Topic ID #30027 - posted 10/23/2013 9:20 AM

Artifact or Geofact?



AED

It's been quite a while since anyone has posted an "artifact or geofact" query here, and I'm sure everyone has been desperately longing for another one, so here goes.  Please take a look at the photo shown at this link:

PHOTO

This piece of hard limestone was uncovered from about 20 cm down in dense and apparently undisturbed clay by a lady tilling for a new garden on a hillside in eastern Muskingum County, Ohio.  What do you think?  Artifact or geofact?  Please explain your reasoning based on what you see in this composite photo.  I'll respond after a reasonable number of you have replied.  Thanks for your time.

    Alan




Post ID#20302 - replied 10/26/2013 2:00 PM



DougRM

I would say geofact. I can't really see any sort of human changes to it. I see that there are some sort of scratches across it BUT from the photos I can't tell if it didn't just happen from natural processes or maybe from the lady tilling a new garden.

Post ID#20304 - replied 10/26/2013 2:10 PM



Natty

I would say geofact. The striations on the notch look like tilling damage. Yes, the striations run both horizontally and vertically, but that could have happened if the piece was turned sideways by tilling. I don't see any other evidence of human handling.

Post ID#20305 - replied 10/27/2013 7:06 PM



AED

Hi Doug and Natty...

Thank you very much for your observations.  It's nice that after now 317 viewings of this piece (presumably by quite a few people) two archaeologists feel confident to assess a stone that is not a flint projectile point.  (Anyone else like to weigh in?)

It occurred to me that I was remiss in not stating the dimensions of the rectangular area shown lower right in the photo.  The width of this area is about nine millimeters, and the photo was taken under about 10X magnification.  The surface is smooth, shiny, and well patinated along with calcite deposits.  Under the binocular microscope with illumination at a low angle across the surface, the parallel and subperpendicular striations are seen to extend to a very shallow depth beneath the surface.  You may want to consider all this with respect to the tilling damage hypothesis.

Later...    Alan

Post ID#20306 - replied 10/28/2013 4:53 PM



StarRider


Glacial striations, geofact.

Post ID#20307 - replied 10/29/2013 7:47 AM



AED

Thanks, StarRider - interesting idea.  From the information presented in my initial posting, which glaciation do you think is responsible for the striations on this stone?

Post ID#20308 - replied 10/29/2013 1:51 PM



StarRider

That would be difficult to say, as if it was found in "apparently undisturbed clay" then it's likely outwash. The patina in the magnified photo would suggest the striations have been there quite a while, but like the others I see no indication that they were caused by human action.

Post ID#20309 - replied 10/30/2013 8:22 PM



AED

Hi StarRider...   A glaciation map can be quite helpful in matters like this, and actually something one should look at before proposing glacial abrasion.  Here's a good one for Ohio:

OHIO GLACIATION MAP


Does this map, along with the find location given in my first posting, give you some further insight?

Post ID#20311 - replied 10/31/2013 6:44 PM



AED

Thanks for the observations, StarRider.  Apparently the only known surface remains of even pre-Illinoian glacial drift in Ohio are present in a small area near Cincinnati (southwestern part of the state), as shown on the map.  Do you suppose the highly regular and presumably natural striations on the rock are compelling evidence of pre-Pleistocene glaciation in southeastern Ohio?  This could be important...

FYI, here is another photo showing some additional polished surfaces on this stone (there are a total of nine of these altogether):

PHOTO2

Again, input from others in this forum is welcome and encouraged.

Post ID#20312 - replied 11/1/2013 12:41 PM



DougRM

Well after looking at that second photo, yes 99% geofact. I would like to hold it in my hands to be sure but  until technology is there I will just stick to a 99% sure it's a geofact.

As starider says, Glacial striations.

Post ID#20314 - replied 11/1/2013 3:12 PM



fresno


Looks like something straight out of a publication someone gave me, Stone Effigies of the High Plains Hunters by James Gaskins.

Post ID#20315 - replied 11/1/2013 10:03 PM



AED

Hi DougRM and fresno...  Sorry I'm a bit slow in replying - lots of other stuff going on.

Doug, you figure we do actually have evidence of pre-Pleistocene glaciation here?  Maybe so, since the 300,000,000-year-old Pennsylvanian sedimentary bedrock is just beneath the surface.  And it seems this glacier took an unusual path, since the pretty much identical striations run nearly perpendicular to each other.  Apparently the glacier came to a dead stop then took a hard left or right.  Interesting...  Also, since the stone in question is local limestone, it must not have been dragged very far for some reason.

Fresno, you say "stone effigies"?  Does the morphology of this stone suggest anything other than a random naturally abraded rock?  Please explain if you would.

Post ID#20316 - replied 11/2/2013 5:24 AM



DougRM

Without knowing context it would be very hard to say. Rocks move. Is it undisturbed clay or is undisturbed clay after it was laid down by construction 20 years ago that came from somewhere else?

Are there streams or other natural process that could have moved it?

What is local limestone? What sort of area does it cover? Could it have come from somewhere else?

