ASU Research E-Magazine: Lost Beneath the Lake

ASU archaeologists excavated sites in central Arizona’s Tonto Basin for most of the 1990s. Analysis of their findings at those sites will take years. But the long-term Roosevelt Platform Mound study is providing a new understanding of the 13th century Salado civilization, about which very little was previously known.

Some results of all the digging can be seen at Pueblo Grande Museum and Archaeological Park in Phoenix. On display is a collection of artifacts representative of 261 dig sites in the Tonto Basin area surrounding Roosevelt Lake. Archaeologists refer to the prehistoric people who lived there as the Salado because the Rio Salado (Salt River) was the lifeblood of the basin.

Such a large and comprehensive excavation was necessary because of a plan (now completed) by the U.S. Department of the Interior’s Bureau of Reclamation to increase the size of the Theodore Roosevelt Dam. The renovated dam increased the size of Lake Roosevelt. Many important sites were lost beneath the water.

“This collection is especially interesting because it is so complete,” says ASU archaeologist Glen Rice. “Many of the sites we studied burned down and collapsed around A.D. 1370, and families were forced to leave all of their possessions inside.”

The ASU team was able to collect entire room assemblages, not just leftover trash. The collection includes all of the artifacts collected during excavations from 1989 to 1998.

During the course of excavating and studying the many sites, the ASU team gained valuable insight into several previously unanswered questions. They concluded that the Salado civilization came mostly from the Phoenix Basin, home of the Hohokam, not the Colorado Plateau, home of other groups such as the Anasazi.

“These people came from the southwest and northwest, but not the northeast,” Rice says.

Artifacts on display at the museum include a variety of crafts and the tools used to make those craft items. The scientists also found animal carvings, shell and stone ornaments and jewelry, and many pieces of the beautifully decorated polychrome pottery for which the Salado were widely known.—Matthew Shindell