Taken with a Grain of Salt: Experimentation and the Chemistry of Archaeological Ceramics from Xaltocan,Mexico

Neutron activation analysis (NAA) of ceramics from Xaltocan (n?=?651) displays high values for sodium and potassium and low concentrations of many transition metals and rare earth elements compared to other sites in the Basin of Mexico. Given that Xaltocan was situated on an island in the middle of a saline lake, the potential reasons for this chemical signature are diverse. On one hand, if the sodium and potassium were elevated due to some behavioral aspect of the potters, the Xaltocan chemical groups provide a glimpse at the behaviors of Xaltocan potters that permit more precise source designations. On the other hand, if this chemical fingerprint arose due to contamination in a saline post-depositional environment, the Xaltocan chemical groups would not be valid references for provenance studies. To evaluate these alternative hypotheses, we employ several lines of evidence: (1) comparison of the Xaltocan ceramics to over 5,000 NAA assays of clays and ceramics from the Basin of Mexico, (2) experimental doping of clays with water of different salinities and fired to different temperatures, (3) leaching experiments of archaeological pottery sherds (n?=?22) recovered from the site of Xaltocan, and (4) laser ablation–inductively coupled plasma–mass spectrometry of the clay and temper fraction of a small sample of Xaltocan ceramics to determine which component is responsible for the elevated sodium and potassium values. The results suggest that the high sodium and potassium values were present in the ceramic paste before firing. We then use these newly established reference groups to better understand the role of Xaltocan in the regional economy. The type of experimentation employed in this study has proven to be an important method for determining the behaviors of ancient potters and distinguishing them from post-depositional processes.     

Prosperity,power, and change: Modeling maize at Postclassic Xaltocan,Mexico

Documenting the relationship between agriculture and political economy occupies the center of much research and debate in anthropological archaeology. This study examines this issue by focusing on maize at Xaltocan, a Postclassic community located in the northern Basin of Mexico. We consider how different mechanisms of distribution, circulation, and production can influence maize variation. We analyze maize variability through time at Xaltocan and the community’s chinampa system and interpret patterns of variation in relation to its historical trajectory. This methodological and interpretive approach offers an innovative means to understand how agricultural practices transformed in relation to changing conditions of prosperity and power, especially the links between tribute, market exchange, conflict, and regional demography. Our study also speaks to broader, dichotomous perspectives that model the organization of agricultural systems, revealing that the strategies of both agriculturalists and the state often converge at local levels.     

Testing the accuracy of portable X-ray fluorescence to study Aztec and Colonial obsidian supply at Xaltocan,Mexico

This article demonstrates the accuracy of non-destructive portable X-ray fluorescence (pXRF) for the study of obsidian in central Mexico. Obsidian sources were identified for a sample of 103 artifacts from the site of Xaltocan, which spanned the rise and fall of the Aztec empire and the first centuries of Spanish colonial rule (AD 900–1700). Sources were assigned by comparing pXRF measurements with previously published source data and were verified using the standard techniques of laboratory XRF (lXRF) and instrumental neutron activation analysis (INAA). Additional tests of potentially confounding factors show that neither length of read time, presence of surface residue, nor incomplete detector coverage due to small artifact size compromised our ability to attribute sources to artifacts. Concave surfaces did decrease the accuracy of readings because of the greater distance between the artifact and the detector. Our results provide new insight into the stability of supply networks and markets well into the Colonial period as well as the homogenizing tendencies of the Aztec market system.     

Domestic economies and regional transition: Household multicrafting and lake exploitation in pre-Aztec Central Mexico

This article takes a micro-archaeology approach to investigating household production strategies using data derived from Early to Middle Postclassic (A.D. 900–1350) houses from Xaltocan, Mexico, an island capital in the northern Basin of Mexico. I examine household production strategies by integrating multiple lines of evidence including microartifacts, soil chemistry, and macroartifact remains to document a diversity of household production activities, including the manufacture of goods that are typically invisible archaeologically such as foods and perishable goods. Next, I consider changes in subsistence practices through time in order to understand household scheduling and labor allocation strategies. The results indicate that households in pre-Aztec Xaltocan not only pursued diverse economic strategies, but also engaged in multiple types of production activities, including the manufacture of food products and other utilitarian goods derived from lake resources. I conclude that households were fundamental to economic development in ancient political economies and were enmeshed in broader systems of power and networks of exchange.     