I really don't have enough info to make any sort of claim other than the striping looks natural. Something that could easily have occured at pretty much anytime. I say glacial but it could be some animal or river causing the scrapping.

Honestly, couldn't say more than it does not look like humans made scratches on it on purpose.

Post ID#20319 - replied 11/4/2013 7:44 PM



AED

Doug, thanks for your assessment.

Quite likely this hard, dense, and rocky clay terrain was not disturbed within the historical time frame, given that the area was woodland relatively recently cleared for grazing.  There's no stream on the hillside, but of course the stone could have slid downhill before it was covered.

The limestone seems typical of the local Conemaugh series (possibly Ames or Summerfield member), which, directly northward, extends about eighteen miles, so StarRider's proposed pre-Pleistocene glacier could have moved it that far.  (Likewise to the north, the closest Pleistocene end moraine is about forty miles from the find location.)

Anyway, after over a thousand views in a professional archaeologists' forum, we now have four proposed natural causes of the striations on the stone's polished surfaces:  tilling, glacier, animal, and river.  I'm rather surprised that two other stock explanations have not yet been presented:   fossil and natural crystal structure.  Would someone like to comment of either of these two possibilities? 

Post ID#20322 - replied 11/6/2013 9:10 AM



xenophon42

Will also have to go with geofact.

Being found in a solid clay matrix, and all the other factors, like the the thin  cortex developed over the striations, pretty much indicate any modifications to this piece of limestone happened long ago and were of natural origin. Most likely a combination of glacieral abrasion polished by time and sedimentary wash.

Post ID#20330 - replied 11/11/2013 9:16 PM



AED

Ok, the professional verdict seems to be abrasion and polishing by cryptoglacial action, or possibly by some other unexplained natural force not involving a human.  Before I take this any further, I wonder if any archaeologist here sees in this stone anything that might suggest to him/her that a human had a hand in this.  (Hint:  Fresno may have suggested something.)  Thanks!

Post ID#20331 - replied 11/12/2013 5:41 PM



diginit

The third picture shows a rhombohedral like planar structure to the material which is in turn reflected in the angles seen in the "bird" like features, then it just peters out to a disorganized structure.  I don't remember from my geology classes which minerals exhibit this fracture property, but I don't recall any from school that were known to have been selected by prehistoric peoples. This may be able help you source which glacial till source it came from.  Unless there is blood residue from where it was used to bludgeon something I am pretty sure it is non-cultural.

I can see what the others are saying about the glacial scouring/ striations (pic 1), but again I do see a cross-pattern to the close up that is neither perpendicular or random in nature.

Good Luck!

Post ID#20339 - replied 11/15/2013 10:17 AM



fresno


AED wrote: Fresno, you say "stone effigies"?  Does the morphology of this stone suggest anything other than a random naturally abraded rock?  Please explain if you would.

I think it is natural, as are all of the effigies in the book I mentioned. Out on field survey, I tend to come across a lot of "geofacts". I am usually skeptical about isolated findings. I might give yours more consideration if it was found among a scattering of obvious prehistoric artifacts.

Post ID#20347 - replied 11/21/2013 6:11 PM



AED

Hi diginit, StarRider and fresno... Thanks for your observations, and for the 
photos of Middle and Late Archaic figure stones. Nice!

So, artistic virtuosity and blood/bludgeoning are expected attributes of a 
"cultural" object? Duly noted...

Speaking of Archaic Period, have a look at this quartzite piece an amateur archaeologist 
from Ashe County, NC showed me summer before last. He recovered it from about half a 
meter down on his property, in context with projectile points diagnostic of Early to 
Middle Archaic. It was about 15 cm directly beneath an apparently Early Archaic point. 
The red and black material, differing in color from the stone's exterior surface but also 
natural, seems to have been exposed on this hard rock by impact from one source or 
another. While I suspect you will see this as a geofact, given its rough appearance, I 
think you might find it interesting:

NC QUARTZITE
Back to the limestone piece in question: Fresno, you're quite right in saying the presence or absence of cultural material in context is relevant. (I'm more or less surprised that no one else here has mentioned this.) But as indicated in my initial posting, I wanted to know what professional archaeologists can find in just the (fairly high resolution) photos. Sort of a "blind test" of what they can see from the perspective of whatever geology/petrology they might have encountered in their archaeology curriculum. Diginit, nice that you see a birdlike morphology in this stone. Artifact or geofact, the resemblance is rather obvious, isn't it? Judging from the overall response to this, I suspect that most here have found the discussion tiresome by now. So, after I've dealt with some pressing everyday chaos, I'll end it with the more complete story of this limestone and its evaluation by Ohio's state archaeologists and a petrologist / geology professor. Meantime, further comments are welcome as always.

Post ID#20357 - replied 12/10/2013 12:33 AM



AED

Here's the long awaited(?) background story:

The lady who uncovered this piece gave it to me since she knew of my interest in bird-form artifacts.  Being a fellow amateur radio operator, she had earlier been digging into the ground on her hilltop property while preparing antenna foundations, noticing numerous small more-or-less bird-shaped limestones, none previously quite so compelling as the one presented here.  Looking at it under the binocular microscope, I thought it to be a good artifact candidate.  As I've often done for a sanity check, I emailed the photos shown here to my main rock consultant Dr. Eric Law, professor of geology and a petrology specialist at nearby Muskingum University.  He thought it worth a look in his lab, and upon close personal examination said he was quite certain the thing was an artifact.  (This is unusual for him, as he is characteristically - and quite rightly - very conservative in his assessments.)

