Xcoch and Puuc Archaeology Project


The Xcoch and Puuc Archaeology Project, directed by Dr. Ezra Zubrow, is an investigation dealing with climate change, and how civilizations in the Yucatan have adapted to it. The Classic Maya collapse, which occurred between 800 and 900 AD, is of particular interest to researchers delving into this time period. The current change in global temperature if also of great importance to researchers today, as current weather patterns suggest that it is remarkably substantial to the Medieval Warm Period, which occurred around the same time as the Classic Maya collapse. Please take the opportunity to explore our project through the materials provided on this website. Any questions or comments about the project or website may be directed to the appropriate personnel on our Contacts page. Thank you for visiting.


I. Introduction

Research into climate change and human response at the ancient Maya center of Xcoch and the Puuc region of Yucatan, Mexico (Figure 1) has been underway since 2009. The phenomenon known as the Classic Maya collapse (800-900 AD) has intrigued and befuddled researchers for decades. This time period is especially relevant to Arctic researchers because it coincides with the Medieval Warm Period (AD 800-1300), when climatic conditions enabled Norse peoples to explore and colonize the North Atlantic Islands and reach the shores of America long before Columbus (Dugmore et al. 2007; McGovern et al. 2007) How Arctic climate change affected processes of cultural development and decline in the North Atlantic and Maya Lowlands has the potential to inform us today regarding the far reaching and serious cultural-environmental impact of global climate change.

Climate change in the Arctic had potential cultural consequences for many past human societies, even those far from northern Polar Regions. During a relatively warm period of the North Atlantic Islands, the Vikings of the Medieval Warm Period (AD 800-1300) were able to colonize Iceland and Greenland and even explore parts of North America. Their adaptation to this natural environment was made possible by their traditional dairy farming economy as well as hunting and fishing and international trade in exotic goods (Dugmore et al. 2007). By 1400, this adaptation changed with rapid climatic change at the onset of the Little Ice Age, which made their social adaptations difficult to sustain forcing Norse culture to retract and abandon this area altogether, though Inuit cultures thrived in these environmental conditions until recently (McGovern et al. 2009; Dugmore et al. 2009).

Near the beginning of the Medieval Climatic Optimum (AD 800-900), the Maya Lowlands, 7000 km to the south, were experiencing severe disruptions to rainfall patterns leading to sustained periods of drought (Gill 2000; Hodell et al. 2001). For an advanced civilization that was heavily populated and dependant on agriculture, such drying conditions must have contributed to agriculture decline, endemic warfare, reduced trade, and eventual cultural collapse for many lowland Maya centers. How Arctic climate change affected processes of sociocultural development and decline in the North Atlantic and as far away as the Maya Lowlands over a millennium ago has the potential to inform us today regarding the far reaching and serious cultural-environmental impact of global climate change. To understand the complex effects of Arctic climate change requires collecting a wide range of climate and archaeological data from both tropical and Arctic regions, including key Maya centers in the Puuc hills region of the Northern Lowlands of Yucatan, Mexico Climate change has long been seen as a major factor in the decline of ancient Maya civilization. Prolonged cycles of drought affecting agriculture and available drinking water in particular are believed to have being critical in the phenomenon known as the Classic Maya collapse beginning around the 9th century AD. Only recently, however, have Maya researchers begun to contemplate other Maya collapses including evidence for a severe drought occurring between the Preclassic to Classic Maya transition around the 2nd century AD. The role of the climate change involving periods of abundant rainfall and drought cycles were also key factors in the origins and development of Maya culture. These factors are especially relevant in the Northern Maya Lowlands where drought cycles were commonplace and dry seasons could be unpredictably long and precarious even under the best environmental conditions. The correspondence of Arctic warming in early medieval times and the expansion of the Vikings to Iceland and parts west was clearly not coincidental. At this time during this same warming trend, the Southern Maya Lowlands were experiencing severe drought conditions that eventually led to large-scale social disintegrations. Interestingly, some sites in the Puuc hills region of the Northern Lowlands underwent a brief florescence for a century or so before they too succumbed to the effects of climatic warming, prolonged drought, and attendant settlement abandonment. How did the Maya in the North, which is more prone to drought and subject to less rainfall than the South, delay collapse so long (there is no significant surface water in the Puuc region)? Increased tropical cyclonic activity may have been a factor since Yucatan is located on a notorious hurricane path. Warming Atlantic waters including those in the Caribbean Basin provide the raw energy for tropical cyclones caused, in part, by melting Arctic ice caps, warming sea water, and changing ocean currents. These conditions can produce more frequent and more severe storms bringing unpredictable yet heavy rains (and damaging winds) that were sometimes detrimental for sustained agriculture.

