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!

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Mortar She Wrote

By Amanda Castañeda

Most of the previous ASWT blog posts have focused on our ongoing excavations in Eagle Nest Canyon, with a few thrown in about earth ovens and our undying love for burned rock. So I thought it was time for a little change of pace! This post highlights another very common archaeological feature found in many of the sites within Eagle Nest Canyon and elsewhere across the Lower Pecos Canyonlands —ground stone bedrock features. Bedrock features, as I will often refer to them, include “slicked” areas, shallow grinding basins, deep mortar holes, and everything else in between.

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Amanda cleaning off bedrock features.

I first became interested in bedrock features during my tenure at Shumla Archaeological Research and Education Center. We went to rockshelters across the region to record rock art, and bedrock features were a common occurrence in many sites. Most intriguing were bedrock features that were over 50 cm deep. I thought to myself, what on earth were the Lower Pecos inhabitants doing with these features when you can barely touch the bottom with your fingertips? Further, despite the ubiquitous nature of bedrock features in the Lower Pecos, they represent a largely understudied part of the archaeological record. In part, this is why I chose to explore this prehistoric technology for my recently completed Master’s thesis at Texas State University.

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A volunteer demonstrating the great depth of some of these bedrock features. Neither hand can touch the bottom of these two bedrock mortar features.

Bedrock Features 101

Archaeologists typically categorize these features by morphology and the perceived type of activity (e.g., pounding, reciprocal grinding, circular grinding, etc.). For example, grinding facets are shallow basins likely used to grind foods with a back and forth or circular grinding motion. Mortars are deep holes that were utilized for crushing or pounding, probably using straight up and down motions or possibly rotary or circular motions in some instances. Lastly, “slicked” areas are flat surfaces that have a shiny, smooth appearance and their function is unknown. The highly polished surface could be the result of multiple activities such as polishing hides or another activity that might include oily substances. Ethnographically, bedrock features of all shapes and depths were used for a variety of activities, mostly related to food-processing.

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Three deep “mortars” are surrounded by much shallower “grinding facets.”

While generic terms, such as the ones listed above, have been used in previous bedrock feature research around the world, prior to my study there had not been any bedrock feature research completed in the Lower Pecos.

Therefore, I was most interested in creating a baseline data set of the morphological variation of these features. In other words, are we able to pick out any unique “types” of features and how are these morphologies distributed across the landscape? Further, using other lines of evidence such as use-wear patterns, can we determine what kinds of foods were being processed in these features? Essentially, I wanted to take a broad approach to my research and try to gain a better understanding of how these features were utilized by the hunting and gathering peoples of the Lower Pecos.

Recording Bedrock Features in the Lower Pecos Canyonlands

Data Collection

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Amanda recording bedrock features at Eagle Cave, and undoubtedly suffering from “bedrock butt.”

For my research I recorded morphological attributes (e.g., shape/size), use-wear characteristics (e.g., wear patterns left behind on the rock from different processing activities), and metric data (e.g., measurements) for 824 individual bedrock features at 10 sites using a combination of Structure from Motion (SfM) Photogrammetry (see SfM Revolution) and traditional field documentation methods. I recorded morphological attributes and macroscopic use-wear patterns using the form below.

BRF Attribute Form

I used SfM as the primary mapping and documentation method for each of the bedrock features I recorded. From the 3D data, I was able to create high resolution feature maps, and gather measurements for each feature in the mapping software ArcGIS.

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Examples of feature maps created via SfM and ArcGIS: a) orthophoto of surface; b) a digital elevation model (DEM) of the same surface; and c), a slope model of the same surface derived from the DEM.

Statistical Data Analysis

I focused the majority of my analyses on three different measurements: maximum depth of each feature and two axes across the opening of each feature. To summarize my results, I completed a cluster analysis using the metric data, which resulted in four distinct groups of bedrock features. The majority of the features (97%) fell into one very large, closely related group. I should note that Cluster 1 was comprised of four smaller subgroups, but there is only so much you can do for a M.A. thesis and still finish in decent time (as my committee wisely advised me!). The remainder of the bedrock features formed three smaller groups.

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Looking at the graphic below, it’s easy to see how some of these groups were formed. Cluster 4 features are all extremely deep, between 40 and 60 cm. Cluster 2 features are moderately deep, between 20 and 30 cm. However, there are pieces of the puzzle the graphic doesn’t show. For example, the majority of Cluster 4 features have completely straight/vertical walls, while Cluster 2 features have sloping walls that form an overall conical shape. These types of observations were exciting because they are diagnostic attributes of these clusters that are independent of the cluster analysis. Said differently, they support the distinction of two different cluster which also had two different activities going on.