I thought it might be interesting to run the piece past the archaeologists at the Ohio Historical Society, generally presumed to be Ohio's ultimate arbiter of artifact vs. geofact.  They had been proclaiming on their website that anyone wondering about "the oddly shaped rock you found" should show it to them for a determination of whether it is an artifact or "just a rock", so I emailed them the same high-resolution photos.  The quick response from the manager of that group:  "I would speculate that the faceted surfaces and the parallel striations and smoothing were caused by the stone being embedded in glacial ice as it was dragged across the surface at the bottom (or along the side) of the glacier."  And "Certainly I see no clear cut evidence of human modification in the images."  Another in the group, apparently aware of the absence of evidence of glaciation in the area of the find, stated "I would guess that the rock is naturally formed and what looks like striations are actually calcite crystals or crystalization.  They intersect each other too close to have been made by abrasion."  The other members of the staff concurred with the latter assessment. An offer to bring the stone to Columbus for in-person inspection was met with the reply "No value in examining it further."  I then informed them that the professor would author a report confirming artifactuality, and that this would, upon request, be made available to them prior to publication so that they might address any technical errors it might contain.  They declined the offer.

Following is Prof. Law's report on the physical evidence supporting human agency, also addressing the OHS archaeologists' assessments:

--------------------
“This small piece of limestone is micritic in nature, meaning that the calcite crystals in the rock average around 100 micrometers or less in diameter.  This microscopic size rules out any possibility that the linear or facial features visible on this stone are the result of the mineral properties of calcite, such as cleavage traces or crystal faces.

The second distinguishing feature of this stone is the polished facets.  Indeed, the natural process most likely to have produced these polished faces would be glacial abrasion.  However, the most distinctive feature of this small rock is the apparent form of bird head/beak and neck, the features of which are confined to a cross-sectional area of about nine square centimeters.  Within this small area, the rock was polished along at least four different directions in a 3D distribution, with interfacial angles ranging from about 40° to 120°.  Glacial abrasion on rock normally progresses in only one straight linear direction, and its occurring in such a specific 3D geometry within such a small space would certainly be quite rare.  In particular, such a rare case of polishing happening to shape the vivid image of bird head/beak and neck would be virtually miraculous.

One can say with good confidence that the polished facets visible on this small rock are not likely to have been created by any natural process.”
--------------------

Of those viewing this piece in person, almost everyone has recognized it as an artifact.  Notably, this includes archaeologist Richard M. Gramly and rock art specialist Robert G. Bednarik.  The consensus is that the smooth polishing (with attendant striations) was likely accomplished with very fine-grained sandstone.

Regarding fresno's accurate observation that context with "a scattering of obvious prehistoric artifacts", would support an assertion of artifactuality, the site has not been extensively "dug".   Quite the contrary.  Material recovered has been mostly at or just below the surface, and over very small areas.  Being more or less aware of my limitations as a fumbling amateur, I do very little digging.  But other material that has appeared includes nonlocal apparently Upper Mercer flint debitage, chunks of geologically anomalous limonite (yellow ochre), and likewise anomalous pieces of petrified wood (manuports?).

Altogether, I would submit that since rock is the most enduring artifact material composing what our early predecessors left behind, a more technically knowledgeable understanding of geology and petrology than is typically evident among archaeologists (at least here in Ohio) is needed in identifying locations of ancient human habitation.  Those people made a lot more than just flint implements and occasional museum-quality art.




Post ID#20358 - replied 12/10/2013 11:26 AM



Dwarmour

this reminds me of several of your old threads.  Always interesting though AED, it at the least gets people to discuss topics, which seems lacking here nowadays.

http://www.archaeologyfieldwork.com/AFW/Message/Topic/2405

http://www.archaeologyfieldwork.com/AFW/Message/Topic/2842

Post ID#20360 - replied 12/11/2013 10:29 PM



AED

Hi Dwarmour - good to hear from you again!  It's been quite a while.  As I recall, your geology minor stood you in good stead in our various group discussions (using the term "discussions" a bit loosely in some instances...).  You were just getting started in archaeology, I think, and if I remember correctly you found employment somewhere in the southeast.  I sure hope things are going well for you.

In recent years I haven't often ventured into forums, finding it more productive to focus on research and proper scientific verification of the material as time and money allow.  But this forum in particular was quite informative on various levels.  I've managed to get a few articles published, one of them coauthored with the aforementioned geology prof.  More recently, I'm getting set up to render 3D visualization of aerial LiDAR data for a close look at the terrain here in southeastern Ohio, which the Wise Ones in Columbus quite wrongly insist holds little of archaeological interest.  I have some sense of urgency about this, as the ground that has not already been chewed up by surface mining is now being attacked by the hydraulic fracturing people.  Never a dull moment!

      Regards, Alan

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