Thursday, October 3, 2013

Subsets and Samples

By Mike Smith, with comments from the peanut gallery by Angela Huster
After a rather involved set of phone conversations and emails among various project members trying to establish the frequency of green obsidian at the site during each phase, we realized that half our problem was the we were working with different samples. We had defined the Domestic Context Sample of lots strongly associated with dated houses several years ago, but any analyses that wanted to work with a larger sample were a free-for-all. 

Based on Mike's previous projects in Morelos, we defined five samples based on their value for the analysis of domestic artifacts and conditions. These run from the Domestic Context Sample, (now called Domestic Sample 1, or DS-1), which consists only of well-dated midden deposits, to DS-5, which is the entire sample of all excavated contexts at the site. In addition there are other samples of lots that make sense for particular analyses or materials. Most of these samples are nested; e.g., all other samples include DS-1, and DS-5 includes all other samples. Samples DS-3 and DS-4 intersect in a non-nesting fashion, however.

DS-1 (the Domestic Context Sample).   178 lots.
             This sample consists of well-dated midden deposits associated with houses. It can be subdivided into domestic components; that is, deposits from a single phase in a single unit. It was designed to provide a robust sample of materials from contexts with abundant artifacts for optimal quantification. This sample is used for:
      Household comparisons of ceramic type frequencies.
·         Ceramic type frequencies for the Aguas Celestiales chapter

It is also the source of sub-samples for particular technical analyses, including:
Ceramic attribute recording

·         Obsidian source samples
·         Ceramic petrographic samples
·         Angela’s NAA samples

DS-2 (the Extended Domestic Context Sample).  340 lots.
            This sample extends the domestic context sample to include other lots dating to the same phases at individual units. Units without representation in the domestic context sample are not included in DS-2. The advantage of a larger sample is offset by the inclusion of contexts such as fill and colluvial overburden whose association with the occupation of a house is less secure. This is used for:
·         Interhousehold comparisons of rarer items in Angela’s dissertation analyses – ground stone, copper, jewelry, whorls, and molds

DS-3 (the all-Phased sample)  1,146 lots.
            This sample consists of all lots phased to a particular period. It includes the transitional or uncertain phases (3, 5, and 44*) and phase 1 (pre-Postclassic). This is a much larger sample than DS-1 or DS-2, and its value lies in the fact that it includes the maximal number of lots that can be phased. Many of the lots have not had their ceramics classified; they are phased through stratigraphic position or associations with lots dated from their classified ceramics and/or radiocarbon dates. Its disdvantage is the inclusion of many lots whose direct association with the house occupation of each unit is more tenuous (fill, overburden, etc.). Its primary use is for comparing frequencies of rare artifacts. It is used for:
·         Rare artifact types by phase for the general project

DS-4 (the Classified Sample)  664 lots.
            This is the sample of lots whose ceramics have been classified. It has two related disadvantages compared to sample DS-2: many of the lots have not been phased; and many of the lots have only a few sherds. It is not used in any analyses.

DS-5  (all Excavated Lots).  1,668 lots.
            This is the total number of lots that were excavated. It includes many tiny lots from Alex’s soil sampling, lots from architectural excavations, and other small lots whose value for artifact analysis is minimal. It’s primary use is to generate inventories of all excavated artifacts of a given type, irrespective of phasing or quality of context. This is useful for descriptive purposes (i.e., we want to describe all of the figurines, not just the ones that fall into a more restricted sample), but not for making comparisons among units or parts of the site.

The following diagram shows the relationship among these samples.
 If anyone needs to know which samples their data fall into, please contact Angela.

Tuesday, July 2, 2013

Working on ceramics in Toluca

Mr. Monkey-Helmet
I'm in Toluca for a few weeks working in our lab at the Colegio Mexiquense. I am wrapping up a variety of final tasks with our ceramics. One thing I am doing is organizing the miscellaneous ceramic forms, checking catalogs, recording attributes, drawing the artifacts, and taking photos. Here are a few photos to show what I've been doing.

The first photo is a monkey face, someone I call Mr. Monkey-Helmet. This is classified as a ceramic appliqué, which means it was stuck on the side of some object. In the profile view you can see the projection where this attached to the wall of the vessel. The problem is, what kind of vessels had monkey faces sticking out their sides? I really don't know (let me know if you have a

 Next we have some tobacco pipes. These little pipes were most abundant in western Mexico, among the Tarascans and other cultures. We found more pipes than I did in my earlier excavations near Cuernavaca, but they are still pretty rare items. Not all the houses had pipes, but since they are rare it is tough to tell whether this is significant or not.

Here are a few stamps. Ceramic stamps, like the one on the top left, are common at Aztec sites in the Valley of Mexico and in Morelos. These were regular household items at Yautepec and the other sites I excavated near Cuernavaca. But they are quite rare at Calixtlahuaca. In fact, the two on the left are the only Aztec-style stamps we excavated. The rarity of stamps at  Calixtlahuaca is one of many indications that the site was not closely integrated with the styles, culture, and practices of the Aztec heartland in the Valley of Mexico. My Morelos sites, on the other hand, matched the materials and styles of the Aztec center much more closely. The object on the right is unusual. The design does not match Aztec stamps, and it lacks a tab on the back. If you have any suggestions about what this may be, please let me know. Maybe it is from an earlier time period.

