The archaeological site of Tlapacoya is a multicomponent settlement located on an island in a precolumbian lake at the foot of the Tlapacoya volcano, in the central southern Basin of Mexico. Its earliest noncontroversial occupation dates to about 1500 BC, and perhaps a couple of hundred years earlier.
Tlapacoya has been occupied pretty much continuously ever since; the settlement during the Early and Middle Formative period is one of the earliest agricultural settlements in the Basin of Mexico. The site has clear evidence of Olmec contact.
Tlapacoya also two localities that have possible preclovis occupations, where presumed hearths were excavated by Lorena Mirambell and Jose Luis Lorenzo in the 1960s and 1970s. Radiocarbon dates on the preclovis Tlapacoya occupations are 24,000+/-4000 and 21,700+/-500 years BP, and an obsidian hydration date on a blade returned a date between 21,250 and 25,000 years before the present.
The earliest occupations at the site remain controversial, because of the varied dates associated with the volcanic tephra.
Ortega-Guerreroa, Beatriz and Anthony J. Newton 1998 Geochemical Characterization of Late Pleistocene and Holocene Tephra Layers from the Basin of Mexico, Central Mexico. Quaternary Research 50(1):90-106.
Nichols, Deborah. 2001. Tlapacoya (México, Mexico). pp. 757-758 n Archaeology of Ancient Mexico and Central America: An Encyclopedia, Susan Toby Evans and David L. Webster, eds. Garland Publishing, Inc. New York.
Thanks to Dar Habel and Jacques Cinq-Mars for current data on Tlapacoya. Lorenzo and Mirambell have published several papers on Tlapacoya, the latest one (1999) a chapter in the book Ice Age Peoples of North America, edited by Rob Bonnichsen. This glossary entry is part of the Dictionary of Archaeology.