Wednesday, December 5, 2012

Imported Ceramics, or the Lack Thereof

We’re still waiting for our Neutron Activation Analysis ceramic results from Missouri University, but in the meantime a look at decorative types can give some hint as to the patterns we may get.  The most striking of these (so far, at least) have to do with imports. Patterns of imported ceramics can tell us who the occupants of Calixtlahuaca were interacting with, and whether these patterns of interaction changed over time. This analysis is still a work in progress, so please consider all numbers given here as provisional estimates.

The first pattern is the increase in the imports over time. At Calixtlahuaca, there are very few imports from anywhere during the Middle Postclassic (the period prior to the foundation of the Aztec Empire), followed by a steady increase during the Late Postclassic-A and Late-Postclassic B (The periods when the Aztec Empire existed, divided approximately around the time the Empire conquered Calixtlahuaca). This pattern of steady increase is consistent for both Aztec style ceramics, and the few imports from other regions.
The second pattern is the low diversity of imports.  The ceramics that are imported overwhelmingly come from the Basin of Mexico.  None of the households had even a single piece of Tarascan ceramics, (though we do find West Mexican copper/bronze and obsidian at Calixtlahuaca) and the few other imported pieces come primarily from Morelos. My (currently unquantified) impression is also that even the Aztec imports represent only a subset of the motifs and/or variants of these types that are present in the Basin of Mexico. For example, with the exception of a piece or two, all of the polished redwares (guinda) that we excavated feature one of two patterns. 

Both of these points are in direct contrast to contemporary Late Postclassic sites in Morelos.  There, the LPC-A frequency starts out much higher than at Calixtlahuaca and drops during the LPC-B (Morelos data taken from Earle and Smith, 2012).  Sites in Morelos also show a higher diversity of sources for imports (Evidence – The sheer number of regional types in our classification guide which I’ve never seen an example of, and when I’ve asked Mike about them, he says “Well, we get them in Morelos!”. )

Wednesday, July 4, 2012

At long last...

586,394* sherds
1,289 lots
6 lab seasons
1 dedicated crew

I would like to announce that we’re officially done classifying the ceramics from the 2007 excavations.  I’d like to thank everyone who washed, classified, skimmed, cataloged, entered data, or supplied coffee to make getting here possible.

Now we just have to make sense out the boogers.  This will require more coffee.

Judith and Janeth classifying the very last lot

*Give or take a few dozen.  We still have to enter the last two weeks of classifications into the database and differences between the rough count at washing and the final classification can cause the numbers to bounce around a bit.

Monday, June 18, 2012

Cerro Toloche

 Two weeks ago, Julie and I visited the archaeological project at Cerro Toloche, just north of the center of Toluca. The project has finished a topographic mapping of the hill, surveyed the surface for artifacts, and are currently digging systematic test pits across the whole hill.  Daniel Granados, who is the field director for the project, took our survey methods into consideration when he was developing his own, so hopefully we will be able to compare the two datasets.  They plan start more extensive excavations this fall.

Toluca from the top of Cerro Toloche.  Note the location of the cathedral.

Cerro Toloche was the center of Tollocan, or prehispanic Toluca.  The site is only five or six kilometers from Calixtlahuaca and the relationship between the two prior to the Aztec conquest is unclear.  (For that matter, whether the Tollocan existed prior to the Aztec conquest of the region is open to question.) 

From the archaeological evidence so far, it looks like Cerro Toloche had at least two groups of monumental architecture and a primarily Postclassic occupation.  The artifacts the project has recovered so far look very similar to the ones from Calixtlahuaca, with a mix of Matlatzinca and Aztec sherds, plus a few figurines from earlier time periods. Hopefully the excavations will clear up whether there is a single, mixed Matlazinca/Aztec component or a primarily Matlatzinca component followed by a mixed one.

