ENC Summer Interns

At the end of our last session, three of our core team members left ENC and headed to cooler climes and new archaeology. Bryan Heisinger returned to Sequoia Kings Canyon National Park, Emily McCuistion returned to Denali National Park, and Kelton Meyer went home to Colorado to assist on a Colorado State University field school. As sad as we were to see Bryan, Emily, and Kelton go, we are equally happy to welcome our two new summer interns to the crew: Lindsay Vermillion and Kate Richey. Both Lindsay and Kate have worked in ENC before. Lindsay was a summer intern in 2014, and has volunteered on the project over several occasions. Kate was one of our field school students in 2015.

Lindsay Vermillion

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Hi everyone! I’m from Big Bear Lake (a tiny mountain town in Southern California) and am currently an upper-division undergraduate student at Texas State working towards my BA in anthropology, with a focus in archaeology. I have done some work on California’s Channel Islands through Humboldt State University, particularly regarding sea mammal exploitation on San Miguel. This past year I interned with Shumla Archaeological Research and Education Center studying the rock art of the Lower Pecos. I am also involved with the Experimental Archaeology Club at Texas State where I first became acquainted with the Ancient Southwest Texas Project. I have previously volunteered for ASWT and am happy to be back as an intern.

Other Useless Information: I am a classically-trained cook dedicated to sustainability. In my spare time I like to garden, poetry slam, salsa (though I’m not very good at it,) and bask in the sun as much as possible.

 

Kate Richey

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Hi my name is Kate Richey I am from British Columbia, Canada and am entering into my final year of archaeology at the University of Calgary. I participated in the 2015 field school in Eagle Nest canyon where we excavated at Horse Trail shelter. It was my first time out in the field and I had very little idea of what we would be doing or where we would be working and I was amazed when I saw the canyon that we would be working in every day. Last year’s field school was a great experience and so when I found out there was an opportunity to come back and work in the canyon again I had to say yes. Despite the many poisonous animals, the very warm temperatures and the liberal use of jalapenos (none of which we have much of in Canada) I am very happy to be back! So far it has been a steep learning curve but every day brings new finds and things to discuss and I am looking forward to the rest of time I get to spend down here.

 

We are happy to have both of them on the crew and look forward to a successful finish of our field season!

Pigmented Artifacts of Eagle Nest Canyon

By Emily McCuistion

The sheltered limestone walls of the Lower Pecos Canyonlands are known for their complex and well-preserved pictographs, or painted images on rock. Here in Eagle Nest Canyon several of the rockshelters hold within them both pictographic murals on their walls and portable rock art in the ground in the form of painted pebbles. The focus of this blog piece, however, is neither. Rather, pigmented artifacts without clear intentional design, those having a splotch, wash, or stain of paint or pigment, are the primary subject at hand. These artifacts have the potential to relate the rock art on the walls and in the ground to the technologies of pigment and paint manufacture and use, as well as to the other activities of the canyon’s inhabitants. What follows is a preliminary introduction to the pigmented artifacts we have found in the last three years of the Eagle Nest Canyon Expedition, as well as a partial overview of pigment and paint studies undertaken in the Lower Pecos Canyonlands.

Pigment and Paint

Paint recipes in this region are believed to be comprised of three ingredients: pigment, a binder, and an emulsifier. Pigment is the ingredient that supplies color. The binder is the vehicle for the pigment, giving paint various qualities when drying into a film on whatever canvas is chosen. The emulsifier is a suspension agent. Though it is not known with scientific certainty the exact binding and emulsifying ingredients in the rock art paints of the Lower Pecos, Dr. Carolyn Boyd’s replicative experiments with paint-making from local ingredients may point in the right direction. She successfully used red and yellow ochers as pigments, bone marrow from deer as a binder (compare to oil in oil paint), and yucca root (which contains saponins) pounded and mixed with water as an emulsifier.

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An ocher source in the West McDonnell Range of central Australia. Ocher (mineral pigment, derived from earth) is important to many native groups around the world, and it features in the native place names of several place I have lived: Death Valley, California has an indigenous name of Tumpisa (and variations of that name), which is translated as rock ocher.  Similarly, Dubbo, a country town in New South Wales, Australia, is translated as “red earth” and is said to refer to ocher used in body paint

DNA studies aiming to reveal what species of animals may have been used in making the binder in rock art in this area have been undertaken on samples from local pictographs. Unfortunately, the studies thus far have not yielded satisfactory and replicable results. On the pigment front, however, our own Charles Koenig and Amanda Castaneda, in conjunction with Carolyn Boyd, Karen Steelman, and Marvin Rowe, have made strong headway in elucidating what some of the pigments used in this region are. More on that below.

Local Rock Art Styles and Canvases

As many of readers of this blog know or have gathered by now, the Lower Pecos Canyonlands is known for its pictographs. Actually, that is quite an understatement- the region is becoming world-renowned for its pictographs. There are four defined styles of pictographs: Red Linear, Pecos River Style, Bold Line Geometric, and Red Monochrome. The styles are believed to be chronologically separated and reflect the culture of different (though perhaps related) groups of people. (For more on rock art of the Lower Pecos see http://www.texasbeyondhistory.net/pecos/art.html and check out SHUMLA’s  pioneering rock art studies).

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Amistad National Recreation Area archaeologist Jack Johnson at White Shaman, one of the classic Pecos River style pictograph sites in the Lower Pecos.

As mentioned, there are also decorated portable artifacts found in excavated contexts. These include the relatively common painted pebbles, rare painted woven items such as burial mats, and rarer-still painted faunal remain such as deer bones, mussel shell and snail shell. Paint would have been applied to other ephemeral canvases as well, such as human skin.

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An “early” style painted pebble recovered from Eagle Cave in 2015. Notice the black, fine-line design. Pebble is about 6 cm long.

Pigmented Artifacts from Eagle Nest Canyon

During the Ancient Southwest Texas project’s three years of excavation in Eagle Cave, six pigmented artifacts have been identified. Several of these have small splotches of red pigment or paint on them, such as the fire cracked rock and flake below.

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Left: FN33079, found near the center of the rockshelter in a layer dominated by fire cracked rock and ash. A piece of red ocher was found in the same strat. Right: FN33960: This piece of fire cracked rock with pigment on it was found in the same general part of site (PS016) as painted limestone below.