TRANSPORT AND SUBSISTENCE PATTERNS AT THE TRANSITION TO PASTORALISM,KOOBI FORA,KENYA

The Turkana Basin in Kenya has an extensive record of Holocene activities relating to mobility and economy of foraging and herding communities. Obsidian is only known from a few key localities in northern Kenya. As such, the use of obsidian as a toolstone material, commonly used during the mid‐Holocene, provides one way to trace exchange, interaction and population movements during the transition to pastoralism. We employ X‐ray fluorescence to characterize obsidian artefacts from four Pastoral Neolithic assemblages. Data reveal a highly mobile and diversified population that used watercraft to access and transport obsidian resources. Specifically, the use of the North Island obsidian source in Lake Turkana indicates that boat use was significant during this transitional period. The incorporation of watercraft transport and aquatic resources in our analyses of Pastoral Neolithic sites affords a greater understanding of subsistence, mobility and economy in this important period in East African prehistory.     

Mapping ancient chinampa landscapes in the Basin of Mexico: a remote sensing and GIS approach

This paper uses remote sensing data to document a raised field, chinampa system adjacent to the Postclassic kingdom of Xaltocan in the northern Basin of Mexico. Various forms of landscape information; historic records and maps as well as remote sensing; are considered to understand the chinampa system. The remote sensing data examined include 1950s aerial photographs, Landsat 7 data, and Quickbird VHR, multi-spectral imagery. This article evaluates the utility of each of these forms of data to identify buried chinampa features and integrates them in a GIS to produce a map of Xaltocan's chinampa landscape. Canals of various sizes and hydrological positions comprised the chinampas and integrated the system together. Occupying at least 1500–2000 ha, Xaltocan's chinampa system represents the largest pre-Aztec, chinampa system in the Basin of Mexico.     

A provenance study of archaeological obsidian from the Andahuaylas region of southern Peru

To date, most obsidian sourcing studies in the Andes have concentrated on the highlands and Titicaca Basin of far southern Peru and northern Bolivia. Toward achieving a more complete understanding of the region, this paper offers new data on the long-term prehistoric obsidian procurement and consumption patterns in the Andahuaylas region of the south-central Peruvian highlands. Obsidian sourcing data from Andahuaylas are particularly interesting since the area is centrally located among several important regional obsidian sources. A total of 94 obsidian samples from a range of sites of different temporal periods were chemically analyzed using portable X-ray fluorescence (PXRF), as well as laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results demonstrate a number of interesting trends, the first of which is the long-term importance of the Potreropampa obsidian source to populations of the Andahuaylas region from at least the early Formative period (∼2500 BCE). Secondly, the results indicate that procurement strategies by local populations in Andahuaylas were primarily reliant on nearby (<150 km) obsidian sources. Finally, the paucity of more distant, yet widely exchanged, high quality obsidian (i.e., Chivay, Alca) confirm that as a region, Andahuaylas was more heavily connected economically (and likely culturally) with local areas to the south (Apurímac) and to the west (Ayacucho).     

Coastal Maya Obsidian Tool Use and Socio-Economy in the Late Postclassic-Early Spanish Colonial Period at San Pedro,Ambergris Caye,Belize

Microscopic use-wear analysis of the obsidian artifacts recovered from Late Postclassic-Early Spanish Colonial occupations at the site of San Pedro yields useful information for interpreting Maya socio-economic activities. Obsidian traded into the community was used for a variety of tasks with emphasis placed on subsistence and domestic manufacture associated with marine resources, including intermittent and contingent crafting. Trade in obsidian and marine resources likely provided San Pedro community members access to inland economic networks and enabled the acquisition of resources not found on the caye. Microwear on chert and obsidian tools indicates relative stability in the traditional lives of the San Pedro Maya in the 15th–17th centuries a.d. Although the San Pedranos likely suffered to some degree from coastal raiding and the introduction of epidemic diseases by the Spaniards, their off-shore location provided them some protection from the upheaval experienced by the Maya in mainland communities.     

Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence.     

Early Olmec obsidian trade and economic organization at San Lorenzo

The Olmec were the first complex society to develop in Mesoamerica between 1800 and 600 cal B.C. The earliest large Olmec center during this period was the archaeological site of San Lorenzo which emerged as Mesoamerica's first large ritual and political center between 1400 and 1000 cal B.C. San Lorenzo's growth as a prominent center included the development of long distance trade relationships with adjacent areas of Guatemala and highland Mexico. High precision chemical analysis of obsidian imported for use in the fabrication of cutting tools is used to reconstruct the growth, size and extent of San Lorenzo's interregional exchange networks with areas of Mexico and Guatemala where obsidian occurs as raw material. A total of 852 obsidian artifacts were analyzed to reconstruct changes in obsidian procurement between 1800 and 800 cal B.C. This represents one of the largest samples of sourced obsidian from a Mesoamerican site and it provides a comprehensive picture for the development of interregional trade networks for Mesoamerica's first large Olmec center.     