Wednesday, May 23, 2012

"Historia General Ilustrada del Estado de México"

The book series, Historia General Ilustrada del Estado de México has finally been published! The Presentación de Libro event will take place May 24, 2012, in the Colegio Mexiquense, Sede Casa Toluca, Aquiles Serdan #201, Col Centro, Toluca, at 17:00 hours. Dr. René García Castro will provide the comentary.

This series was assembled to celebrate the centenary of the state in 2010, but publication delays held up the publication.

This article has information about Calixtlahuaca:

Smith, Michael E.
    2012    Las ciudades prehispánicas: su traza y su dinámica social. In Nueva Historia General del Estado de México, tomo 2, periodo postclásico, edited by Rosaura Hernández Rodríguez and Raymundo César Martínez García. El Colegio Mexiquense, Toluca.  (Not sure about the precise citation; it looks like the volume names are different now. I haven't seen the volume yet).

Monday, May 7, 2012

2012 and the End of the World

Nice comic from Bizarro last week. It is incredibly ironic that the Mayas did NOT predict the end of the world (in 2012 or any other time) and they get all the publicity, while the Aztecs DID predict the end of the world and no one pays any attention! Well, maybe in 2027 we will get some mileage out of the Aztec prediction.

See my earlier post on Publishing Archaeology about the bogus 2012 predictions.

And this is another good one, widely reproduced by now:

For the ancient residents of Calixtlahuaca, the end of the world came in the 16th century. Once Tenochtitlan fell to Cortés, it wasn't long before smallpox and other diseases, coupled with forced evacuation to Toluca, brought the city of Calixtlahuaca to a halt.

Friday, March 16, 2012

I thought that was a WHAT? Inter-analyst variability and yet more ceramic seriation

One of those little problems that archaeologists politely ignore most of the time is the issue of inter-analyst or inter-annual classification variability. A couple weeks ago, I was skimming Ian Robertson’s dissertation and realized that many of the issues he describes for the Teotihuacan mapping project ceramic data could well apply to most archaeological projects fifty years after the fact.

For the Calixtlahuaca project, our excavated ceramics have been classified by a whole bunch of different people over the last five years. In an effort at standardization, our lab procedures have always required that a second person check the classification of a bag of sherds before it is finalized, and all previously classified examples of a type are reclassified if we make a major change in the sorting rules. Despite this, I know from personal experience that our sorting rules have drifted a bit over the years. (This also means that our classification manual doesn’t quite match the way things actually work, much to the frustration of anyone new trying to learn the system.)

Because of this cluster of potential issues, I (with lots of help from Judith and Janeth) did a quick classification check/ reclassification of all the lots that I was pulling attribute samples from last year, since the bags were out anyways. We went through probably two thirds of the domestic context sample this way, which should cut down quite a bit on any inter-observer variability within the DCS as a whole. My gut impression was that we made quite a few changes to lots classified during the 2007 and 2008 seasons, with things stabilizing after that. During the first time period we were still apparently working out some of the basic dividing lines (like how to tell the difference between a plain olla body and a plain bowl body) for this particular ceramic assemblage. For lots classified in later seasons, my impression was that the reclassification accounted for some subtle variation due to gradually shifting dividing lines between types, with most changes being from one sub-variant to another within a single decorative family.

As of earlier this week, this semester’s undergraduate volunteers here at ASU finished entering all of the reclassification changes into the ceramic database, which allowed me to do a final ceramic seriation run to see if all the reclassification had effected the dating of particular contexts. (At least, I hope it’s the last run!) The run seems to have produced the usual handful of changes in the phase assignment of particular stratigraphic capas, so if you are analyzing any sort of material from the project by phase, you should probably check in for the updated list in about another week.

Now, while I’m thinking about it, I really ought to go update our ceramic classification manual/type description book, so that it does match how we actually sort sherds…

Thursday, February 23, 2012

NEWS From the Survey: Obsidian XRF

Hi everyone! It's Julie here.