Other artifacts have better defined pigmentation and I believe would lend themselves to an interesting study of possible pigment and paint-making technologies. These include a tabular limestone rock with thick paint coating one surface and dripping over the edges…

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FN32916 was found in a fiber-rich (botanical) layer with excellent preservation, near the front of the rock shelter. The strat also contained coprolites, debitage, a core, flake tool, and a quid (chewed fibrous succulent leaf). The reverse side is unpigmented but appears to be pecked, as is typical of a stone surface being prepared as a grinding implement. This artifact is unusual in that it appears to be covered in opaque paint rather than just pigment.

And a second broken limestone rock with pigment along one margin.

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This limestone fragment (FN32955) was found in the same sampling column but slightly lower than FN32916 above, and seems to be the same rock type. Pigment runs along one margin, and is splotchy on the back side. It was also found in a fiber-rich layer with other artifacts, including coprolites, knotted fibers, and a burned antler fragment.

…a flake with a heavily pigmented margin….

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This chert flake with pigment along one margin was found near the back of the rockshelter in a layer with scattered fire cracked rock and charcoal. Numerous other artifacts were also found in the layer from which this artifact came, including hundreds of animal bone fragments, stone tools including a dart point, and, interestingly, a crumbly piece of ocher.

A final pigmented artifact from Eagle Cave was found as we were removing slumping and disturbed sediments from the trench floor. The artifact is unfortunately without stratigraphic provenience. It is an interesting artifact nonetheless, a broken oval mano with clear evidence of grinding on several sides. A vertical break through the ground stone artifact has edges/margins that have been trimmed or beveled all the way around the break, resulting in a raised surface. Red pigment is evident on the ground surfaces, and on the raised broken surface it appears that there is faint yellow pigment!

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The same fragment of ground stone with red pigment (left) and yellow pigment (right) collected from disturbed deposits in Eagle Cave.

Three pigmented artifacts were also found in Kelley Cave and are described by Dan Rodriguez in his 2015 thesis:

“One bifacial and one unifacial scraper were observed to have red pigment on a single side. The pigment on the bifacial scraper appears to be a congealed paint while the unifacial scraper pigment appears to be an applied powder. Also found in Feature 3 was a burned rock fragment with a red brush mark.”

Other pigmented artifacts have been found in the general region as well illustrated by the online TBH exhibit by Susan Dial on Kincaid  Shelter (see Ancient Art: Mysterious Stones and Pigments). This rockshelter located about 50 miles northeast of the Lower Pecos Canyonlands shares strikingly similar painted and incised pebble designs, as well as a number of pigmented limestone cobbles which may have been used to process pigment.

Progress in Pigment and Paint Research

With the exception of the aforementioned ground stone with likely yellow pigment, all pigmented artifacts thus far identified in Eagle Nest Canyon are pigmented red. Paint colors found in the rock art in the Lower Pecos Canyonlands are white, black, yellow, and a spectrum of reds to oranges. Past studies using X-ray diffraction (XRD) on Lower Pecos murals detected specific iron minerals in the pictographs, such as hematite. All pictographs on which XRD was conducted contained a combination of iron minerals. A recent portable X-ray florescence (pXRF) study by ASWT’s Charles Koenig and Amanda Castaneda, in conjunction with other researchers, has yielded interesting insight into what type of mineral pigments these colors are typically associated with. pXRF is a tool for analyzing elements, is non-destructive, and as the name indicates—portable! For these reasons it is a useful tool in identifying elemental similarities and differences in rock art. Koenig et al. found that manganese is the usual pigment in black paints in the Lower Pecos, though charcoal was also used. Red and yellow paints are made with iron-rich minerals, pXRF shows, but may be combined with manganese (either by a natural mixing in the ocher source or intentionally by the artist.) A result of this study was to elucidate the use of manganese in black paints in Pecos River style pictographs, and infer by the absence of manganese in black colored Red Linear style pictographs and un-typed styles, that charcoal was the pigment. Charcoal presence in pictographs also has potential for radiocarbon dating, a method which Dr. Karen Steelman, a collaborating researcher of ours, is currently exploring.

It is an exciting time to be studying Lower Pecos archaeology, as so much interest is being garnered by local research, and as we have many new technologies available which can help us better understand our human past. I feel that we are on the brink of linking the rock art on the walls to the archaeology in the ground, and it will be fascinating to better understand the relationship these pigmented artifacts had to the rock art created here.

Zone VI: Into the Eagle Cave Unknown

Zone VI: Into the Eagle Cave Unknown

By Charles Koenig

Since we began excavating the main trench in Eagle Cave in 2014, we have always had some idea of what to expect thanks to the previous work by the 1963 University of Texas excavations.  In 1963, Mark Parsons and Richard Ross spent three days illustrating the north wall of the “Old Witte Trench.”

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Digitized and colorized field illustration of the 1963 Eagle Cave profile drawn by Mark Parsons and Richard Ross. The deep column in the center was added several months after the upper profile was annotated. Many more lenses, layers, and levels were noted on this profile than made it into the simplified, published version below. Original scan courtesy of the Texas Archeological Research Laboratory.

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Version of the profile that appeared in Ross’s 1965 Eagle Cave report. Only the major stratigraphic zones are noted.

Even though they did not record nearly as many “zones” and “lenses” as we have documented strats (units of stratification), we can correlate some of the 1963 stratigraphic zones to 2015/2016 strats because they took the time to illustrate and describe the different layers. Broadly speaking, UT recorded 6 major stratigraphic zones (1-6), in addition to many other lenses and layers within zones. In Zones 1-5, UT recovered a variety of cultural debris (chipped-stone tools, plant and animal remains, and our favorite – burned rock), and the earliest deposits in Zone 5 were dated to 6500-7000 B.C. (Ross 1965). However, they stopped excavating at the top of Zone 6 because it was considered a “sterile layer of yellowish limestone spalls and dust.”

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One of the 1963 Eagle Cave crew members beginning to dig the deep test through “sterile” fill. The white sediment at the man’s feet is Zone 6. View is looking west. Image courtesy Texas Archeological Research Laboratory.

From the outset of our work in Eagle, we have been guardedly optimistic the deposits from Zone 6 and deeper might not be sterile, but simply UT did not excavate far enough to find the next layer of cultural material. In reading the site journal for the 1963 work, we realized the UT crew stopped excavating at Zone 6 not only because they interpreted it as being sterile, but also because they simply ran out of time to excavate any deeper. They did sink a deep test to bedrock at the end of their work, but this was quickly excavated, and from what we can gather, they did no detailed recording or screening of materials that came out of this test. So, as we began excavating into the top of Zone 6 at the end of our last session (the last week in March) we were excited because we knew from that point down we would be excavating into the unknown – the oldest (>9000 years), minimally explored deposits within Eagle.

