Sunday, March 2, 2014

Handaxes and San Pedro Shootout




Hi all,

Recently, students of a Texas A&M anthropology course processed animals with Acheulean handaxes and also observed projectile point penetration on fresh animal hide.  I made the handaxes from chert nodules that I liberated from parking lot medians here in town and the San Pedro points from quartzite and obsidian.  Students conducted many other tests, including skeletal damage cause by blunt force trauma and burn patterning on animal bone.

Beginning in Africa. ca. 1.7 mya, and extending until ca. 100,000 years ago, Acheulean handaxes were in use for a staggering amount of time.  The production and use of these teardrop-shaped tools and associated flakes extends from South Africa to Northern Europe and Asia.  The Acheulean technological complex focused on the production of large cutting tools such as bifaces, large flake tools and large cleavers.  For this study we tested differences in applicability between a handaxe and the flakes produced during manufacture for the task of fleshing and separating sections of a carcass.  The flakes removed to produce the handaxe offered precision cutting tools while the resultant axe provided a sharp and heavy implement for separating joints and crushing bone to collect marrow.      



Students use Acheulean handaxes and observe cut mark patterning

For the next test we set out to see how San Pedro points perform as armed darts.  I have a bit of a soft spot for these after seeing one positioned over a much later stone-sealed offering pit in New Mexico.  The ease of production, durability and wide cutting edge makes this morphology especially attractive.  The darts performed quite well and roared through the fresh sheep hide without issue.  However, going home with a handful of unbroken darts would be boring so we kept shooting until the points broke.  The quartzite point was by far the most robust projectile, no surprise there.  The obsidian points performed well and left very clean puncture wounds.  The barbs created by the notched corners functioned fantastically well, so much so that the darts had to be pulled out through the target from the back.

The arrow I had made from river cane growing in the backyard felt better than the shorter version I had made the week prior.  The added length kept the foreshaft joint off of my hand while at full draw.  This arrow flew true and had no issue passing through fresh hide.

Lower half of target had hide and rib sections for impact tests. Upper portion had hide on cardboard backing
Arrow made from backyard river cane with turkey feathers
This Tularosa Corner Notched (ca.1100 B.P.) on composite arrow performed well

First in a set of San Pedro points ready for flight test (Southwest U.S.,ca. 3500-1700 B.P.) .

Quartzite San Pedro #1 impact on bone through hide
Dart #2, hafted obsidian San Pedro point
San Pedro #2 through sheep hide
Surprisingly, San Pedro #2 split through this branch with minimal tip damage

San Pedro #2 eventually struck bone directly under the hide and shattered

San Pedro #3
San Pedro #3 damaged tip after a few ground impacts and a glancing strike on bone through hide
This Pueblo Side Notched arrow point still pushed through after three resharpening events

Saturday, February 22, 2014

Making and Breaking

Hi all,

For the last few weeks I have been producing projectile points and armed darts for a Texas A&M course focused on taphonomic processes.  This course, led by Dr. Darryl de Ruiter, illustrates how animal bones found in the prehistoric record offer evidence of human behavior and natural post-depositional processes.  For instance, differences in impact damage from projectile points and cut marks on bone from butchering may show changing subsistence strategies over time.  We have used stone-tipped arrows, atlatl darts, metal spears...all sorts of fun sharp things.

My part in all of this is to provide a healthy supply of projectile points and other stone tools for use in these experiments.  I have been having a blast and thought I would share what we have been up to so far.

As always, it's been fun to make functional points and destroy them.



Producing stone tools with students for a butchering experiment
Angela Gore testing obsidian point damage on bone
Antler composite point without  binding or inset blades

The durability of this point style surprised us all

Antler point damage from impact with bone


Hafted Folsom point ready for impact damage test
Impact damage from cow head on Folsom
Similar damage pattern on Folsom from Kincaid Shelter, TX. Photo: Texasbeyondhistory.net


 
This Folsom point passed through the throat with no trouble
Josh Lynch launching a Folsom point. Look at the flex in that dart!
 