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As for Clusters 1 and 3, they seem to blur together in the above chart. The reason for this is that Cluster 3 features are defined by at least one considerably long axis at the opening of the feature. Looking strictly at the length of the axis measurements, Cluster 3 separates itself from the rest of the sample. Cluster 1, in both graphics, is all over the map. This cluster contains a very wide range of variation in all aspects of the feature, depth, length, and width.

Axis v Axis

So essentially what the cluster analysis had shown me is that there are distinct morphological groupings of features, and each had a diagnostic characteristic that defined the group (except Cluster 1). The next thing I wanted to determine was if there were any other attributes of these clusters that further support distinguishing them from one another?

Bedrock Features on the Lower Pecos Landscape

First I looked at location. How are these clusters distributed across the landscape? Unsurprisingly, all ten sites have features that are included in the Cluster 1 group. In fact, four of ten sites have features that only fall into Cluster 1. The other three clusters are more restricted in their distributions. Cluster 2 occurs at three sites, Cluster 3 is present at five sites, and Cluster 4 only occurs at two sites. These data suggest that across the region, the majority of the food-processing that occurred could be completed in a non-specialized, Cluster 1-type feature. This could be due to the relatively small amounts of food being processed in most features or to the predominance of certain foods that did not need a specialized surface.

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Use-wear Patterns of Bedrock Feature Clusters

The next characteristic I wanted to examine were the use-wear patterns. Did each cluster have distinctive or diagnostic wear patterns that might help me interpret the types of food that were processed in those features? Before I start throwing terms at you, let me first explain a little bit about use-wear studies on ground stone surfaces. In regards to ground stone bedrock features, differential use-wear across the surface of a feature can show what type of activity happened most recently. Is the surface pecked and rugged, or is it completely smooth to the touch? These conditions tell different stories about what happened last with that particular feature. When making use-wear observations, the objective is to observe traits about the macrotopography, or the high and low points.

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Illustrations of ground stone use-wear patterns. Redrawn from Dubreuil (2004:Figure 1).

Now going back to my data, the use-wear patterns further distinguished the Clusters from one another. Clusters 1 and 3 had very similar use-wear- they had rugged or pecked surfaces with either leveled or rounded high points. Cluster 1 feature walls was a rugged surface with either levelled high points or rounded high points. This suggests the area was first pecked to roughen the surface, and then different activities occurred to produce the modification on the high points of the feature. Levelled high points could have resulted from significant amounts of stone on stone contact (e.g., during fiber extraction), or if the processed material was hard in nature (e.g., seeds). In the instances with rounded high points, the surfaces were initially pecked, and then some sort of “soft” material was processed that smoothed the highs and lows of the peck marks. As the substance moved across the surface and around the high points, the surfaces became rounded. Softer materials potentially include a variety of plants (e.g., baked agave or sotol, nut meats, fruits) and animal tissue.

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Amanda contemplating use-wear.

Cluster 2 features, the somewhat deep ones, had mostly leveled surfaces on the walls with some gradual, smooth rounded high points. This suggests that materials being processed in these relatively deep features were somewhat abrasive nature, and that the individuals using these features did not feel the need to re-peck the sides of the shaft to roughen the surface. The intensive levelling of the walls also supports the probability of a rotary motion being used, as to increase the contact between walls and the material being processed.

The most common use-wear pattern on the walls of Cluster 4 features are rugged upper walls and mostly leveled lower walls. This pattern suggests the upper walls did not come into contact with either the processing implement or the material being processed. Similar to the walls in Cluster 2 features, the lower half of these features must have been relatively full of semi-abrasive materials. This also suggests a pounding motion was utilized rather than a rotary or gyratory motion since the upper walls showed little signs of wear. However, two of the features in Cluster 4 are leveled on all portions of the walls throughout the shaft, suggesting a rotary motion may have caused the leveling.

Now for the Hole Story

So to sum it all up, there are definitely different morphological types of bedrock features in the Lower Pecos. One of my original goals was to put forth a regional typology of bedrock features. Although the cluster analysis resulted in four highly different morphological groups, Cluster 1 includes an incredibly large range of feature sizes and makes up the majority of the data set. Until Cluster 1 is examined more thoroughly for intra-cluster pattering, I think it is premature to create a formal typology. Clusters 1 and 3 are both highly variable and elude a classification that can encompass all of the morphological and metric variation. Other groups (Cluster 2 and 4) are less variable and likely represent a true morphological and functional type. At this time, I will tentatively classify features in Cluster 1 and 3 as general grinding surfaces, features in Cluster 2 as conical mortars, and features in Cluster 4 as cylindrical mortars.