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South trench in Eagle Cave profile as of 4/17/2016. Top image is just of the orthophoto of the trench, and the bottom is the same image superimposed with our interpretation of UT Zones 1-6 .

First Contact

The first place we excavated into Zone 6 was towards the rear wall in the site. Several of us (Kelton, Justin, and myself) were excavating units to expose a profile section, when Justin uncovered a most surprising artifact: a thick fragment of what appeared to be bison long bone.

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Justin working in Zone 6 (white/yellow in profile).

In addition to the bison bone fragment, Justin also recovered two chunky biface fragments. After the months of anticipation, wondering what we may or may not find, and then to find artifacts and bison bone in one of our first units … we were excited, to put it mildly! As most things go on an archaeological site the bison bone find occurred on almost the last day of the field session, so we had to wait two full weeks before we could investigate Zone 6 again.

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The two biface fragments (top) and sizable bison bone fragment (bottom) recovered in Zone 6 towards the rear wall.

The Trench Floor

Even though we all wanted to jump right in to excavating Zone 6 and seeing what was there, the first thing we did when we got back to work was to devote several days to removing disturbed fill from the bottom of the trench. After completing this dusty, hot, exhausting job we had exposed intact stratigraphy across the entire bottom of the trench. And, by removing the disturbed fill, we exposed more or less exactly the floor of the 1963 excavations into Zone 6.

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The crew removing disturbed fill from the bottom of the trench (left), and the top of Zone 6 exposed in the bottom of the trench (right).

Once we had the top of Zone 6 exposed across the trench floor, we laid out several units with the goal of excavating down in the trench floor to give us room to work as well as expose profiles on the south wall. However, after only excavating about 10 centimeters below where the UT excavations stopped our excavations slowed dramatically when we started finding bison bone fragments; lots of them.

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The scatter of bison bones as originally photographed in Unit 109.

Unlike the single bone fragment Justin found in the upper Zone 6 towards the rear of the site, Emily, Spencer, and Bryan began exposing dozens of fractured bison bones scattered over a 5 meter area. We knew we had something really cool, and that Zone 6 was definitely not sterile!

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The top surface of Feature 14 (fragmented bison bone scatter) as initially exposed in the Eagle Cave trench floor. The bison bones are slightly more yellow than the surrounding white/yellow rockshelter sediments.

Feature 14

As we continued to expose more and more bone, we realized these bone fragments were all related to one another and likely represent a single behavioral episode. Because of our working interpretation that the bones were fractured and strewn across the extant surface of the shelter in a single event, we gave the bone scatter the designation Feature 14 (the 14th formally designated feature recorded in Eagle Cave since 2014). The feature designation also means we wanted to take special care in how we went about recording the provenience of the bones. To do this we took a series of SfM models and shot in with the TDS many of the bones.

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Intermediate map showing Units 108 and 114 with additional bison bones exposed.

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Intermediate map showing Units 109 and 115 with additional bones exposed. The cluster of rock in the center of the image is Feature 15, a likely hot-rock thermal feature.

We were also very fortunate to have Art Tawater on hand that week as one of our volunteers. Art is a longtime member of the Texas Archeological Society and the Tarrant County Archeological Society, and one of his passions and areas of expertise is zooarchaeology. After the bones were mapped in (piece-plotted with TDS shots) and photographed, Art made a preliminary field ID for the various bones. This was a huge help because none of us (except Black) had any experience with excavating bison bones, let alone trying to figure out what element each bone fragment might be from!

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Art (left) helping Spencer (right) ID and package up bison bone for transport out of the site.

Mapping in the bones and collecting field observations slowed down the removal process, but we wanted to collect as much data in the field as we could so that when our collaborating zooarchaeologists Chris Jurgens and Haley Rush finally get to see the bones they will be well armed for the analysis to begin!  Plus, while the bones were well preserved, they had been purposefully fragmented originally  and some were crushed and cracked by the overlying deposits and did not remain intact upon careful removal.   Our detailed photographic record and Art’s field observations will allow a more complete analysis of the butchering and processing activities that took place on this surface over 9,000 years ago.

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One of the few diagnostic bones we recovered: a proximal left mandible (jaw) fragment from a juvenile bison with deep cut marks on the posterior side. This bone is visible in the Unit 109-115 image above.

Not Just Bone

In addition to the scattering of bison bone, we also found a modest amount of associated lithic debitage and stone tools. If you look closely several of the tools are visible in the above maps. It is telling that most of the chert artifacts appear to be made of only two or three cobbles judging from the matching colors and textures.  This bespeaks a short-term occupation during which only a few cobbles were knapped.

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Two bifacial tools found in direct association with the bison bone of Feature 14. Some of the debitage recovered appears to be the same raw material.

And although there is not the dense concentration of fiber within Feature 14 as in other areas of Eagle, we did recover some very badly decomposing organics.

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A decomposing piece of wood recovered during excavation of Feature 14.

And I also can’t forget to mention the possible hot-rock thermal feature (Feature 15) found at the east edge of the bison scatter, with bones above and below rocks that appear burned!

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Chalkboard shot of Feature 15, a likely hot-rock thermal feature in direct association with the scattered bison bones.

So What Does it All Mean?

We just finished excavating the main portion of Feature 14 earlier this week, so it is really too early to even say the analysis has begun, but we can at least offer up some of our preliminary observations and working ideas. Based on the how fragmented the bones are, we hypothesize Feature 14 represents a bison butchering and processing locale/event within Eagle Cave; possibly that of a single juvenile bison (portions thereof).

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The outline of all mapped bison bones (in black) superimposed onto the initial Feature 14 exposure. The most complete bone–a rib–was recovered at the boundary between Units 114 and 109. All the other bones are fragmentary.

Not only were most of the bones fragmentary, but very few had diagnostic (articular) ends left. In most cases, the field ID was either “medial rib fragment” (~90% of bones) or “long bone shaft fragment” (~8%) of the bones. The fragmented nature of the bones suggests that the people may have been trying to extract bone marrow or render grease from the bones after the meat was removed.

We also have some interesting horizontal distributions of certain artifacts and bones. The areas where we found the highest number of bones with cut marks overlaps with where most of the debitage is clustered. Bones with cut marks plus many flakes indicates this location was where people were cutting bone and/or meat and needing to resharpen their tools. It was also telling to find the relatively few burned bone fragments we found appear to have been concentrated around several thermally altered rocks and scattered charcoal!

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Distribution/highest concentrations of burned bone, bones with cut marks, and debitage overlaid against the bone scatter.

We were also fortunate to recover a projectile point from the same layer as the bison bone. Although not directly associated, this dart point fragment was recovered just to the west of the majority of the bison bones and is made of a very similar dark chert material as much of the debitage.