Metallurgical ceramics from Mayapán,Yucatán,Mexico

Recent excavations at the Postclassic (AD 1050–1440) Maya site of Mayapán, Mexico, have uncovered a variety of metal objects, metal production debris, and ceramic objects that appear to be linked to metallurgical activities at the site. Our present study investigates a corpus of small ceramic objects to determine if these objects was used in metallurgical processes such as lost-wax casting. A variety of analytical techniques was utilized, including x-ray fluorescence, electron probe, petrography, and reflected light microscopy. Metal residues were detected on the surfaces of several objects, and copper prills were identified within the ceramic fabric, suggesting that the ceramics were exposed to liquid metal during remelting and/or casting events. A comparison of the microstructures of these metallurgical ceramics to typical ceramics from Mayapán demonstrates that the fabrics are very different, and suggests that the metallurgical ceramics were specifically engineered to function in the high temperature environment required for metallurgy. The distribution of metal and metallurgical ceramics across the site of Mayapán suggests that metal production activities may have been more widely distributed and practiced than earlier thought.     

Macusani obsidian from southern Peru: A characterization of its elemental composition with a demonstration of its ancient use

Transparent obsidian artifacts have been reported for the northern Lake Titicaca Basin. Based on instrumental neutron activation analysis (INAA) of these artifacts a distinct chemical group was identified. Yet, the location of the source of transparent obsidian in the southern Andes remained unreported in the archaeological literature. This paper reports on the chemical composition and geographic location of a source of transparent obsidian from the Macusani region of Peru. Through the use of INAA and portable X-ray fluorescence (PXRF) we demonstrate that Macusani obsidian or macusanite comprises (at least) two chemical groups. One of these groups was used for making artifacts during the Archaic Period. Artifacts made of this obsidian were found more than 120 km from the source and yet, one-third of the obsidian artifacts encountered at Macusani were from the non-local source of Chivay which is 215 km to the southwest.     

Book Reviews

Abstract

Obsidian studies play an integral part in archaeology around the world, particularly in the Americas, but few archaeologists have employed obsidian studies to understand Native American life at historical archaeological sites. Yet, obsidian sourcing and hydration analysis can provide critical insights into site chronology and use, lithic recycling, and procurement and trade at contact and colonial sites. Obsidian geochemical sourcing and hydration analyses of a 19th-century rancho site in northern California have revealed new information on Native Americans who labored there in the second quarter of the 19th century. The obsidian data indicate a significant amount of lithic manufacture and use, a change in obsidian procurement in the 1800s, and an unprecedented number of obsidian sources represented on-site. The implications for general obsidian studies, as well as for regional archaeological issues, concern the problems with popular sourcing methods in northern California and the need to revisit current understandings of the first micron of hydration rim development.     

1500 Years of Pottery: Neutron Activation Analysis of Northern Chilean Domestic Ceramics from Caleta Vitor and Clay Samples from Nearby Valley,Coast and Highland Contexts

This paper presents the findings arising from neutron activation analysis (NAA) of northern Chilean domestic ceramic samples from Caleta Vitor (n = 38) and clay samples (n = 15) from nearby valley, coast and highland contexts. This study presents the first NAA data set of ceramics spanning a temporal period of 1500 years (c.2000 to c.476 bp ) from the Vitor Valley as well as the first attempt to use NAA to characterize potential clay sources in the region. On the basis of this study, we argue that the majority of domestic ceramics from Caleta Vitor share compositional similarities with clay samples collected from nearby valleys, allowing us to infer that the Caleta Vitor populations primarily procured their clay for domestic ceramics from local sources throughout a 1500‐year period. Thus, despite the fact that there were inter‐regional interactions during this period that included the influence of powerful Andean polities, it would appear that domestic ceramics continued to be produced locally, and by implication it can be argued that such interactions did not substantially affect this sphere of material culture production. Further, the apparent continuities in domestic ceramic production allow us to reflect on local decision‐making processes throughout the cultural phases considered in this research.     

Characterization of archaeological obsidians from Lagartero, Chiapas Mexico by PIXE

Obsidian samples from the archaeological site of Lagartero, Chiapas, Mexico and other samples from Mexican and Guatemalan sources were analyzed by proton induced X-ray emission. Statistical treatments such as principal-component analyses were applied to the data set. Obsidians from Lagartero were identified as coming from two obsidian sources in Guatemala and one in Mexico, thus indicating that there was contact between people of Lagartero and other Mayans or Mesoamericans.     

