The tropical coasts of Mesoamerica are lined with mangrove forests and estuaries that, while rich in many food resources, are of little use for agricultural production. As a result, once Mesoamerican people (forerunners of the Aztec, Maya, and other Native American groups of Mexico and Central America) became fully committed to agricultural subsistence, probably during the Middle Formative period (~800 - 400 BC), human habitation shifted away from the coasts. The coastal margins continued to be utilized for hunting, fishing, and shellfish collecting, but increasingly over time as well for industrial production. Salt extraction is one well-documented activity, and recent research has indicated that large-scale ceramic production was another such activity. To date, there have been very few systematic investigations of these coastal Mesoamerican industrial sites. There is some urgency to initiate such studies because sea-level rise and environmental degradation threaten to submerge or destroy coastal sites over the coming few decades.
The National Science Foundation has provided funds to support a three-year effort to document archaeological remains on one section of the Mesoamerican coast, the far-southern Pacific coast of Chiapas, Mexico, a region known as Soconusco. One fundamental issue that this NSF project will address is whether the boom and bust cycles posited for Soconusco are real or whether they may be artifacts of the coarseness of the existing chronological framework. By investing heavily in chronometric analysis (radiocarbon and luminescence dating) this project will dramatically improve chronological resolution. If demographic change still appears to be abrupt and cyclical once a better chronological framework is available, then it becomes sensible to begin evaluating possible causes of collapses, population explosions, and prolonged abandonments. Unlike the cases discussed by Jared Diamond in Collapse, all of the instances of 'collapse' and recovery listed above took place in a single region, so geography is held constant, and other possible causes of demographic change, such as climatic downturns or amelioration, population movements, local political events, and organizational or technological innovation, can be examined without the confounding effect of geographic variability.
Not only did prehistoric Soconusco people use the mangrove zone for industrial activities, leaving an abundance of archaeological remains, the zone itself acts as a catch basin for plant parts and charcoal brought down rivers and streams or blown in from the coastal plain. This means that changes in vegetation cover in the coastal-plain agricultural zone are recorded in sediments of the mangrove zone. Thus, while mangrove-zone archaeological remains document industrial activities that people engaged in away from their inland agricultural villages, the sedimentary record documents upstream land clearance, which correlates with population levels on the coastal plain. The archaeological and geo-archaeological research recently funded by NSF will sample and analyze these complementary historical records.
According to current archaeological understanding, the records targeted for investigation on this project were shaped by momentous changes that swept across Soconusco at various times during prehistory and history:
- The region was a center of pre-Maya sculptural art, but the sculptors abruptly closed up shop around 2000 years ago, and much of the coastal plain seems to have been abandoned. - Emissaries or militarists from the highland Mexican empire of Teotihuacan arrived around AD 400, apparently initiating a period of sustained population growth that lasted at least through Terminal Classic period (~AD 1000). - During the Terminal Classic, potters of the estuary zone produced Plumbate, the most technologically sophisticated and widely traded pottery every made in Mesoamerica. - Population appears to have collapsed again around AD 1100. - Late Prehistoric population resurgence began around AD 1250. - At the time of the Spanish conquest (AD 1521), Soconusco was the most distant province of the Aztec empire and paid tribute to the rulers of Tenochtitlan (Mexico City). - Population again plummeted soon after the conquest, as introduced European diseases decimated the population, a collapse from which it did not recover until the early 20th century.
The project will provide research opportunities for MA students at several California State Universities in the Los Angeles area and for Ph.D. students at Washington State University, SUNY-Albany, and UCLA.