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From top left: photograph of dart point fragment in situ; both sides of the dart point in the lab; map showing the location where the dart point was recovered in relation to the bison bone.

At the moment we are not ready to officially type the point, but it is a lanceolate, contracting stem dart point fragment that shares several attributes of Angostura points.

Where to from Here?

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Myself, Jack Skiles, and Steve ponder Feature 14 when it was first exposed.

The fact that we encountered Feature 14 as quickly as we did after beginning into the “sterile” deposits of Eagle Cave gives us hope for additional, older, cultural deposits below. We do not know how old the bison bones are at the moment, but we will be sending out radiocarbon samples soon. We have had a lot of fun excavating this intriguing feature, and we look forward to sharing new findings as we make them!

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The location of the Feature 14 bone scatter (linear cluster of yellow dots) and the original bison long bone fragment discovered towards the rear wall. We are excited by the prospects of what we may find as we go deeper into unknown Eagle Cave!

The Next Layer, A Sampling Column Story

The Next Layer, A Sampling Column Story

By Kelton Meyer

The inherently destructive process of excavation means that archaeologists must devise effective measures to capture as much useful data as possible as deposits are destroyed. One of the most important aspects of our excavations in Eagle Cave is the process by which we sample intact stratigraphy. By carefully exposing intact layers in profile, spending much needed time defining strats and sampling with diligence, we are able to gain high resolution views into the lives of the prehistoric Native Americans who frequented Eagle Cave.

I’m Kelton Meyer, an intern with the ASWT project and soon-to-be graduate student at Colorado State University. I’m writing this post to share my experience in excavating Profile Section 25 (PS025), and to take you into the trench where we are working hard to tell Eagle Cave’s stratigraphic story.

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Excavating my sampling column, PS025

Exposing Profile Section 25

The first step in the process of sampling intact stratigraphy is to create a clean profile to clearly expose the layering. We do this by excavating in fairly traditional excavation units to create a “wall” (AKA profile) in an undisturbed context. In the case of PS025, two units were excavated to create the profile, Units 76 and 85. The unit configurations are not necessarily governed by size, shape, or grid orientation, but are dependent on identifying the dividing line between intact and disturbed deposits. When we first started excavating in the main trench last spring, we had to remove lots of disturbed fill from the face of the trench prior to placing an excavation unit. However, as we have continued deeper this season, we have been able to trace the intact deposits easier and more confidently as we have worked our way down into the trench.

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Unit 76 (left) excavated in May 2015 and Unit 85 excavated in February 2016. The south walls of these two units combine to create PS025.

Our excavation units typically consist of anywhere from 1-10 layers, and these layers are defined by factors like changes in sediment color, consistency, artifact density, or the indication of a possible cultural feature. Without a profile to guide our excavation, it is often very difficult to excavate these layers following natural stratigraphy. To aid us in assigning stratigraphic provenience to any artifacts, we take sets of SfM photos (see Archaeology in a Whole New Dimension)  to build 3D models of our units each night in our digital field lab. Using these 3D models we can link our “traditional” units with the stratigraphy we record in profile. Once the necessary excavation units have been completed the newly created profile wall is ready for cleaning, SfM photogrammetry, and field annotations.

Profile Section 25

PS025 is one of the larger profiles, located towards the rear of the rockshelter and in the approximate middle of the overall vertical stratigraphy of the site. It is representative of different occupational zones, and varying episodes of earth oven dismantling and refuse.

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An orthomosaic of the south trench and profile sections with PS025 highlighted in red.

 

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Orthomosaic of Profile Section 25

What We Can See

After we’ve built a 3D model of the profile in the lab we print out an orthomosaic (a profile view) into the field for annotation. With a conveniently sized paper copy of the profile in hand, we can sketch stratigraphic changes, assign numbers to the strats, and take any other notes that we deem necessary. For PS025, the field copy was especially handy due to the varying effects of sunlight upon the lightly colored sediment, and the broken characteristics of the strats.  Once again, the Eagle Cave stratigraphy bears little resemblance to textbook layer cake simplicity.

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My PS025 field annotation.  The numerous hatchered areas are rodent bioturbated.

When determining stratigraphic changes in profile, several factors are taken into consideration. We first identify any visible disturbed contexts, such as rodent burrows. In  PS025, evidence of rodent bioturbation was obvious. Large pockets of mottled sediment intruded into most of the intact stratigraphic layers (strats), bringing fecal matter, grasses, and other debris into the profile wall. We then assign strats from top to bottom,  according to the superposition of the layers. Strats can vary in color, texture, and consistency of sediment. Some strats extend across fairly large zones, while others are small, thin, and broken in profile view. Once the profile has been fully annotated and the strat information has been entered into the database, each individual strat is ready for direct sampling.

I found the annotation of PS025 to be an enjoyable experience, and it allowed for some artistic expression. Bioturbation often presents annotation challenge, but it sharpened my archaeological skills as I traced and separated the intact from the disturbed.

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Here I am concentrating on my profile annotation

Taking from the Wall

In Eagle Cave it is important to record the provenience of all aspects in excavation, and especially in sampling. A midpoint for each strat is “shot in” using a TDS (Total Data Station) and the precise location of each subsequent sample we take from the profile must also be shot in as well. We collect spot samples, geo-matrix samples, and 14C samples. A spot sample is a small bag of undisturbed strat sediment. A geo-matrix sample is a somewhat larger bag of sediment that includes rock and pebble constituents to allow the geoarchaeologists to characterize sediment size and texture.  A 14C sample can be a collective variety of botanical remains like charcoal, seeds, or leaves that come from unquestionably intact areas within each strat. These point-provenienced samples will allow the analytical team to review sediment characteristics, analyze the geo-archaeological properties of individual strat matrix, and, potentially, to obtain a targeted date from each strat.

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TDS points of all samples and strat definitions taken from PS025

The collection process from the wall requires expert troweling and methodical strategy. A reduction in the size of trowels, pans, and brushes is absolutely necessary! When choosing to collect samples from a profile, it is best to begin from the bottom and move upwards so that the next strat is not contaminated by sediment spills. Sometimes, the strats in profile are so small or intermittent that it is not possible to collect all three sample types. Priority is given to spot samples where adequately sized geo-matrix sampling is not possible, and 14C samples are collected when the appropriate material is visible in the profile (e.g., a charred cut leaf base). Additionally, artifacts that have been left in situ  as the profile wall is cleaned and examined are shot in, photographed, and collected. When samples of each strat have been removed, it is time to choose where to place a sampling column.