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Examples of bedrock features within each cluster: a) Cluster 1 features; b) Cluster 2 features circled in red; c) a Cluster 3 feature; and 4), Cluster 4 features circled in red.

Behaviorally, the overwhelming presence of generalized features such as the ones in Clusters 1 and 3 makes sense for a mobile, foraging group. These features take very little time to create, and they were likely used to process many different foods, whatever the group could find on any given day. Other feature types (e.g., Cluster 2, conical mortars; and Cluster 4, cylindrical mortars) were highly specialized and only occurred at certain sites. This pattern could have implications about general lifeways for Lower Pecos hunter-gatherers. Perhaps these foraging peoples were using the many sites with general purpose features for a majority of the year, but sites with specialty features could signal use during certain times, such as a harvest or large social gathering. These theoretical ideas along with experimental work can help archaeologists push our interpretations of ground stone bedrock feature technology past just food processing and into theories regarding site reuse and optimal technological adaptations.

Before I began my research, I expected the results to show many more distinguishable groups or morphological types. Undoubtedly, further analysis of the data will yield a greater insight into what morphological groups may be hiding in Cluster 1, which might change how I’ve interpreted the data thus far! There is so much more to learn, these types or groups are not set in stone…well they are, but you know what I mean. There are also other avenues to explore such as residue studies, which could give us an even better understanding of exactly what was processed in a feature. There are experiments to be done to figure out how long it takes to create a feature 50 cm deep in limestone! We’ve only just begun to peck the surface. But isn’t that the most exciting thing about archaeology? The more we learn, the more questions we have, and the whole process begins again.

This blog post is meant to be a simplified summary, there is much more to this story! If you want to learn more about bedrock features in the Lower Pecos, you can download my full thesis from the Texas State Library webpage here.

 

References Cited

Dubreuil, Laure                                                                                                                                              2004    Long-term Trends in Natufian Subsistence: a Use-Wear Analysis of Ground                       Stone Tools. Journal of Archaeological Science 31:1613-1629.

The Developing Tales of Sayles Adobe

By Victoria Pagano

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E.B. Sayles 1932 sketch map of Eagle Nest Canyon.  Note the area labeled “Sandy Adobe.” Courtesy Texas Archeological Research Laboratory, UT Austin.

Tori here, former 2015 ASWT intern and current Texas State anthropology graduate student. This season I am back leading excavations at the Sayles Adobe site as I collect data for my master’s thesis.

The terrace site of Sayles Adobe (41VV2239) sits just within the mouth of Eagle Nest Canyon (ENC), a short distance up the canyon from its confluence  with the Rio Grande. On E.B. Sayles’ 1932 sketch map of the canyon the site area is indicated as “sandy adobe,” with no mention of cultural material. Apparently, it was considered to be just a natural terrace formation.

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1958 photographs showing the site area looking toward the mouth of the canyon (above);  Skiles Shelter as viewed while standing on Sayles’ “sandy adobe” (below). Courtesy Texas Archeological Research Laboratory, UT-Austin.

 

 

During the Ancient Southwest Texas Project’s 2014 field season, the massive June 21st flood (see The Canyon Runs Deep) deposited a thick layer of flotsam atop the back dirt pile for the Skiles Shelter excavations. In order to finish filling in the open excavation units, the crew decided to take fill  from the alluvial terrace deposit nearby. This seemed like a good choice until the crew encountered fire-cracked rocks (FCR) about a meter below a thick bed of sandy Rio Grande alluvium. Digging stopped immediately and the area remained untouched (by archaeologists) until late 2015.

 

 

And so it begins..

In December 2015, a crew of five: Drs. Steve Black and Charles Frederick, Charles Koenig, Amanda Castaneda, and myself, carried out a three-day reconnaissance of the alluvial terrace and 2014 borrow pit with the idea that this as-yet-unrecorded site might make a good thesis research project.

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Discovery borrow pit, pre-clearing and post-clearing, December, 2015.

My initial observations were limited.  It was clear that the locality was an alluvial terrace and that the burned rocks that the 2014 crew had encountered were not likely just discard washing down from Skiles Shelter. But vegetation across the terrace made any sort of determination on the full extent of the site difficult. We cleared just enough vegetation to get a better idea about the morphology of the terrace. The most promising formation model is that large limestone boulders in the canyon bottom and the canyon wall created a catchment for alluvial sediment during back flooding from the Rio Grande. Repeat flood deposits created an open terrace just a few meters downstream from

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Current views of Sayles Adobe from the canyon rim looking toward the mouth of the canyon (above) and (below) the large boulders in the canyon bottom that seem to have formed a massive sediment trap. Skiles Shelter that could be used for certain activities between deposition events. This formation process would make Sayles Adobe a bit different in comparison to other investigated terraces in the Lower Pecos.

