Climate change at Xcoch mapped in Mayan caves
Original article extracted from Past Horizons
SATURDAY, FEBRUARY 25, 2012 | ARTICLES, NEWS
Careful mapping and meticulous excavations at an ancient cave system in the Yucatan Peninsula, Mexico, are revealing the importance of the site to the ancient Maya – both for religious ritual and human survival.
The Xcoch Archaeological Project (XAP) is a long-term research programme studying the adaptation of the ancient Maya in the Puuc region of Yucatan, from their first appearance in the Preclassic until modern times. The Puuc was a major region of Maya culture during the pre-Columbian period. The project’s current focus is on past climate change and human responses, and a recent report by University of Cincinnati (UC), one of the project partners, shows a remarkable longevity in the use of the cave site as well as a story of drought and reactions to these climate events.
Nicholas Dunning, a UC professor of geography, says the cave, located in the ancient ruins of the city of Xcoch, was used continuously from at least 800 BCE until the 19th century, when it was still used for rituals.
The large city – featuring a great pyramid and other elaborate architecture – was built above one of the few cave systems in the region that penetrates the permanent water table. Mapping and excavations of the ancient city revealed a network of cisterns and reservoirs that fed the community’s water supply which grew and developed over time. The cave exploration discovered mounds of broken pottery and charred sacrifices, which also indicated the cave was a key religious site that involved worship of perhaps unsurprisingly, the rain gods.
Dealing with drought
“This is in a region that has no surface water,” says Dunning. “There are only a handful of caves that go deep enough to get to the permanent water table, so for any place that’s bone dry for five months out of the year, this is a pretty special location.”
Two large reservoirs are located in the middle of the city – next to the monumental architecture – and smaller reservoirs and cisterns extend into the residential area and surrounding farm land.
“The Maya built a stairway to the cave entrance that we have to crawl in to enter and look for stalagmites – cave formations,” says Dunning. “Since this is a seasonal climate, the stalagmites act in the way that tree rings do – recording the rainfall – because they only grow during a part of the year when there’s rain.”
Fieldwork pays off
The field work is far from glamorous. Entering the deep cave involves a good deal of crawling through long, narrow tunnels. The summer expeditions also involve working in hot, humid temperatures that can rise as high as 105 degrees.
It was back in 2009 that the project initiated a study designed to begin reconstructing climate change and the human responses over the past 3000 years, especially emphasizing the phenomena associated with so-called Classic Maya collapse (800-900 AD). This time period is very relevant to global climate 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 (Dugmore et al. 2007; McGovern et al. 2007). How climate change affected processes of cultural development and decline in the Maya Lowlands has the potential to inform us today regarding the far-reaching cultural-environmental impact of global climate change.
Understanding occupation and abandonment
The results through the 2010 season continued to show that Xcoch was a large Prehispanic Maya centre with long occupation dating back to the Middle Preclassic period (800-400 BCE), or earlier, and peaking in the Late Classic period (600-800 AD) before general abandonment of the site, though the deep water cave continued to be visited up until modern times. Archaeological data so far suggest that there were at least two periods of intense construction activity that correspond to episodes of drought.
Source: University of Cincinnati/NSF Report