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Collecting samples from the profile

Collecting from PS025 was at first a heartbreaking experience. Much time was expended in making the wall an appealing example of visual stratigraphy.  I’m trying to say it was tedious work and often frustrating when seemingly intact proved to be rodent-churned. However, understanding the importance of the samples I was taking made it all worthwhile.

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Distal portion of a chert biface in profile

The Sampling Column

A sampling column is a specific type of unit used in our excavations at Eagle Cave. The principle goal of these units is to provide an in-depth look into the stratigraphy of a profile section by isolating intact strats and collecting sizable matrix samples. Choosing where to place sampling columns depends entirely on the characteristics of individual profiles and factors like stratigraphic density, artifact density, feature locations, etc. The evolving research goals of the project dictate where columns are placed. Eagle Cave field director Charles Koenig consults with the excavator(s) most familiar with each profile section and makes the call. Sampling columns may be placed in areas of the profile that favor exposed features, and this may result in some relatively minor strats not being sampled. This is why it is important to collect the initial samples before the sampling column is placed! Some profile sections receive more than one sampling column, for instance exposures with nicely intact stratigraphy and excellent organic preservation like latrine deposits.

The columns are typically small rectangular areas measuring 20 to 40 cm in each dimension.  Sampling columns are excavated strat by strat, and in the more dense stratigraphic areas of the site they can be consist of 20 plus strats. The proper excavation of a sampling column is very detailed and careful work. All of the undisturbed strat matrix is collected for later processing and curation, and all artifacts encountered during excavation are shot in, photographed, and collected. Additionally, we carryout Rock Sort data collection for each strat. The crew must constantly refer to their field annotations to ensure that the excavated strat layers do not cut into new strats, or involve previously sampled strats as sediment is removed.

At the end of each completed strat, SfM photogrammetry is performed. In many cases, new stratigraphic layers are encountered and identified as the sampling column comes down in the profile. These new strats must be annotated, sampled, plotted, and collected. Sometimes, strats that existed in profile may not continue far behind the profile wall, and thus must be sampled even more carefully to preserve at least some data given the paucity of sediment matrix.

The column for PS025 was strategically placed to sample a feature visible in profile.  The defining characteristics of Feature 11 were the large boulder-like burned rock protruding from the wall and the surrounding pattern of compacted ash, charcoal, and fire-cracked rock. In total, the sampling column consisted of 14 excavated strats, with one being identified mid-excavation. Most of the strats consisted of ashy gray/white sediment having a very fine texture and containing compacted charcoal.  Some strats produced burned and unburned fiber, other botanical remains (e.g., charred seeds), animal bone, chipped stone tools, and other types of artifacts shot in with the TDS.

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Location of sampling column

 

Lab Processing

After each strat is sampled and collected, matrix is brought back to the field lab for processing. The collected matrix from each strat is weighed and quantified, and then screened through a 1/2” sieve to remove large artifacts and rocks. Artifacts collected from the screen are cleaned, weighed, analyzed, and set aside for curation. The remainder of the matrix is bagged and cataloged, awaiting further analysis. The screened matrix is also curated and given a specimen number for our database, so that the provenience of each sample is thoroughly recorded in our system.

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Justin Ayers sieving dusty matrix

As work continues in Eagle Cave and more data is collected, the process of curation becomes increasingly important. The variety of artifacts and samples we collect will provide answers to many of our research questions regarding the lifeways of the prehistoric occupants of Eagle Cave. Samples for macrobotanical data, faunal identification, lithic reduction strategies, tool analysis, archaeoentomology of human fecal matter, and even phytoliths, are awaiting for the analytical team to decipher as we work towards understanding natural and cultural formation processes, ecology, climatic conditions, cultural patterns and much more from this awe-inspiring rockshelter in the Lower Pecos Canyonlands.  I’m proud to be able to contribute the next layer in the Eagle Cave sampling column story.

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Elton Prewitt and I examine an artifact I exposed while excavating my sampling column.

Experimental Gauntlet: Replicate This!

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“Butted knife”  41VV2239  FN50156

By Steve Black

As the principal investigator of Ancient Southwest Texas (ASWT) and as faculty sponsor of the Texas State Experimental Archaeology Club, I hereby challenge the 2016 ASWT crew and Club members to convincingly replicate the use wear pattern(s) apparent on the recently recovered biface pictured above.

This distinctive artifact was found in situ on 3/28/2016 at Sayles Adobe (41VV2239) by ASWT 2016 Intern Kelton Meyer working under Victoria Pagano who is directing the Sayles investigation for her thesis research. The artifact was found about a meter below the surface of this terrace site amid scattered FCR (fire-cracked rocks) that I would guess represent the upper and outer part of an earth oven facility where desert succulents like sotol and lechuguilla were baked. (It could be the edge of a buried burned rock midden, perhaps an incipient one?)

In our previous six seasons in the Lower Pecos Canyonlands (LPC), ASWT has found no other example of this quite formal artifact type, but several were found during the Amistad salvage era at the Nopal Terrace and Devil’s Mouth sites.  They occur fairly often in the Kerrville area and in the western Balcones Canyonlands.

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What kind of a “fist axe” would have such a delicate blade, a butter axe?

These unusual artifacts have been given many names.  What is in a name? Some have called them fist axes or hand axes because of their somewhat similar appearance to Old World artifacts, most of which date tens or hundreds of thousands of years earlier.  There is a simple morphological reason why these Old World terms seem functionally inappropriate – what kind of axe would have such a delicate cutting edge? (A butter axe?)  The latest edition of Turner and Hester (but cf. earlier editions) uses the type name Kerrville biface, which is geographically appropriate, if dissatisfying to some. Typological maven Elton Prewitt prefers the descriptively appropriate term butted biface. I prefer the functionally appropriate term butted knife; that these are some sort of cutting/slicing tool seems obvious.  Consensus, however, has yet to emerge on either the name or the specific purpose(s) of these tools.

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Even though I pride myself on not being “artifact-oriented,” this unexpected new find in excellent context has me in a dither. When I initially looked at the artifact in our field lab the evening it was found, it set my intellectual juices flowing and I harkened back several decades ago.  Then, as is still true, I was convinced that I knew exactly what butted knives were characteristically used as: sotol trimming knives (plus Agave lechuguilla in Lower Pecos?).

I recall that I once envisioned experimentally replicating the striking use wear that most butted knives display:  remarkably bright “silica polish” rather evenly distributed across both faces of almost the entire blade of intact examples. I even took several modest steps in the experimental direction.  For instance, Glenn Goode kindly made a fine replica to be used experimentally.  But alas, I failed to follow through with the hard work that a rigorous replication project would entail and my Goode-made biface sits gathering dust in my TxState office on my show-and-tell shelf.