Constructing and expanding hydraulic systems of rainwater capture including reservoirs (aguadas) and underground water cisterns (chultuns) by labor-intensive means for water storage to capture periodic but torrential rainfall from tropical storms and hurricane events could have been a short-term strategy employed by some Puuc Maya for local irrigation agriculture and replenish local drinking water supplies. Openings to the subterranean water table such as at deep caves contexts would have been at a premium given that so few are known for the Puuc region.

The aguada zone south of Xcoch, for example, shows preliminary evidence of possible irrigation canals associated with ponding features in a rich agricultural zone of modern farm fields near the town of Santa Elena (Smyth and Ortegón 2008). Irrigation and the long-term storage of surplus production (maize, beans, squash, and chili peppers; Smyth 1989, 1990) could have been local responses to changing rainfall patterns brought on by rapid global climate change. These adaptive strategies, however, would have only delayed the inevitable in the event of prolonged drought caused by rapid climate change. Water storage intensification and changing patterns of rainfall are being reconstructed by systematic sampling of aguadas and caves at Xcoch and elsewhere in the Puuc region. A global cultural comparison of adaptation is how the Greenland Vikings in the 1300s responded to the cooling Arctic temperatures of the Little Ice Age by shifting their diet from agricultural produce to food from the sea (Richardson 2000), but cooling forced their eventual abandon of this area altogether.

I-B. Location

The Puuc is a Mayan term that literally means “hills.” Located in the northwest portion of the Yucatan Peninsula, Puuc but has several other meanings such as: 1) a geographic area 2) an archaeological region 3) an architectural style and 4) a period in the history of the Maya. The Puuc contains two physiographic zones covering an area of 2,861 km² for the state of Yucatan: a northwest-southeast trending ridge system approaching 100 m in height (Sierrita de Ticul) with an area of low hills and bedded limestone south of the ridge system (Santa Elena District), and an extensive zone of cone karst hills (Bolonchen District). Within these zones are found the archaeological Puuc sites of Uxmal, Kabah, and Labná and the centers of Sayil, Chac and Xcoch which are the subjects of the proposed research. The Puuc proper or Santa Elena District forms the northernmost component of the central hill system. The ridge appears to be the result of down-to-the-basin faulting associated with uplift and Eocene emergence of the peninsula. Sedimentary deposits along the north edge of the ridge suggest that it may have functioned as a Miocene shoreline (Weidie and Ward 1976). The strata of the Santa Elena District and the Sierrita itself consist of massive beds of fossiliferous, reddish Eocene limestones (Dunning 1992).

