When a society experiences a collapse, political authority becomes decentralized, large settlements often become abandoned, economic specialization decreases; and monumental building projects, artistic, and literary achievements slow drastically. The Rio Verde Valley, a coastal floodplain located in the region of Oaxaca in Southwest Mexico, experienced such a collapse at the end of the Terminal Formative period (150 BC to 250 AD). A period of decentralization followed, with regional centers becoming the main seats of authority throughout the region. My aim is to understand how this collapse affected residential population mobility in the lower Rio Verde Valley between the pre-collapse Terminal Formative and post-collapse Early Classic periods. I seek to answer the question: could this political collapse have caused intra-regional migration amongst the people of Ancient Oaxaca? To answer this, I analyzed the stable 18O and 13O isotopes in a set of 21 samples of human long bone excavated from the Terminal Formative archaeological site of Yugüe and the Early Classic site of Charco Redondo. Oxygen isotope analysis is based on the principle that bone apatite and tooth enamel hold traces of oxygen isotopes found in the water that people drink, and that varying values of those isotopes reflect that the water was obtained from different sources. Based on literature surrounding the process of political collapse in ancient Mesoamerica and beyond, I expected to find evidence that intra-regional population mobility increased after the Terminal Formative period collapse. Instead, I found evidence of little to no mobility in both the Terminal Formative period site and the Early Classic period site, showing that the political collapse likely did not affect intra-regional mobility. These findings provide valuable insight into how human migration patterns correspond with political changes, both in the archaeological record of past civilizations and in modern societies.

Thesis Completion




Thesis Chair/Advisor

Barber, Sarah B.


Bachelor of Arts (B.A.)


College of Sciences



Degree Program



Orlando (Main) Campus



Access Status

Open Access

Length of Campus-only Access

3 years

Release Date