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Butted biface replica made by Glenn Goode out of Georgetown flint.

Within an hour of seeing the Sayles Adobe specimen, I took several pictures of it and sent one to my former mentor and long-time boss, Dr. Thomas R. Hester, UT-Austin professor emeritus and former director of both the Texas Archeological Research Laboratory at UT-Austin and the Center for Archaeological Research at UTSA.  I also sent one to Elton, who most of us Texan archaeologists regard as a stone-tool typological guru of the first water (most of us think the same about Tom Hester). The subject line of my email was “Butted agave knife” and I closed both email messages with “I knew you would appreciate!”  Sure enough, they both replied right away and here are tidbits.

Hester:  “We call them Kerrville “bifaces” because the polish/wear has never been satisfactorily replicated.  But, I’ve long thought they were plant-working tools, not necessarily slicing and dicing, but mebbe chopping/hacking into an agave or some other soft plant where the distal got “imbedded” and the polish eventually appeared.”

Prewitt: “Nice butted biface. I do not like the term “Kerrville Biface” since it has never been appropriately defined as far as I am aware (I could very well be wrong, but …). And, yes, we do have good ideas about their uses.”

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These are called “butted” because the thick, proximal end of the tool is typically the outer cortex-covered surface of the original chert nodule. It was obviously made this way so the usually rounded butt fits in your hand with the blade tip (distal end) pointing out ready for action. The Sayles Adobe artifact seems to lean to the right in this photo because it is resting on its rather flat butt.  This artifact appears to be made on ledge chert, thus the flat, thin cortex rind you can glimpse.  High quality ledge chert is rare in the Lower Pecos, but often occurs in  in the Kerrville area.

Intrigued?  So here is my challenge.  I think it would be a most worthy project to (1) design a rigorous experimental program to convincingly replicate the telling use wear pattern(s) of a call-it-what-you-will; and (2) successfully follow through with such a program.  Here are some considerations and suggestions.

Before picking up the gauntlet, you will want to do your homework and do your best to read everything ever written about the subject.  These butted things have been admired by many, often speculated and reasoned about in print, studied under the microscope, and studied experimentally (if inconclusively). Doubtlessly more so than I can recall.

This will not be easy.  If the use wear could have been easily and convincingly replicated it would have already been done. And it is entirely possible these artifacts were sometimes used on more than one material and/or in more than one motion. I venture to say that such a project will almost certainly take many months of concerted replicative effort and likely several years to see through to peer-reviewed publication, which should be the end goal.

With that in mind, I recommend that the ASWT crew and the Club talk amongst yourselves and consider forming a leadership team of three to guide the effort.  You will need competent, motivated decision makers and with three, you would always have a tie-breaker (as Dan Potter, Kevin Jolly and I learned on the Higgins Experiment in 1993).  And you will need diverse skills and continuity.  I recommend that the three project leaders include TxState students or former students of varying levels of experience including several who aren’t graduating anytime soon.

But it will likely take far more than three of you to get it done.  You will likely want to try more than one contact material (sotol/lechuguilla, meat, and grass all come to mind).  You will likely need many hundreds of strokes in said materials to create patterned wear.  You will want to properly document each step, photographically, metrically, and so on.  I’d think it would make a fine experimental project.

You would be wise to consult others.  I would put Professor Hester at the top of your list.  I’ll bet he has seen more than one student paper on the subject, he has sure as heck seen many more of things than me, he has published on them, and I know he shares my abiding curiosity.  Elton is always a go-to source for informed typological opinion regarding lithics.   Professor Britt Bousman teaches the graduate seminar in lithic technology at TxState, and he might even let you look at and document butted things (perhaps before and after replication?) using TxState’s fancy use wear microscope. Dr. Mike Collins of TxState is unsurpassed in his knowledge of lithic technology and he once dug a site near Kerrville.  Dr. Marilyn Shoberg (of Austin) might well have looked at some of these things under a scope. Dr. Todd Alhman might have archaeological examples at CAS (ask about the Tom Miller Collection).  Chris Ringstaff or Glenn Goode might be willing to make several freshly chipped stone replicas to be used in experiments.  Ken Lawrence would certainly approve of experimental work of this sort being done out at Professor Grady Early’s place in the phosphate-sampled area.  I’m certain inquiry will lead you to others who would be worth consulting and might lend a hand.

But do not make the common mistake of uncritically accepting dogma.  Challenge assumption, question authority, and think for yourselves.  I, for one, could well be wrong about some of my claims in this piece as well as those I make in classes and in print. (Say it ain’t so, Shoeless Blackie, say it ain’t so.)

Should a group of you rise to the occasion and accept the challenge, don’t do so lightly.  I won’t hold it against you if you don’t pick up the gauntlet.  But I might if you accept the challenge and fail to follow through.  If I’ve piqued your interest, start with doing your homework and decide whether to go forward.  Then craft a proper research design.  If I approve your plan I will endeavor to support your effort in multiple ways. I think this could be fun learning exercise and make a useful contribution to Texas archaeology.

Yours in the experimental cause, SLB

Dating Eagle Cave

As followers of this blog know well, the Ancient Southwest Texas research team has been investigating this Eagle Nest Canyon and Eagle Cave since 2013.   Following a cutting-edge “High Resolution, Low Impact” excavation strategy, we have carefully exposed, documented, and sampled literally hundreds of stratigraphic layers at Eagle Cave, some pencil-thin and some thick and massive.  The deposits in this dry rockshelter are complex – nothing like the flat, layer-cake examples found in archaeology textbooks.

Instead we encounter twisting and turning layer upon layer often cutting through one another.  This intricate layering is the result of daily life in the shelter on and off over thousands of years as the ancient inhabitants dug cooking pits, baked desert plants in earth-covered ovens, and carried out myriad other activities.  They often used their abandoned cooking pits as convenient trash dumps where spent cooking debris, worn-out fiber sandals, fire-cracked cooking rocks, and much more were discarded. The Eagle Cave deposits may be complicated, but the preservation is incredible, and we are recovering an amazing variety of scientific data from uncharred plant remains, wooden artifacts, and woven mats to animal bones, insects and human coprolites.

To allow us to properly and thoroughly date the Eagle Cave deposits and critical analytic samples, we have embarked on a crowdfunding campaign and are Texas State University’s inaugural guinea pig.  Most of this post is taken from our Dating Eagle Cave campaign page.  Check it out and be sure and see the video as you consider helping support our goal of making Eagle Cave the best dated and most thoroughly studied site in the Lower Pecos Canyonlands of southwest Texas.