The water table in the Santa Elena District lies up to 65 m in depth while in the Bolonchen District, depth to ground water may reach 100 m below the surface. The Prehispanic Maya did not have the technology to penetrate the various bedrocks layers to artificially access the water table. The uppermost bedrock layer is a residual indurated caprock underlain by a layer of soft marl known as sascab and both can vary considerably in thickness ranging from about 10 cm to over 1.5 m (Isphording and Wilson 1973; Dunning 1992). The variability of caprock and sascab were extremely important for prehispanic settlement in the region. Because of the long winter dry season and the lack of permanent natural water sources, the Maya penetrated the caprock and excavated the soft lime marl creating subsurface cisterns (chultuns) to store rainwater during the summer rainy season. Hundreds of such chultun features are known for the sites of Sayil, Chac, and Xcoch as well as elsewhere in the Puuc region. Other important water features include clay-lined dry sinks (aguadas) and deep cave systems; there are no sinkhole (cenotes) in the Puuc region proper but there are a number of them a short distance north of the Puuc ridge. Aguadas are more common in the Puuc region but there are only three deep cave systems have been documented as reaching the permanent water table: Gruta Xcoch, Gruta de Chac, and Gruta de Xtacumbilxunam (E.W. Andrews IV 1965; Matheny 1978; Mercer 1896; Smyth 2000; Smyth and Ortegon 2008; Stephens 1843).

I-B. 1. Climate

The Puuc region and much of northern Yucatan is characterized by a Tropical/Dry Winter Koeppen climate type with an average temperature of about 18° C and a pronounced winter dry season. The major controls on climate affecting seasonal rainfall are the peninsula’s latitude, low elevation, its flat terrain, and the warm waters that surround it, high atmospheric pressure over the Atlantic, and the prevailing easterly trade winds (Vivo Escoto 1964). During the dry season lasting, from November through April , a southwestward shift of the Atlantic High produces descending air aloft reducing the cloud formation through evaporation of cloud moisture and the interruption of rainy season convection patterns. In the summer and fall months (May through October), the peninsular lies directly in the path of the easterly trade winds. There is a daily buildup of thunderstorms that are carried westward by the trade winds. Mean annual rainfall in the Puuc region is around 1100 mm, though variation in long-term annual average can be as high as 30 percent (Wilson 1980). The rainy season usually yields two periods of rainfall maximum: late June to early July and early to mid September. Between these two peaks is a period of variable rainfall locally referred to as the canicula. During drought years, the canicula can be severe with little or no rainfall from mid-July to mid- September. Under these conditions, maize crops that are not irrigated will be lost (such as during the drought of 2009). Rainfall can be radically altered by tropical storms/hurricanes and winter dry season cold fronts known as nortes, which are breakouts of polar air masses from North America that reach the Yucatan peninsula and bring lower temperatures, overcast skies, windy conditions, and sometimes rain. Yucatan lies on one of the most frequent tropical storm tracks arriving between August and October. Such storms bring high winds, tornados, and heavy rainfall and can have devastating impacts even at interior locations. Category 5 Hurricane Gilbert in 1988 and Category 3 Hurricane Isadore in 2002, for instance, destroyed 90 percent of the maize crop across large areas of the Yucatan including the Puuc region.Indeed, there is growing evidence that past the climate of the Yucatan Peninsula has varied greatly over the past 3000 years (Covich and Stuiver 1986; Dahlin 1983, 1986; Dahlin et al. 1992; Folan 1985; Folan et al. 1983; Messenger; 1990; Hodell et al. 2001; Haug et al. 2003; Lozano-Garcia et al. 2007; Mueller et al. 2009; Webster et al. 2007; Moyes et al. 2009). Located near the northern edge of the Intertropical Convergence Zone, the Northern Maya Lowlands have been particularly effected by global climate changes and resultant patterns of rainfall impacting agriculture and domestic consumption.

I-C. Archaeological History

Modern research at the Puuc region sites of Sayil, Chac II, and Xcoch began at Sayil with the mapping of the site’s large monumental architecture by Edwin Shook in 1934 and 1935. Rubert and Smith (1957) made a brief visit in 1953 to map the floor plans of several house structures. Pollock’s (1980) impressive architectural survey of the Puuc included the collection of information from several major buildings ay Sayil, While George Andrews (1975, 1985) later surveyed, updated, and extended many of Pollock’s characterizations of Sayil’s standing buildings. Mexican archaeologists have undertaken numerous building consolidations at Sayil, Including Ramon Carrasco’s and Sylviane Bouchers’s (1990) architectural excavations at the Great North Palace and Lourdes Toscanos recent stabilizations in 2009.

