Research archaeologist Dr. Daniel Pierce of the Bernice S. Warren Center for Archaeological Research (CAR), has published his findings on Aztatlán culture in a new book from University of Utah press.

Edited by Michael D. Mathiowetz and John M. D. Pohl, “Reassessing the Aztatlán World: Ethnogenesis and Cultural Continuity in Northwest Mesoamerica” presents the work of leading West Mexican scholars. The book provides a broad perspective of Aztatlán culture through a variety of different studies, Pierce said.

Pierce’s chapter, “Obsidian Usage and Trade in Postclassic West Mexico,” examines the Aztatlán culture’s obsidian trade. Obsidian is a volcanic glass used to make stone tools such as blades, knives and spear points.

“This book has been in the works for nearly a decade, so it is exciting that it has finally seen the light of day,” Pierce said. “I think it will be the go-to text for anyone interested in West Mexican archaeology, as it is the first volume of its kind.”

The book was published in 2024.

Examining Aztatlán culture

According to Pierce, scholars believe that Aztatlán society, especially its trade activity, helped shape Mesoamerican culture in the American Southwest, including religion, culture and exotic goods.

“The Aztatlán culture of West Mexico dominated western Mexico during the Post Classic period (AD 900-1350),” Pierce said. “Though it is less well known than other Mesoamerican cultures, the Aztatlán were seemingly the link that connected the great cultures of the American Southwest with those in Mesoamerica.”

“They even brought things like chocolate and macaws into the deserts of the southwest,” he added.

Research identifies unusual obsidian source

Pierce’s essay delves further into the use of obsidian in Aztatlán tradition, especially in trade activity.

“The Aztatlán people are well known for their long-distance trade networks,” Pierce explained. “It is no surprise that my studies have identified obsidian was being brought in from multiple different sources. But not only was the obsidian brought from various sources — some of which were hundreds of kilometers away — but each source was used differently.”

But more importantly, Pierce identified an unusual source of obsidian in West Mexico.

“Probably the most surprising thing was the identification of obsidian from a source called Sierra de Pachuca,” he explained. “This source is located all the way in central Mexico, just northeast of modern-day Mexico City.”

Obsidian from the Sierra de Pachuca region exists all across Mesoamerica and, rarely, in the United States, according to Pierce.

“My study was the first to have ever identified Pachuca obsidian in West Mexico,” he said.

Chemical makeup leads to discovery

Pierce explained that obsidian’s unique chemical properties can help pinpoint its location source.

“One thing about obsidian that I found particularly interesting is that we can discover precisely where the piece originated,” he explained. “The chemistry of the artifact will match the chemistry of the specific volcano and flow that it was collected from.”

“If we find an obsidian artifact at a site, through various types of analysis, we can discover exactly what volcano it came from even if it is hundreds of miles away,” he continued. “This gives us some really cool insight into the people of the past regarding trade, alliances and even migration.”

Identifying unique sources of obsidian led to Pierce’s discovery of Pachuca obsidian in West Mexico. This illustrates the far-reaching influence of Aztatlán trade activity.

Undergraduate study fueled passion for West Mexico

Piecre grew interested in western Mexico archaeology as an undergraduate student. His focus on obsidian as a research topic stemmed from his time working on a site named Chacalilla.

“With that excavation, I fell in love with area and its history. I spent the next decade working in the area focusing on obsidian, eventually including ceramics as well,” he said.

“Obsidian in particular is such a neat material to work with,” Pierce added. “It originates from volcanic flows, so it is only found in certain parts of the world. But where it is found, people in the past used it to make blades, knives and weapons, as well as all sorts of other useful tools.”

Pierce noted the degree of obsidian’s cultural influence as well.

“It even had social, political, economic and spiritual significance, with some obsidian being associated with the rain god Tlaloc, for example,” he said.

Scholarship explains significance of Aztatlán society

Pierce and other West Mexico scholars argue that the region’s archaeology has been ignored for too long.

“West Mexico lies in this sort of middle ground between Mesoamerica and the American Southwest, not just geographically, but also culturally,” Pierce said. “It is only in the past 10-15 years that the importance of this region is really beginning to become apparent. It now appears to be the link connecting the two areas.”

“Understanding West Mexico archaeology – and more specifically the Aztatlán culture – can provide important insight into the development of southwestern cultures. It also provides some answers as to why there are some similarities between the Central American cultures and those from borderlands,” Pierce said.

“This book is the first of its kind in that it focuses specifically on the Aztatlán culture,” Pierce said. “In this regard, it will be a must-read for anyone interested in understanding this culture so critical to cultural development in the New World.”

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