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Eagle Cave Main Trench Section as it looked at end of 2015 season showing mid-points of calibrated radiocarbon dates (yellow) and lots of questions about as-yet undated deposits.

Eagle Cave Challenge

The last major excavation of a dry rockshelter in the Lower Pecos Canyonlands took place back in the 1970s, when archaeologists from Texas A&M investigated Hinds Cave about 10 miles from here.  The ecologically oriented Hinds Cave dig recovered hundreds of coprolites which have been studied by graduate students and specialists ever since.  Truly, Hinds Cave has proven to be a scientific treasure (see http://www.texasbeyondhistory.net/hinds/.  We believe that Eagle Cave has the potential to build on and expand this legacy in many important ways.  Herein lies the challenge.

Major archaeological investigations of dry rockshelters with outstanding organic preservation, like Hinds and Eagle Caves, take many years of concerted research effort.  The actual digging is completed in a few years, but thoroughly analyzing the resulting data and fully realizing its scientific potential takes considerable research time and funding.  And it takes numerous carbon-dated, stratigraphically controlled samples.   We have already collected many more samples at Eagle Cave than were obtained at Hinds Cave and we have much better scientific control.

Because we are taking advantage of 21st century digital technologies, our documentation system at Eagle Cave is sophisticated and precise.  Every sample is assigned a unique code linked to a database that tells us precisely where it came from, usually within a few centimeters.  For every surface we expose – horizontal and vertical – we systematically take dozens of overlapping photograph.  Each night in our digital field lab we use special software to “stitch” these images together to form seamless three-dimensional models.  In other words, we can digitally reconstruct almost everything we excavate.  Scientifically speaking, this makes our samples extremely valuable.

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UT-North profiles from 2014 excavations being studied by Tina Nielsen for her M.A. thesis. In yellow are the calibrated midpoints of radiocarbon dates we obtained last year and the red question marks highlight yet-to-be dated areas.

Radiocarbon Dating

For us to achieve the scientific potential of such materials we must precisely date the Eagle Cave layers and special samples. Knowing exactly where something came from and what it was found with is only part of the challenge – we also need excellent chronological control – how long ago was a given layer created?  To figure this out, archaeologists use a combination of understanding the stratigraphy (layering), formation processes (how layers formed), and (radio)carbon dating (how old it is).  Any organic material can be used for carbon dating, and Eagle Cave has an abundance of organic material in virtually all of the layers. We prefer to date plant remains: charred wood, uncharred plant leaves, seeds, fiber artifacts and so on.   Using modern radiocarbon dating techniques all that is needed is a very small sample.  Specially equipped labs can measure the ratio of carbon isotopes, and calculate age based on the ratio of carbon-12 to radioactive carbon-14 (which has a half-life of 5730 years).  Do the math, and you can determine about how long ago the once-living plants died and ceased to accumulate carbon-14.

To confidently date a site with complex stratitgraphy, many dates are needed.  For instance, over fifty radiocarbon dates have been obtained on samples from Hinds Cave.  Thus far we have less than half that many for Eagle Cave. This isn’t a matter of one-upmanship, it’s a matter of scientific need.  We must know the absolute dates of key stratigraphic layers and critical samples through a concerted, multiphase program of radiocarbon dating in order to make our hundreds of samples scientifically valuable.  Securely dating key layers will in turn give us approximate (relative) dates for the many more “in between” layers.

What We Need

So far we have 18 radiocarbon dates from our 2014-2015 work.  For the next phase of dating we are seeking funding for 20 more dates.  Dating a complex site like Eagle Cave is an “iterative” process, meaning that the results from one round of dating helps us see the gaps and fine-tune the next round.  Radiocarbon dating is expensive with the going commercial rate for the most precise dating method (AMS dating) is $600 per sample.  Fortunately, we are working with a radiocarbon scientist at another university in a collaborative arrangement that allows us to get dates for less than half that rate.  Add in the need to get expert identification of the plant remains we are dating and 20 more dates will cost us about $300 each for a total of $6000, our campaign goal.  If we are very fortunate and exceed our goal, we will be able to get started on the following phase.

 Please consider helping to support our Dating Eagle Cave campaign!

 

Journey to the Center of Sayles

By Justin Ayers

Howdy! Justin Ayers here, excited to explain the ongoing bucket auger testing at Sayles Adobe. You may ask what exactly is an auger? The auger is a simple but effective tool for collecting/sampling sediment below the surface without opening excavation units. It is comprised of a lengthy pole with a helical bit (and cylindrical bucket) at the end, which is designed to twist through the earth easily, while the bucket simultaneously collects the sediment displaced by the twisting bit. After one and a half turns of the auger handle, the auger bucket is filled with compressed dirt, and the device is gently pulled up out of the hole and the bucket load is dumped into a screen, examined, and recorded. The process is repeated over and over up to a depth of 3 meters (about 10 feet!).

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Me and the auger.

Conducting a bucket auger survey of Sayles is important because it is allowing us to relatively quickly sample the stratigraphy across the terrace, a task that would take months to accomplish using hand excavation units. Further, by combining the different sets of auger data we are able to map out the subsurface deposits (both natural and cultural) of Sayles. These data will contribute to Tori Pagano’s ongoing thesis research (see Tales of Sayles Adobe), as she aims to define and sample the natural and cultural deposits of the terrace.

Bucket Auger Process

Tori’s plan is to build on the ground-penetrating radar (GPR) survey conducted at the site in January by Tiffany Osburn. We wanted to follow the GPR grid with our bucket augering as closely as possible so we could investigate several interesting radar anomalies seen at certain locations and depths within the terrace.  Happily, our collaborator geoarchaeologist Ken Lawrence kindly allowed us to borrow his bucket auger!

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East-west GPR transect (top) and west-east transect (bottom). The yellow arrows point to the same anomaly in both transects, indicated by the upside-down V-shape.  This anomaly is approximately 1 meter (~3 feet) below the ground surface. These are the types of anomalies we wanted to hit with the auger testing.

 

We wanted to use the bucket auger tests to begin to “ground-truth” the GPR anomalies (i.e., determine what the anomalies are caused by).  We also wanted to compare the sediment sampled by the auger to the exposed stratigraphy in the “Borrow Pit” excavation area.  The auger testing is showing us that the stratigraphy of Sayles Adobe is more complex (and interesting) than that seen so far in our initial excavation exposure in the Borrow Pit.