Clovis point wrapped and ready
Clovis point entrance wound

Clovis point impact damage on cow bone

Tuesday, February 4, 2014

Testing the Third Notch


Hi all,

 CLICK HERE TO SEE THE TEST VIDEO

The presence of a little third notch on Bonito Notched and Temporal points has interested me for a number of years.  I first saw these point types in person in 2011 while helping teach for the Archaeology Southwest Field School out in southwest New Mexico.  These points were made throughout the western half of New Mexico and into eastern AZ.  I wouldn't be surprised to see these points in northern Mexico given prehistoric interaction.  People made these points during the Late Prehistoric period, Pueblo II to III time frame, placing them around A.D. 950-1150.  Bonito points were in vogue in Chaco Canyon during the Classic Bonito phase (A.D. 1020-1120) when construction at the massive Pueblo Bonito was completed.  Check out Justice 2002:254 for info on how these relate to earlier Chaco point forms.  Bonito points were contemporaneous with non-triple notched points for some time, as both types have been found together in excavated arrow bundles at Pueblo Bonito (Judd 1954).
Temporal Point from Fornholdt Site, Mule Creek, NM
 
Temporal points occupy a more southerly region and are more or less restricted to southwest New Mexico and eastern AZ. These points also have a third notch along one margin and date to the Late prehistoric; around A.D. 900-1200 is a good ball park date range.

The points were typically made from flake blanks and often exhibit the original flake scar from core removal.  I can typically produce a point of this kind within 15 minutes.  They are thin, sharp, and a welcome asset to any quiver.

The third notch was not used as an additional element for hafting the point to a foreshaft as hafted points have been found at Pueblo Bonito with sinew wraps only around the lower two notches (Justice 2002:41; Cosgrove 1947).

So, is a third notch on one side a technological advantage, or should we look outside of technological function to explain this attribute?


Area of Fornholdt Site, NM with mule deer in distance

The Test

I wanted to see if the single third notch along one side aided in consistent and predictable fragmentation.  If the points failed to show a clear advantage over serrated points or normal point breakage patterns then we might start entertaining ideas of social, rather than technological function.  for a pilot study I created five hafted points with a single notch on one side.  These points were shot with a recurve bow into meat targets until breakage was achieved.  The broken points were observed for breakage patterning to understand technological function versus a more vaporous social marker.

Set of Bonito Notched and Temporal points ready for hafting

Hafted points with a third notch along one side

Results


All points functioned well and took several hard impacts prior to any sort of impact damage.  As always, I would want more data.  Only one point exhibited a break along the third notch.  All others broke at the tip or at the intersection of haft and point, where in my experience a majority of breakage occurs during impact.  At this point I cannot comfortably attribute the single third notch as a technological advantage over serrated points or straight-edged points.  The third notch did not make breakage patterns more predictable, nor did it make the point into some kind of frangible arrow point.

The remaining points show no strict breakage patterning
One point broke along the third notch

Temporal point going strong after several impacts
 Discussion

I can see why we would think the third notch functioned as as technological advantage.  for instance, perhaps the third notch was a quick way of making the point break apart on impact with bone, which is a good thing in some cases.  But, this was not the case.  The points broke in relatively normal order.  In fact, the points took just as much of a beating prior to breakage as any other point.  I had to shoot the points through sinew and light bone up to five times before any type of breakage occurred.  This is of course luck of the draw, as one major bone impact on the first shot would cause a break.  But, at the end of the day, shot after shot, the points did not show any superiority in breakage patterning to other points tested so far.  Perhaps in this case we have a social function or marker of time and place flaked into stone rather than strict technological choice.  More tests will help, but for now I have been persuaded to look at these types as a mark of identity, rather than technological/functional adaptation.  Possible social functions? Your guess is as good as mine.


 Happy Hunting



Refernences:

Cosgrove, Cornelius B.
    1947      Caves of the Upper Gila and Hueco Areas in New Mexico and Texas.  Papers of the peabody Museaum of American Archaeology and Ethnology, Harvard University 24(2).

Judd, Niel M.
    1954      The Material Culture of Pueblo Bonito. Smithsonian Miscellaneous Collections Vol. 124.

Justice, Noel D. Stone Age Spear and Arrow Points of the American Southwestern United States
     2002      Indiana University Press, Bloominton, Indiana.




Monday, January 27, 2014

Flake Tools and Deer Hide


Hi all,

The other day my friend Angela Gore shot an Axis deer near Fredericksburg, TX and brought the hide over to begin the fleshing and tanning process.  Angela is interested in Upper Paleolithic and Paleoindian archaeology focused on the peopling of Beringia and the Americas, specifically patterns of human dispersals, hunter-gatherer ecology, and human behavioral adaptation.

What's really cool is that she brought along a ton of raw chert local to the area where the deer was taken. This locally available raw material is commonly known as root beer chert and is a minor lithologic constituent of the larger Fredericksburg limestone, dolomite, marl, and chert group. High quality nodules from this group knap very well and offer a more durable alternative to obsidian.