Obsidian types from Holocene sites around Lake Turkana,and other localities in northern Kenya

Obsidian has been widely used by early Holocene hunter-gatherers and succeeding Pastoral Neolithic peoples in northern Kenya. Here we report the results of over 2000 electron microprobe analyses of artifactual and non-artifactual obsidian from the greater Lake Turkana region. Of the 15 compositional types of obsidian observed, a preponderant type is widespread across the region from the Barrier in the south to Ileret in the north and east as far as Kargi. This obsidian is the principal type at Lowasera and most Pastoral Neolithic sites, including the Jarigole Pillar site and Dongodien (GaJi4). The source of this obsidian is not known, but based on its distribution the source may be located on the Barrier or in the Suguta Valley immediately to the south of Lake Turkana. Although there are several possible sources of local obsidian identified for minor types, in stark contrast to the central part of the Kenyan Rift, major sources of obsidian available for artifact manufacture are not known in the Lake Turkana region. The lack of obsidian from demonstrable Ethiopian Rift and central Kenyan Rift sources, and the absence of obsidian with compositions found at the Turkana area sites in assemblages in the central part of the Kenyan Rift suggests that the earlier Pastoral Neolithic peoples around Lake Turkana interacted with each other, but perhaps not as strongly with people farther south along the Rift Valley, even as herding practices were expanding to the southward into central Kenya.     

POST-COLONIZATION INTERACTION BETWEEN VANUATU AND FIJI RECONSIDERED: THE RE-ANALYSIS OF OBSIDIAN FROM LAKEBA ISLAND, FIJI*

PIXE–PIGME analysis of 19 obsidian artefacts from Lakeba Island in east Fiji identified contact with northern Vanuatu in the post-colonization period ( c. 2500–1000 bp ) of Fiji. The Lakeba obsidian is the only physical evidence for interaction across the 850 km water gap separating the archipelagos of Vanuatu and Fiji in the first millennium ad . New research on the Vanuatu obsidian sources with laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) casts serious doubt on the validity of a long-distance inter-archipelago connection in the post-Lapita era. This paper presents the re-analysis of 18 obsidian artefacts from Lakeba using LA–ICP–MS and radiogenic isotope results that demonstrate that the Lakeba obsidian is not from Vanuatu, and it most likely derives from the Fiji–Tonga region. Geochemical evidence for long-distance interaction and migration between the West and Central Pacific in the post-Lapita era has yet to be identified.     

Sources of archaeological dacite in northern New Mexico

For years archaeologists in New Mexico, particularly in the northern Rio Grande region have noticed a very fine-grained what appeared to be mafic or basalt raw material source in late Paleoindian and Archaic contexts in northern New Mexico and southern Colorado. Indeed, a number of Folsom, Cody, Plainview, and Archaic bifaces are produced from this material. It appeared that there were at least two possible very fine-grained volcanics that could be the sources for these raw materials – San Antonio Mountain in far northern New Mexico, in the Taos Plateau Volcanic Field, and Cerros del Rio, on the east side of Bandelier National Monument right above the Rio Grande. After reconnaissance collections at the two probable sources, the short story is that the vast majority of “basalt” artifacts were indeed produced from one of these sources, but they are petrologically dacite and silicic volcanic rocks. An additional dacite source, called here the “Newman Dome”, also in the Taos Plateau Volcanic Field was discovered in the 1980s, but remained mainly discussed in the gray literature by CRM archaeologists. Examination of various Paleoindian and Archaic collections from the northern and middle Rio Grande indicates a strong preference for this silicic rock for the production of chipped stone tools, and in concert with obsidian source provenance studies has increased our ability to reconstruct procurement and range in these preceramic periods. These high-alkali dacite sources are easily discriminated with their trace element compositions, and based on this study, procurement seems to be dominantly restricted to these three sources in the region. Here I discuss the petrology, geochemistry, and some of the archaeological issues of these sources and their utility in the Southwest archaeological endeavor in an effort to bring these important prehistoric raw materials into the published realm.     

Characterisation of obsidian subsource variability at El Paredón,Mexico

Portable X-ray fluorescence (pXRF) geochemical analysis on obsidian from five Formative period (1200 BCE to AC 100) sites from Tlaxcala, Mexico, has revealed that most of the material had similar values to those found in the closest obsidian source, named El Paredón, Puebla. Nevertheless, initial analyses did not resolve whether these materials came from the same caldera or from a specific obsidian deposit. Here we present a methodology that allows the identification of obsidian subsources. The results reveal that Tlaxcalan populations took advantage of a specific obsidian deposit called Tres Cabezas, Puebla, providing valuable new data to identify associated regional exchange networks.     

Obsidian procurement,least cost path analysis,and social interaction in the Mimbres area of southwestern New Mexico

For over 15 years chemical compositional analyses of obsidian artifacts recovered from archaeological sites in the southwestern United States have been increasingly used to address many research agendas. Despite this increasing interest in obsidian studies, few have attempted to synthesize the ever-growing amount of data generated from the numerous projects being conducted in the southwest. Here, we synthesize and present data for 923 sourced obsidian samples recovered from over 80 archaeological sites in the Mimbres area of southwestern New Mexico. We then use least cost path analysis as a means of investigating procurement patterns as well as networks of social interaction within the region.