Sabloff, Tourtellot, and colleagues (1982-1989) initiated a comprehensive site-focused study of settlement patterns at Sayil. This project documented and sampled architecture by intensive mapping (Phase I), and limited surface collection, excavation, and soil testing (Phase II), producing a detailed site map covering 3.5 sq km of the site’s architectural remains. These studies defined many of the settlement boundaries of Sayil proper, documented considerable architectural variability and revealed the presence of significant architectural and nonarchitectural surface and soil patterning (Carmean 1991; Dunning 1989, 1991, 1992; Killion et al. 1989; Sabloff et al. 1984, 1985; Sabloff and Tourtellot 1991; Tourtellot et al. 1988, 1989; Tourtellot and Sabloff 1993). In 1990 and 1992, Smyth and Dore directed systematic surface survey and soil testing (Phase III) at the site-scale to reconstruct community activities and aspects of site organization at Sayil. Employing methods of large-scale surface collection, data on surface artifacts and soils were sampled from all settlement contexts, architectural and nonarchitectural. Phase II of the Sayil Project explored urban phenomena and northern Lowland Maya adaptations to semi-arid tropical environmental conditions (Smyth and Dore 1992s, 1992b, 1994, Smyth et al. 1995).

Field research at Chac (II), located 1.7 km northwest of Sayil, began as an outgrowth of the surface collection survey at Sayil. In 1995, a program of intensive survey at Chac included settlement mapping, systematic surface collection, and soil testing. It became immediately apparent that Chac was an independent settlement and the survey documented a dense settlement area covering 3 sq km. In 1996-2003, a large program of architectural excavation and consolidation at the Chac Pyramid Plaza and the Central Acropolis was undertaken to reconstruct the site’s architectural chronology that now begins in the Early Classic period. In addition, test pitting across the site and horizontal exposures of two large residential compounds took place to behavioral reconstruct nonelite architecture and domestic activity patterns and results show evidence for foreign intrusions at the site. In addition, the nearby Gruta de Chac (I) was opened, explored, and sampled including the mapping and test excavation of its related settlement and it was determined that Chac water cave and the Chac (II) site were one and the same site (Smyth 2000).Work at the site of Xcoch, located between the town of Santa Elena and archaeological zone of Uxmal, began in 2006 and remains ongoing. Mapping survey and surface collection now cover more than 1 sq km, though the entire site may extend over an area of 6 sq km. A program of test excavations has sampled most of the surveyed areas of the site as well as numerous water features such as aguadas, canals, and chultuns. Dating results show that Xcoch was a large settlement with huge monumental architecture in the Middle Preclassic period and grow to its maximum size before being rapidly depopulated at the end of the Late Classic period. Exploration, mapping and sampling of the Xcoch water cave, located in the middle of the site, as well as another deep cave 11 km to the east (LaVaca Perdida cave) have produced speleothem and pollen core evidence of significant drought cycles at the end of the Preclassic and Late Classic periods that must have strongly impacted settlement occupation at Xcoch.