Axis deer hide ready for work
Fredericksburg root beer chert nodules

 We decided to perform the task with local raw materials to see what it would have been like to process a deer hide as a Central Texas forager.  The abundant raw materials allowed us to use expedient flakes taken from a core to flesh the hide.  Informal tools are made when minor design constraints are present such that little to no reshaping of a flake is necessary to complete a task.  In an instance of raw material scarcity, our technological choice may have become centered around a more formalized flake core to preserve our stone.  In this case I created blade-like flakes (more than twice as long as wide) from a single-platform core and produced more as initial flakes became dull through use.

Flake core with parallel removal scars and partially fleshed hide


When lithic specialists think of hide processing we sometimes focus too much on formalized scrapers.  Formal scrapers are the most iconic implement, yet are only one member of a much larger tool kit.  Interestingly enough, for our task, sharp flakes comprised the entire usable assemblage for the initial stage of fleshing.  The scrapers that we tested did laughably little to separate the tough membrane from the hide.  Formal scrapers will play a dominant role in the next stage of scraping the residual tissue once the hide is salted and soaked.  Salting the hide removes fats and oils that decompose and lead to hair loss on the pelt.  In this way each step includes a dominant tool assemblage that plays a key role in the multistage process.  Overlap in tool morphology no doubt exists as trimming with sharp flakes will accompany the formal scraper use later.  As far as site formation process goes, the initial fleshing leads to the production and eventual discard of several large, sharp flakes while the ensuing hide scraping produces small retouch flakes as scrapers are resharpened.

Angela uses a sharp flake to cut flesh from the hide


Visible use wear on the fleshing flakes took the form of a dull continuous polish along the cutting margin with minor flakes removed to dull sharp areas that came in contact with hands.

This sharp curved flakes worked very well.  You can see residue along the working portion of the flake

All in all a very fun experience that reminded us both of the compound nature of tool production, use and discard during a single hide processing event.  Additionally the task helped to reinforce the usefulness of expedient flake tools and the importance of tailoring production techniques to raw material availability.

Happy Hunting!         

Wednesday, January 15, 2014

Oh, Snap! Obsidian Knife Breakage

Hi All,

I hafted the fluted obsidian knife from the other day and took it out for a test in the Piney Woods of Deep East TX.  I (unsurprisingly) did not manage to get a deer or wild hog this time.  I did, however happen upon a rabbit.  These rabbits have been a real hit at cookouts with the neighbors, no really.

The Test:

In keeping up with thrashing nice things, I used the hafted knife to process a rabbit in a similar method seen in the previous rabbit knife post. The materials used did not change: obsidian knife blade, antler handle and pine pitch glue.  Rather than keeping the cutting edge centered along the tool's cutting margin, this time I played with a slight bevel.  This was supposed to be used in a test of resharpening efficiency between beveled and mid-line margins.  I had misplaced my metal knife so i set out on another functional-recon experiment with what I had laying around.


Hafted knife with beveled edge created along lower cutting margin



Results:

Unfortunately, I had little chance to observe differences in beveled/centered cutting edge performance as the blade snapped during rib cage separation.  I had inverted the knife, using the curved edge in an upward direction to open the rib cage from the inside.  This task did not bode well for this specific tool.  The event was signaled by the broken blade flying across the workspace that left a spiral of blood stretched across the ground.  So...pretty cool to see actually.  Try it for yourself sometime as a party trick, no?

The catastrophe resulted in a strange hinge fracture that traveled from margin to margin and split the piece in half.  The crack initiated from the curved section of the tool as force was applied upward.  Bending stress increased upon the fulcrum created at the junction of blade and handle to a sufficient degree such that the applied stress overcame the performance capabilities of the tool.  The fact that this was a fluted knife may have something to do with the breakage, as the channel flake eliminated the typical lenticular cross-section that usually works so well under bending stress. 


Blade held as used during fracture.  Fracture initiated from top to bottom

Oblique distal view of vertical bending stress fracture



Discussion:

Is this type of breakage specific to knife use?  I have never seen a hinge fracture like this as the result of horizontal impact damage.  Perhaps this type of breakage is associated with vertical bending stress during butchering events.  More tests are needed, as usual, but his seems to be something special in the world of task-specific breakage patterns.

The following images illustrate how this piece broke.  I have found that inverting the image is a simple way to see flake scar patterns slightly better.  There are some great new imaging studies out there that are revolutionizing our ability to assess flake patterning.  Inverting the image colors on obsidian is a quick and dirty way to see a piece in another light, plus it looks cool.







Let me know if you have seen anything akin to this type of stress fracture.

Happy Hunting!  

Saturday, January 4, 2014

The Cost of Education

Hi all,

Shaping stone is a timeless language, each flake a word, each tool a statement of place and time.