I'm still working with the survey data at Calixtlahuaca, trying to make some sense of how neighborhoods were organized culturally and economically. Specifically, were the material differences in class, consumer preferences, ritual, and procurement distributed in clusters in space. Most of the data I use in my analysis is ceramic and seems to suggest that there was limited social clustering based on class and no social clustering based on consumer preferences. I'm still not done with the analysis yet, so there is more information to wring out of the data. However, the obsidian data tells a different story, one where different neighborhoods obtained obsidian from different sources. In fact, neighborhoods in different regions of the site seem to have similar proportions of obsidian. But I'm getting a head of myself.

The obsidian data I'm looking at are the results of an XRF study of 155 pieces of surface collection obsidian representing 19 of the 20 neighborhood units at the site. These pieces of obsidian were sent to Dr. Michael Glascock and his team at the Missouri University Research Reactor. They took care of the chemical analysis and source attribution of the Calixtlahuaca survey obsidian. I got back a file with the data from the XRF analysis and the sources for each piece of obsidian.

We at Calixtlahuaca have obsidian from six known and one unknown source. The green obsidian is confirmed to come from Pachuca. We also have grey obsidian from Ucareo, Zinapecuaro, Otumba, Malpais, and Zacualtipan. The overall distribution of grey obsidian by source is:

Ucareo 56.4%

Zinapecuaro 0.7%

Otumba 38.6%

Malpais 0.7%

Zacualtipan 1.4%

So most of the grey obsidian from the survey comes from West Mexican sources! We kind of thought that was going to be the case, but its awesome to have it confirmed.

Another interesting thing that came out of this analysis is what kinds of artifacts are being made with this obsidian. Of my sample, we had 86 pieces of obsidian for which we also had information on lithic technology. This was provided by Dr. Bradford Andrews from Pacific Lutheran University. Based on that information, the people of Calixtlahuaca preferred some obsidian for specific uses over others.

Looking at our two most common grey obsidian, Ucareo and Otumba, the preferences were:

Ucareo Otumba

Bipolar Technology 65% 30%

Prismatic Blades 84% 9%

Unifaces and Bifaces 0% 100%

I think that's pretty neat!

So, I'm still looking at the data and making interpretations. This is by no means a final report, but a work in progress. But Angela kept poking me to post this information. Hope you are as excited as I am.

Monday, January 16, 2012

We exported a bunch of artifacts

Just before Christmas I received two boxes of artifacts, sent FedEx from Mexico. We exported a bunch of potsherds, obsidian tools, and charcoal for various technical analyses. Angela was working in the lab all fall, so she had the honor of lugging these boxes to Mexico City and hassling out the final steps of paperwork. To get artifacts out of Mexico, we have to document them thoroughly (with catalogs, descriptions, drawings, photos, etc.) and then convince the Mexican archaeology authorities that we are doing rigorous analyses and have a valid reason for exporting artifacts. Once they approve, officials have to seal up the boxes, and obtain the export forms for Mexican and U.S. Customs. Then someone (Angela in this case!) has to get the material either to the U.S. directly (by car or plane), or to a FedEx office for shipping.

So, now we will submit 20 or 30 charcoal samples for accelerator radiocarbon dating at the University of Arizona; we will send sherds off to Jenny Meanwell for thin sectioning and petrographic analysis (see Angela's post on selecting this sample), and Adrian Burke will get a shipment of obsidian for sourcing using X-Ray flourescence.

We sampled a couple of nearby obsidian sources that are not well documented in the literature in 2010. I thought we had a blog post on this sampling, but it looks like in all the haste and activity at the end of the lab season, no one got around to writing this up. I guess we were so overwhelmed at visiting the Otomi Ceremonial Center that everyone forgot that we only saw that place because we were in the area looking for obsidian. We found a hill completely covered with obsidian. It was wild, which is why I am having such fun in the nice photo that Brad took of me that day. Unfortunately, Brad and Adrian don't think that we have much obsidian from this source, which is pretty low quality material. But we did get source samples and the chemistry will tell......