During Year 1 of the project, we will to organize and cross-reference the existing paleoecological datasets from eastern Kamchatka, and identify locations for new core samples. Archaeological investigations will drive the selection of paleoenvironmental sample sites. Bourgeois and colleagues have already collected cores near the proposed study area. In Year 2, we will begin our own survey of the paleoenvironment in the study area. In preliminary field and laboratory work carried out in 2007 and 2008, we recovered core samples from the main environmental contexts at both OFL and YLI. Affiliated researchers at McGill University are sampling and analyzing the cores for pollen and macrofossil content, and for isotopic variation. We will collect representative cores from bogs adjacent to archaeological sites in Kamchatka in order to correlate environmental changes with episodes of human occupation. These core samples will be collected using manual augers, or in difficult to penetrate locations, with a piston driven coring device. Core stratigraphy will be documented in the field, noting parameters such as Munsell color, mineral grain size (sand, silt and clay), abundance and quality of organic matter. Tephra layers will be noted and sampled, in order to date the strata. Cored sediments then can then subdivided for shipment to the laboratory. Sediments will be sampled at high resolution and analyzed for chemical composition, pollen, and macro-organics. We will use conventional palynological treatments: hydrochloric acid to dissolve carbonates, hydrofluoric acid to dissolve silicates, potassium hydroxide and acetolysis to remove the organic matter (Moore, et al. 1991). Macro-organics from those samples will be sorted to isolate identifiable plant parts to be sent for 14C dating by a contract laboratory.

II-E. 3. GIS Project

The GIS portion of this project will involve a regional settlement pattern analysis of Mayan sites in the Puuc region, a comparison of intrasite spatial analyses of artifact distributions from the sites of xcoch, sayil and choc, and the modeling of hydrology within the site Xcoch.

Regional GIS

The regional GIS of the Puuc region will examine the distribution and size of sites over time so that this development may be compared with environmental and climatic records from spelothem and pollen analysis.

Intrasite spatial analysis

Extensive systematic surface collection surveys have been completed over the past 20 years by Michael Smyth and his team. The data from these surveys includes ceramic and lithic count and attribute data from 3x3m collection squares. Sub-surface test units were also excavated throughout the sites of choc and xcoch. The ceramics are classified according to vessel type and ware type which provides the ages of the ceramic. The data will be subject to kernel density estimates and unconstrained clustering to determine the use of space across the sites over time and over the climatic sequence. These results will also be compared to the architectural maps to determine how well the structural remains compare to the activity distribution within the sites.

Hydrology modeling

The site of xcoch contains evidence of a significant hydrological system, including water catchment areas and irrigation canals, which would probably have been created to counteract the lack of rain during dry periods. We will create a detailed ground map of the site by taking close interval total station points in order to model the surface water flow.

GIS layers have been produced by integrating terrestrial models, archaeological datasets, and environmental datasets from YLI and OFL. The present proposal will incorporate data from the Kamchatka peninsula. The GIS portion of the Kamchatka project has already begun. The research team at the University at Buffalo is currently gathering GIS data and digitizing maps for Kamchatka. The three modeled and dated GIS projects will allow comparison of diachronic changes in these three regions, across three environmental-temporal periods. Spatial analysis of the changes in environment and society can help explain how changes in human technology, exploitation of resources and land use occurred in KRE, YLI and OFL. Included in the integrated GIS databases are both existing and new paleoenvironmental, archaeological, and terrain data for each of the study areas. These databases will be available on a dedicated website. The paleoenvironmental and archaeological data will be merged using ESRI’s ArcGIS in order to provide comprehensive models of the relationship between environment and prehistoric society at the regional scale. We will create archaeological and environmental layers for each of the regions from the three periods being examined. For the environmental layers, we will interpolate data from the pollen cores to estimate environmental zones. Interpolation is a process performed within GIS to predict values for a surface from a number of sample data points. The environmental layers will consist of polygons representing individual environmental zones and containing information on the environmental characteristics of the individual areas. The archaeological layers will consist of site locations, points in the landscape, and detailed information about materials recovered during excavation. If there are several related sites from one period we will create layers displaying network connectivity between sites. We will create regional models by combining several archaeological and environmental layers into a single map. Then we can generate predictive models of archaeological site locations based on known site locations or to simply estimate past land use over a landscape at a given point in time (Wheatley and Gillings 2002).