At some point along the line I convinced myself that learning how to remove channel flakes (fluting) was a good idea.  If I lived near a large raw material resource this would be less of an issue as I could go destroy preform after preform while gradually learning the intricate process of creating a channel for hafting with a single strike.

The concept of channel flake removal is quite brilliant and usually accompanies other techniques that require a lot of practice to master.  In brief, a channel flake is a single flake removed from the base of a biface that serves to create a long, thin area for the haft to fit.  This method allows for a relatively robust point to be hafted into a usable dart.  Without this special type of haft preparation the projectile would simply be too thick and the weight of the stone point and accompanying (gigantic) haft would render the weapon delivery system physically inept.  I'll test that situation soon.

The ability to remove single flakes from the base of a point led to some absolutely fantastic lithic traditions.  Clovis, Folsom (my personal fav) and Cumberland points all used this method to varying degrees.  But what is the learning curve like? It can't be all that easy...but is it really all that hard?  The fact that we find fluted points means it is by no means impossible, and other modern knappers do it all the time.  On the other hand, we find channel flake failures all the time too so it can't be that simple.

Folsom preform with overshot from the Lake Ilo site, North Dakota. Photo: litchiccastinglab.com


In this test I set out to see what the learning process looks like.  Do my attempts at channel flaking mirror the artifacts we find in the archaeological record?  What of my failures, do they look like unsuccessful attempts visible archaeologically?  This is just the beginning of a long-term project to document the learning process for channel flake removal.  Most folks like to show the best products of their endeavors, as if the skill set became magically integrated within one's motor skill vocabulary.  Here we enjoy the process and observe the punctuated nature of success. So, here we go.

The Test:

I decided to try a few different point types that used the method of channel flake removal.  Specifically, i thought I'd try my hand at fluting Clovis and Folsom preforms.  As part of my job is to identify and describe Paleoindian sites in New Mexico, it is to my own benefit to produce and observe the kinds of flakes produced by these early foraging communities.  I used obsidian for most bifaces as the ease of flake removal is well suited to this sort of task.  I decided to not go overboard with the channel flake removal apparatus.  Take a look around the internet and you will find some methods that work well, like giant milled metal lever devices.  while a cool modern technological innovation, metal lever devices create assurance and steal adventure, grit and risk right away.  I wanted to see if freehand percussion would work sufficiently, given practice.  The answer is yes, by the way.  There are plenty of great ways to remove channel flakes and freehand percussion is just one method.

Results:

Creating a channel flake before trimming the point to final form saves time and energy.  There seems to be no good reason to spend time making a perfectly symmetrical point, then fold it in half due to a failed flute attempt.  Once the channel flaking strategy is a success then spend time on aesthetics.

My initial attempts resulted in catastrophe.  But, in time my failure has begun to mirror problems evident in the archaeological record.  Hey, at least I am failing correctly.  There has been some success though. Several channel flakes traveled well and thinned the biface into a usable item.  The channel flaking failures, typically when attempting Folsom preforms, carried too far across the surface and removed the opposite tip.  This unfortunately reduced the final size of the item.  Reduced length means less cutting edge, less material real estate to work with and ultimately translates to less blood loss on impact.  These factors are serious attributes when attempting to kill a large angry "something" with a rock.

Lessons Learned:

Read around and you will find that creating a convex cross section is key.  To little surprise, convexity in the preform turns out to be essential.  Just like blade removal from a core (see microblade posts) flaking some convexity into the preform creates a mid line for the channel flake to follow from base to tip.  Again, unsurprisingly, platform preparation is essential.  Experience suggests uncalculated hope offers little comfort.   I am still not satisfied with my platform preparation technique.  I have seen some fantastic examples out there and my method needs refinement.  A little thing called "mapping" is helpful.  By grinding the face to be fluted with a stone one can observe the most prominent area of convexity and build a removal platform accordingly and apply force from the most appropriate direction.  Things will continue to get better from here.  I'll be excited to keep working on this technique.  There are some real masters out there, check it out on youtube if you are interested.  Oh, and hey...you don't need a fancy metal flaking leverage jig to get the job done.

 Take a look at the images below to see how things are working out.  This is the start of something fun, we'll see how my technique improves over time.

Happy Hunting.



This raw novaculite was very plastic feeling and resulted in multiple step fractures
I decided to flute this knife blade


Here is the support method that I use for direct percussion fluting
Overshot flake on Folsom preform
and yet another
This channel flake terminated early when it hit a stacked area

Overshot result on Folsom preform
Let's keep this party going! Yet another overshot
Novaculite channel flake