During this visit we worked to clear vegetation from and around the initial exposure to facilitate testing at the site. A quick surface reconnaissance (mostly on hands and knees) revealed scattered FCR on the surface at multiple locations across the terrace. Frederick and I cleaned and squared off two exposed faces of the borrow pit to examine the stratigraphy. I soon discovered a thin, compact layer of very fine silt, directly above (covering) several burned rocks amid carbon-stained matrix. Frederick recognized the silt layer as a flood (mud) drape.  The stratigraphic sequence looked very promising.

 

 

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Extent of the flood drape exposure at the end of the December 2015 visit. You can clearly see the color and textural changes.  From top to bottom: light brown sandy loam, tan silt flood drape, and burned rock and carbon-stained matrix below.

 

Understanding the Geoarcheaology of the Canyon

The excavation and analysis of Sayles Adobe is being conducted as part of my Master’s thesis research in order to reconstruct and understand the natural formation of the terrace and document the prehistoric uses of the locale. I hope to be able to address four main research questions:

  • What is the nature and timing of flood events during the human history at Sayles Adobe?
  • What can the Sayles Adobe terrace deposits tell us about the climatic and environmental conditions at the time the formed?
  • Do flood deposits at Sayles Adobe correlate to other flood deposits seen in shelters in the canyon?
  • How do site use behaviors seen at Sayles Adobe relate to other sites in the canyon?

The primary focus of our excavations will be to collect data aimed towards the cultural and natural formation processes witnessed at the Sayles Adobe terrace. This will form the foundation for my interpretation and analysis of behavioral patterns witnessed at the site.  The cultural materials and geoarchaeological samples will be analyzed and compared to the other sites within Eagle Nest Canyon.

2016 Sayles Adobe Investigations

Our first session focused on testing the Borrow Pit area that was exposed in 2014 and cleaned up in December 2015. During this time myself, Spencer Lodge, and Kelton Meyer, worked to carefully peel away the mud drape in the north to south profile (PS01) and reveal as much stratigraphy as we could.

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The mud drape could easily be “peeled” off in chunks from the charcoal stained sediment below.

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Annotated Profile Section 01 (PS01).

 

 

 

 

 

 

 

 

 

To add greater resolution to the Sayles Adobe tale, Tiffany Osburn of the Texas Historical Commission visited Sayles and carried out a ground penetrating radar (GPR) survey across the terrace. Using two different range antennas, she made multiple passes in a grid and in transects to provide us with an idea of what might be under the surface that we wouldn’t know without completely excavating the site. The GPR results  will aid in the interpretation of (and guide) further excavations at the site.

A priority of our second session at the site was to continue work in the Borrow Pit area. The ultimate goal of the work here is to create a deep profile that can be used to document and sample the natural and cultural stratigraphy of the site.

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Partially annotated results of the 270Hz GPR survey. Courtesy of Tiffany Osburn.

Using GPR data, we began working to ground-truth these results by conducting bucket auger tests that reach up to 3m deep along the East-West and North-South axis of the site.  (More on our auger testing in a few weeks, when intern Justin Ayers takes on the Sayles auger survey).

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Ongoing investigations at Sayles Adobe.

Some readers might ask, why even bother with a site like Sayles Adobe in a canyon that has such culturally rich rockshelters?  In comparison to those sites, Sayles may seem like a pipsqueak with not much to offer.  But, in truth Sayles is no less exciting or enriching than the sheltered sites. Sayles provides an opportunity to see what other activities were taking place in Eagle Nest Canyon that we can’t see in the shelters or along the canyon rim.  Our initial work shows that we have at least one sealed cultural layer that has not been disturbed by later occupation. In contrast, hunter-gatherers returned to the rockshelters time and time again, with the remains of each visit co-mingled with that of the last and mixed through pit digging, plant baking, and many other activities. As ASWT has documented in high resolution, the rockshelters have palimpsest deposits with complicated stratigraphy and few, if any, expansive areas of sealed cultural deposits.  Sayles Adobe has the potential to add a new level of understanding to human behaviors and natural formation processes of deposits in the canyon.

Our goal isn’t just to put together a chronology of the use of the canyon over the past few thousand years, it is to weave together an understanding of the people and the natural world in which they lived.  Stay tuned for further developments.

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A Sabinal arrow point has just come to light about 10 cm below the flood drape.