Unlocking the secrets of ancient Mexico

RIT researchers use spectral imaging technology to study past culture

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The state of Oaxaca in southern Mexico has a 10,000-year history of human occupation. It was the center of ancient Mexico’s prominent Zapotec state, and its descendants still occupy the region today. Due to this rich history, the area has been a center for archeological and anthropological study and fieldwork for decades.

Now, a multi-university, multidisciplinary research team, including RIT faculty and students, is uncovering new information about the kingdom’s origin and ultimate decline, and producing the most comprehensive ecological information ever collected about ancient life in the region. 

“Oaxaca was a major political and economic center in ancient Mesoamerica, and the Zapotec people created the region’s first state-level society, featuring cities, a complete writing system and complex, interregional socioeconomic interactions,” notes Bill Middleton, professor and chair of the material culture sciences department at RIT. “Our project seeks to further enhance understanding of how the Zapotec people lived, worked and interacted with their environment while also providing a comprehensive record of how the region has evolved over the last 10 millennia.”

The team is using sophisticated imaging technology, through a partnership with NASA, to collect hyperspectral and multispectral images of the landscape and map modern floral communities and agricultural land use in Oaxaca. Teams of field workers are also using the imagery to more accurately assess local environments, allowing archeologists and paleo-botanists access to the most comprehensive database of contemporary land use and vegetation cover that currently exists for the state of Oaxaca. 

The data collected is then compared to sediment samples collected from ancient land surfaces, which are analyzed for plant microfossils, such as opal phytoliths and pollen, and used to reconstruct ancient environments and interpret how the region’s landscape has evolved over time and the human impact on that evolution. 

“Hyperspectral technology, which can image over 240 colors or channels of spectra, is allowing us to record and collect high-quality data on a wide area, over 30,000 square kilometers in total,” says David Messinger, director of RIT’s Digital Imaging and Remote Sensing Laboratory and a member of the research team. “This allows us to create the most comprehensive picture of current and past land use, environmental degradation and landscape evolution ever developed for southern Mexico.”

The team’s preliminary findings indicate that periods of human stability actually enhanced landscape stability and prevented degradation, greatly contrasting modern views on human impacts on the environment.

“Our partners at the University of Colorado at Boulder have found that during the long Zapotec reign, which lasted for close to 1,000 years, there was tremendous stability in the region’s patterns of soil erosion,” says Middleton. “It was only when the empire crumbled that serious environmental degradation occurred. This seems to show that prehispanic landscape management actually improved the environment even where large human populations existed. The satellite data will allow us to expand these studies to a much larger region.”

Middleton, who returns to Oaxaca during winter quarter to continue ongoing fieldwork at several excavation sites, hopes the research can further promote current environmental preservation programs in Mexico, including efforts to protect native farmers and agricultural sites from development. He also believes it will shed new light on Zapotec society and its impact on modern Oaxaca, while adding to the overall body of knowledge on how the Earth has evolved over the centuries.

Over the last two years the research group has had a number of additional RIT collaborators, such as John Kerekes, professor of imaging science; graduate students Justin Kwon and Kelly Canham; and multiple undergraduates, including a team that traveled to Mexico with Middleton to conduct field work in 2008. Additional research partners include faculty and students from the University of Colorado at Boulder, Johns Hopkins University and Cornell University.