At an excavation site in northern Mexico, BYU archaeology students and professors recently discovered artifacts that have been buried for 1,000 years, including pottery sherds, hammer stones, maize kernels and — intriguing at a location 250 miles inland — a shell bead from the Pacific Ocean.
The site known as Casas Grandes, also called Paquimé, was a large ancient city that peaked between 1200 and 1400 AD. The site draws archaeologists worldwide to analyze its unique blend of cultural influences, with evidence (like the seashell) suggesting interactions between the Paquimé and distant peoples. For the past 10 years, a BYU team has studied a lesser-known time, the Viejo period, which predates the main era of Casas Grandes.
“We’re really trying to get at what we call the roots of Casas Grandes,” said BYU archaeology professor Mike Searcy. “There’s a connection between the large city of Paquimé and the site we’re excavating. For some reason the people returned to build yet a bigger city. What brought about this rise of not only a larger population, but the largest city center in the deserts of northwest Mexico?”
In the small farming hamlet just south of Paquimé that the team excavated, a site they named “San Diego,” the group uses pickaxes and shovels to dig long trenches, looking for traces of old structures or trash pits as clues for where to dig wider and deeper. In 2019 they uncovered the floor of the largest known communal structure from the Viejo period, a 9-meter-diameter building big enough to house 30 to 40 people.
“Every shovel full of dirt that we pull out is providing new data on the ancient people who thrived in the desert,” Searcy said. From the site, the group has learned about the resilience and ingenuity of the people living at the San Diego site, including the settlement’s organized building efforts to construct the communal structure.
“The communal structure that we excavated several years ago contained massive posts, two feet in diameter,” said BYU professor Scott Ure. “These were pine tree trunks. We think they probably came from the mountains nearby. Can you imagine cutting one of those down and carrying it all the way here? That required some agreement in the community to work together.”
Such details may hold lessons for those attempting to thrive in difficult climates today. “You see how intelligent and incredible the people were to survive in this environment,” said archaeology student Emily Brown. “The goal of archaeology is to take something mysterious and unknown and make it familiar. You really have a lot of respect for the people when you see very closely what they did.”
The team has employed some advanced technology to document their discoveries, including robotic surveying instruments that map artifacts with millimeter-level precision, survey-grade GPS and unmanned aerial systems that take images of the site from the sky. Managing this technology is an important part of the students’ archaeological training.
Immersion in the culture — from collaborating with fellow archaeology students at the National School of Anthropology and History in northern Mexico on the excavation, to experiencing the food and language of the area — also adds depth to the students’ training that isn’t attainable on campus.
“I can sit in a classroom and talk about what it’s like to move dirt, but there is nothing better for a student than to find their first arrowhead or to pull out a piece of pottery with designs on it we’ve never seen before,” Searcy said. “It’s one of the pinnacles of experiential learning to be in the field with students and watch them make discoveries.”