Lake Texcoco
Dr. Gonzalez also reconstructed the environment of Lake Texcoco around the time of Tepexpan Man by analyzing sediments and fossils from the area. Dr. Gonzalez and her team analyzed sand, clay, and volcanic ash, as well as fossils of diatoms (microscopic algae) and ostracods (a form of small crustacean). When Tepexpan Man was alive, the lake was very deep, full of fish, and surrounded by trees. The environment surrounding Lake Texcoco experienced major changes over the past 20,000 years including several volcanic eruptions, changing water levels, and numerous types of vegetation. These environmental changes clearly affected populations living in the area. Today, Lake Texcoco is almost dried up. It sits on the northeast outskirts of Mexico City.