to each other and appear to fit together.

 

 

[Ludwigia]

Those don't look like bones to me, although the resolution of the photos isn't good enough to be able to judge properly.

[Rockwood]

Agreed. It might be worth a closer look to rule out heavily silicified bone, but it seems unlikely.

[geomorph]

Thanks for the feedback, yes, everything in the feature appears to also be heavily silicified. Here are some more pics, microscope at 100x for all.

 

Is there anyway to determine heavily silicified bone without cutting it open? One micro view shows a scratch on the "enamel."

[jpc]

they look like chert nodules from here.

[Fossildude19]

I agree, chert nodules. 

Or perhaps the same nodule, broken apart. 

 

[geomorph]

Initially I thought the same thing, but after looking at two different pieces of chert under 100x there appears to be a texture to the chert, whereas, the nodule is much more dense/smooth, at the same 100x magnification. The translucent white picture is the nodule, and the textured picture is the chert: 

[JohnJ]

Quartz based rocks, like chert, can vary in surface texture depending on their composition.  These rocks only share a vague similarity in shape with bones.

[Rockwood]

The 

3 minutes ago, JohnJ said:

Quartz based rocks, like chert, can vary in surface texture depending on their composition.

Fresh powder snow vs the stuff in the ditch. 

[grandpa]

I would call these chert "rocks".  But I love your interest in fossils and things geological in general.  Keep on "looking down"; there are a wealth of treasures below our feet, if we only choose to discover them.  AND - you have found a great place to support your interest and curiosity in things geological.

 

As for "chert", this is a term for crypto-crystalline quartz.  The size of the micro-crystals of quartz/silica can vary widely.  Crystal size is determined by how slowly or rapidly the silica solution cooled and thus how large the crystals were able to develop before being "frozen" into solid form.  Rapid cooling yields small (i.e., micro) crystals.  Slow cooling allows the crystal to develop into macro-crystals.  There are many levels of crystal development from the most micro of crystals (think agate) to the development of large quartz crystals.  Your example appears to be fairly "grainy" which would indicate an intermediate level of cooling and crystal establishment.

[Fossildude19]

I would add that a fresher break would look different from a weathered surface. 

[geomorph]

What a rush of knowledge, big fan of the site thus far! Yeah, that is what was throwing me for a loop, the micro variation in crystal structure (I also looked at a freshly broken milky chert, I just did not post it)... sorry, just thinking, I do not think the “sidekick” piece pictured is chert though, seems porously-lightweight and not as dense. When I get home I will scrape some of the silicate off and see, as I have another piece, hexagonal, and more similar to the sidekick.

Edited November 26, 2019 by geomorph

[geomorph]

Pictured below is the sidekick piece which appears "patterned/stained" on the inside. Also, the third piece appears very white and snowy in the micro image. 

[Rockwood]

Sorry, but I don't see any features that are consistent with it being bone.

[jpc]

40 minutes ago, Rockwood said:

Sorry, but I don't see any features that are consistent with it being bone.

me neither.

 

[geomorph]

Hmm. Yeah, after cutting through the two that are lightweight and powdery and looking at them under the microscope it appears as though everything is coated in a thin silicate (?) enamel. But, the interior of the two powdery ones seem like a calcium carbonate, while the interior of the micro-grained white chert one should be a cryptocrystalline silicate... So, I just recalled that I have some muriatic acid (14-29% hydrochloric acid) at home, this evening when I get home I will drop some of that on the two lightweights and see if there is any reaction.

 

Thanks to everyone so far! I am learning as I am going forward. Much thanks.

 

— also, I am curious, what does bone look like right before it completely decomposes/disintegrates?

Edited November 27, 2019 by geomorph

[Rockwood]

2 hours ago, geomorph said:

what does bone look like right before it completely decomposes/disintegrates?

Bone

[Rockwood]

Small fragments are dispersed, dissolved, or distorted by settling of the sediments, but overall something like this is still what we are looking for usually.   

[geomorph]

Thanks Rockwood! Well, the lightweight pieces that I have are definitely not fossilized. The muriatic acid blasted through the patterned/stained one in about 15 seconds, leaving behind about 40-50% of an off-white substance (phosphorus pentoxide?). I do not know, but I will check it out closer, later on. The other piece sat in the acid for 3 minutes with no reaction. 

 

 

--- I remembered hearing something about Chinese Bone Ash China (plates and cups), and how real animal bone was heated to about 2,000 degrees Fahrenheit, ground up and then the milky white bone ash was used to create the dinnerware. 

[Rockwood]

Alchemy to me.