III. Broader Impacts and Intellectual Merit

The circumpolar North is often seen as an observatory for changing relations between human societies and environments. This project will help place the circumpolar North into wider contexts with its focus on climate, time and space, change and movement. As a coordinated program of research on the North it will enhance synergies between the social and natural sciences. This project has two broad impacts. One will be the far-reaching benefits of an increased understanding of human-environment interaction. We will disseminate the results of this research at conferences and in scholarly journals, and in an edited report which will bring together the various interdisciplinary sub-projects into a cohesive whole. This project will also support the education of undergraduate and graduate students, and will provide a context for the mentoring of post-doctoral scholars. The intellectual merit of this project is its interdisciplinary approach to a broad circumpolar comparison of human-environment interaction. The methods of paleoenvironmental, geological, and archaeological research reveal very specific types of information. In an interdisciplinary project, these small pieces of the puzzle will be assembled to create a detailed picture of changes in human culture and environmental conditions over time. ICAP is meant to become part of a larger archaeological research project known as the Global Archaeological Project (GAP). GAP, which is an initiative of the University of Cambridge and the University at Buffalo, will utilize data from the three subarctic points of YLI, OFL, and KRE, to compare with data from three points in the temperate zone, and three points in the tropical zone. Among the archaeologists who have expressed a desire to participate in GAP are Graeme Barker, head of archaeology at the University of Cambridge, Martin Jones, also of the University of Cambridge, Peter F. Biehl of the University at Buffalo, who supervises work on the western mound at Catalhoyuk, and Francoise Audouze of the Centre National de la Recherche Scientifique in Paris.


GIS Methods

The GIS portion of this project will involve a regional settlement pattern analysis of Mayan sites in the Puuc region, a comparison of intrasite spatial analyses of artifact distributions from the sites of xcoch, sayil and choc, and the modeling of hydrology within the site Xcoch.

Regional GIS

The regional GIS of the Puuc region will examine the distribution and size of sites over time so that this development may be compared with environmental and climatic records from spelothem and pollen analysis.

Intrasite spatial analysis

Extensive systematic surface collection surveys have been completed over the past 20 years by Michael Smyth and his team. The data from these surveys includes ceramic and lithic count and attribute data from 3x3m collection squares. Sub-surface test units were also excavated throughout the sites of choc and xcoch. The ceramics are classified according to vessel type and ware type which provides the ages of the ceramic. The data will be subject to kernel density estimates and unconstrained clustering to determine the use of space across the sites over time and over the climatic sequence. These results will also be compared to the architectural maps to determine how well the structural remains compare to the activity distribution within the sites.

Hydrology modeling

The site of xcoch contains evidence of a significant hydrological system, including water catchment areas and irrigation canals, which would probably have been created to counteract the lack of rain during dry periods. We will create a detailed ground map of the site by taking close interval total station points in order to model the surface water flow.


Ezra Zubrow, PhD., Principal Investigator
Dr. Ezra Zubrow is the principal investigator for the Xcoch and Puuc archaeological project and is the current director of the Social Systems GIS Laboratory at University at Buffalo.

Greg Korosec, M.A, PhD. Student
Greg is currently the Associate Lab Director, Social Systems GIS Laboratory, University at Buffalo. His research interests include GIS, landscape, resilience, geoarchaeology, the Russian Far East, Neolithic Northern Finland, and CRM.

Dustin Keeler, PhD.
Dustin is a post-dcotoral researcher at the Social Sytems Gis Lab at the Unibersity at Buffalo. His research centers on Upper Paleolithic Western Europe, Neolithic Northern Finland and Kamchatka, Russia. He also maintains interests in regional settlement patterns and intrasite structure.

Michael Smyth, PhD.
Dr. Michael Smyth is a professor of Anthropology at Rollins College in Winter Park, Florida. Hhe focuses his work on Mayan civilization, and has led expeditions into the Yucatan for over 20 years. Dr. Smyth’s most recent field work is at Xcoch in the Yucatan, and has been a great contributor to projects being carried out by Dr. Zubrow’s team.


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