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You can see the bucket auger on the left, leaning against a tree. To the right you can see the rest of the equipment  we used during auger testing: Munsell color chart, 2mm geologic sieve, 5-gallon bucket, and lots of recording forms!

Augering Procedures

Step 1: Stake out targeted locations of auger columns.

  • Transect sampling intervals – 4 meters apart
  • Shoot in surface points with TDS (Total Data Station)
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Plan map of Sayles Adobe showing east-west bucket auger transect. The red dots are the auger tests (laid out 4 meters apart) that have been completed thus far.

Step 2: Begin sampling

  • The auger excavates a 10cm diameter hole, and each bucket full of dirt is ~8cm deep. Once a bucket of sediment is collected, the auger is pulled up to the surface.
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From left to right: auger in the hole, removing the auger, the auger fully out of the ground, and finally dumping the sediment into the sieve.

Step 3: Sieve the sediment.

  • Once the bucket is pulled out of the auger hole, it is dumped into a 2mm sieve. Only the fine sand/silt mixture will pass through the screen, leaving snail shells, roots, FCR (Fire-Cracked Rock), and debitage on the screen.
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Dumping the sediment into the sieve. The bucket auger bit is clearly visible.

Step 4: Documentation

  • A metric tape (or “pocket stadia”) is used to measure the depth of the hole after each bucket auger sample was removed. This allows us to monitor our progress and make the auger data comparable from one auger column to the next.
  • The sediment texture varies from a fine sand to a compact clay-silt.
  • Color is recorded using a Musell color chart. We found that the 10YR color sheet works best for us.
  • Lastly, general notes are made of the sediment, e.g., organic materials if present, FCR, charcoal, & ped toughness (Wikipedia: ped = a unit of soil structure such as an aggregate, … block, or granule, formed by natural processes.)

Step 5: Homogenize and Sample

The sediment that falls through the screen is homogenized (stirred around) in the bucket before we collect a small representative sample. After the field season Tori, under the tutelage of geoarchaeologists Dr. Charles Frederick and Ken Lawrence, will process the samples to determine grain size and test for magnetic susceptibility (among other things). Tori plans to use the auger column data to create composite stratigraphic profiles (sections) across the terrace that will be integrated with GPR and other lines of evidence.

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A “cube” from the auger testing of Sayles Adobe awaiting further geoarchaeological analysis.

I should note that while the bucket auger does its job very well, it mixes the sediment in each bucket load together such that thin layers only a few cm thick are hard to detect.  And even though we are careful to insert and remove the auger gently, inevitably there is some admixture of sediment from the walls of the hole.  In other words, we end up with somewhat averaged samples in 8cm increments. We homogenize each sample to make sure it truly represents an average of each increment. By carrying out each auger test in exactly the same systematic way,  we can compare apples to apples with our auger samples and differentiate significant stratigraphic changes.

Luckily Sayles Adobe has very nice silty and sandy deposits (as opposed to compact clay or gravel) and testing has gone without a hitch … for the most part. Sometimes we are impeded by rocks and roots, forcing us to move our auger test column to a new location. If we encounter something hard that we can’t get through, we simply move the auger hole 30-40cm over from the original location and try again. Overall, we able to get down to the full 3-meter depth in only about 50% of our tests. In the other half we are stopped by burned rocks or other obstructions (like large mesquite roots) before reaching maximum depth.

What Are We Finding?

Based on our initial excavation in the Borrow Pit area along with the GPR survey findings, we suspected that we would hit the upper mud drape (I will explain why I say “upper” in a bit) around the same depth at multiple points on the terrace (see below profile of the Borrow Pit in Sayles).

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The east profile of the “Borrow Pit” in Sayles. The “upper” mud drape is noted as S003,  just to the left of the orange tag.

So far we have found that the mud drape is not a perfectly flat horizontal layer, it tends to follow the topography of the deposits it covers. What I mean is that in places there may have been exposed rocks or humps in the ground that the mud drape settled over during the flood event, which may be the AD 1340 flood that we documented at nearby Skiles Shelter and Kelley Cave.  Many (all?) of these rocks are FCR that were capped by the mud drape. The upper mud drape is thin and hard (clay-silt), compared to the fine sand and sandy silt that makes up the majority of the site’s deposits. In essence, the mud drape seals the cultural material that lies beneath it. 

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Bryan standing in the “Sandbox” area at Sayles looking at FCR that he is just beginning to expoose. The mud drape in this unit (denoted by yellow arrow) is very thin compared to that seen in the Borrow Pit. Several adjacent auger columns in this area were terminated by hitting rocks and we suspect that some massive FCR accumulation must be present.

Since the mud drape covers the top of the uppermost cultural layer at Sayles Adobe, when we reach the upper mud drape the cultural layer should be directly beneath it. However,  this cultural layer contains many FCR and often the bucket auger is stopped by the rocks. The auger will dig through most Sayles Adobe sediment quickly, but when you hit a sizable rock … everything stops. This is not considered a bad thing though. Usually when we hit a rock, we bring up chips of said rock that reveal if it is FCR. The FCR fragments tended to smell of sulfur when broken by the auger bit. The FCR encountered  about one meter below the surface tells us that we are hitting the upper cultural layer … jackpot!

So far we have not created schematic stratigraphic profiles for all the auger tests, but we created a preliminary illustration based on a test from the east side of the site. The stratigraphic patterns in this auger test compare well to the stratigraphy observed in the Borrow Pit and Sandbox excavation, so we are anxious to complete augering of the entire site so we can get a better map of the stratigraphy!

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Stratigraphic profile created using data collected from an auger test. This profile matches nicely with the exposed stratigraphy in both the Borrow Pit and Sandbox areas of the site.

Looking back at the GPR research done in January, the upper anomalies seen appear to have been the upper cultural layer. The FCR are in a large enough concentration to show significant feedback from the GPR. Three of our west terrace auger tests were stopped at a depth between 80cm-1m when we hit rock—usually FCR, which the auger could just not dig through.  In fact, the Sandbox excavation area was laid out as the result of our first east-west bucket auger transect.  Next week we should expose the concentrated FCR and see why so many burned rocks are piled up in one area.

Plans for the Future

Auger testing at Sayles is an ongoing process, with more sampling columns on the way. So far, only an east to west transect has been completed. We just started on our north to south transect, targeting more anomalies from the GPR survey. If additional FCR/cultural layers are encountered, it is likely that more units will be opened up for further research. The emerging picture from the bucket auger data is proving to be quite informative and tantalizing.  Hint, hint:  we have encountered deeper layers of mud drape silt and of cultural material yet to be exposed!

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Tori and I very excited about a flake from an auger test!