Tlaloc vessels
When he excavated at Calixtlahuaca in the 1930s, José  García Payón found a bunch of offerings of Tlaloc Vessels (tall, crude, ugly vessels with Tlaloc faces) in Temple 4, which then became known as the Tlaloc Temple. We found a few fragments of probable Tlaloc vessels in our excavations, but not very many. If you have seen the Tlaloc vessels from offerings at the Templo Mayor in Mexico City, these crummy sherds look pretty pathetic. Ah, the curse of household archaeology. We excavate fragments of everyday items, and rarely fine a beautiful complete object worthy of a museum. Oh, well.

Imports from Morelos

And finally, a photo of sherds from vessels imported from the state of Morelos. Contemporary sites in Morelos have move imports from the Toluca Valley than the reverse. Aztec-period houses in Morelos have a much higher number of imports overall, and imports from a larger number of places, than the houses at Calixtlahuaca. One interesting thing is that these Morelos imports span the entire sequence. At the top right is Morelos-Puebla Black-on-Orange, an Early Aztec type, and the two bottom decorated sherds, Morelos Type I, are from the final half of the Late Aztec period in western Morelos.

Brad Andrews is down here too for a few days, checking the obsidian. Next week I return from the 70 degree weather of Toluca to the 115 degree heat of Phoenix.

Wednesday, April 24, 2013

The Life and Times of Burial 4

This is the second post by this semester's student volunteers on bioarchaeological research at Calixtlahuaca.

This post includes photographs of human bone.

By Kea Warren

                Bioarchaeologists work with the traditional archaeologists to try to understand the way a group of people lived based on the remains they leave behind.  While working on the site of Calixtlahuaca in Mexico, Doctor Michael Smith and his team uncovered four full burials and the areas with broken bone rasps discussed in the previous post, all of which were later analyzed by Kristin Nado. Six burials is a relatively small sample size. While the site provides insight to the lives of a small group of people, archaeologists tend to prefer larger samples to understand trends and diversity among the population. From this smaller sample, bioarchaeologists can observe individuals and how those individuals lived, as will be discussed later, though the broader understanding of the group is limited.  
Map of Burial Locations
Three burials are physically close together, which may imply some sort of familial relationship between burials 5, 4, and 3 (which contain two adult males and an adult whose sex is unknown).  The two of these three bodies with preserved feet share a congenital condition known as non-osseous tarsal coalitions. This condition is also found in burial 2, which is from a different house excavation.  According to Nado, tarsal coalitions are when two or more tarsal bones are connected by bone or cartilage. This union of bone can be painful, and can also affect the sufferer’s ability to walk.  Further study of the inhabitants of Calixtlahuaca would provide a better understanding this condition in the region. If other remains were uncovered, it would allow bioarchaeologists like Nado to analyze if the condition is regional or possibly only specific to certain groups. DNA evidence of the relationship would strengthen the claim.
Beyond this potential familial relationship, the man in Burial Four has pathologies that are not found in the other burials.
Burial 4
                Burial Four is a male, who was between 25 and 29 years old at the time of death. Based on the man’s bones, Nado could immediately identify several pathological problems that give insight into the life of this man.  The tarsal coalitions are present, which would probably have caused pain. The lip of his acetabulum (colloquially known as the hip joint) appears to have extra articular surfaces. Nado has hypothesized that this may be due to a dislocation of the hip earlier in his life that was never realigned.  This would have been extremely painful, if not completely crippling to individual in Burial Four. The injury was sustained long enough before death that the bone had time to repair itself and try to accommodate the new location of Burial Four’s femur. This would have taken years.
Cyst in Burial 4's femur
His left tibia is also of interest.  It is unlike any other long bone found on site. Inside normal long bones is the medullary cavity, where the marrow is found. In Burial Four’s tibia, there seems to be a bubble of bone. The bioarchaeologists of SHESC remain puzzled as to what it could be, though it has been suggested that a cyst in the bone ossified, and that this is what remains.
                More can be learned from his skeletal remains. The teeth on the left side of his mouth are significantly more worn than those on the right, which Nado has suggested may have been due to use of his teeth for things beyond chewing. Was this for some task he performed because he could not walk?  Only Burial Five had a similar, albeit less prominent, wear pattern, also known as “bilateral asymmetry”. If more mandibles/maxilla can found at the site, more research into the presence of this wear could be performed. Was it specific to a group or family? What caused it? What does this tell us about social organization at the site and the relationship between Burial Four and others of his time? 
                While not everything that happened in life can be viewed in the skeletal remains of a person, bioarchaeology offers a glimpse into the lives of those long gone.  Thanks to Dr. Michael Smith, Angela Huster, Juliana Novic, Kristin Nado and the Calixtlahuaca team for their efforts to discover more about how people lived long ago.