The collapse of the Mayan civilizationwhich took place between the IX and the 10th century AD, is one of the great mysteries of history. Today, a new and extraordinary testimony from the peninsula of Yucatánin Mexico, throws a very powerful light on those events. It is not an ancient text or an archaeological find, but one stalagmite: a natural climatic archive that recorded, year after year, the chronicle of a succession of droughtone of which lasts 13 consecutive years.
A research, conducted by an international team led byCambridge University and published in the magazine Science Advancesanalyzed a stalagmite, baptized “Tzab06-1“, Taken from the cave GROTAS TZABNAHlocated a short distance from large Mayan centers such as Uxmal And Chichén itzá.
The Stalagmite that tells the rain (and its absence)
As a tree grows for rings, a stalagmite is formed for layers of calcite deposited by the water that drips from above. Analyzing the isotopes of oxygen (O18) present in every single layer, scientists have been able to reconstruct the amount of rainfall fallen in a certain period.
The real turning point of this study, however, is its unprecedented temporal resolution. The researchers managed to obtain sub-annual data, that is, distinguishing between the rainy season and the dry one for each individual year between 871 and 1021 AD. This detail is fundamental, because for an agricultural civilization such as the Mayan one, based on the cultivation of corn, it did not count both the average annual rain, as its presence (or absence) during the season of growth of crops.
The results are impressive: in a span of 150 years, Stalagmite recorded eight periods of extreme drought during the wet season, each lasting three or more years. The most catastrophic event was an uninterrupted drought that lasted from 929 to 942 AD, a 13 -year period that exceeded any other similar event recorded in the history of the region for duration.
The impact on Mayan cities: different answers, same fate
By comparing this high precision climatic calendar with archaeological testimonies, the framework of the Mayan collapse becomes much more clear. The different cities-state did not collapse together, but showed different answers to climatic stress.
In the PUUC regionwhere the magnificent Uxmal stood, civilization depended entirely on artificial cisterns and basins for the collection of rainwater. Archaeological dates show that the end of the construction of monuments and hieroglyphic inscriptions in this area, around the early 900 DC, coincides with a series of close droughts recorded by Stalagmite. The subsequent, devastating 13 -year drought probably contributed to giving the coup de grace to an already extremely infragized political and agricultural system.
More east, the powerful Chichén itzá He showed a greater resilience. Although one of his oldest part (“Old Chichén”) declined in conjunction with the first droughts, the “New Chichén” managed to recover and thrive in a later period, between 942 and 1022 AD, characterized by less frequent droughts and different humid periods. Its strength probably resided in a different political-economic system, based on a vast network of taxes and trade that could mitigate the effects of a bad local harvest.
However, not even the powerful Chichén Itzá was invincible. His final decline took place at the beginning of the 11th century, coinciding with a post-classical “megadrought” (mega-science) that marked the end of an era.
