photo by Rod Lauffer

In November 1999, petrologist Beth Miksa began collecting over 240 sand samples from along the entire San Pedro River Valley in Arizona and Mexico. Her innovative petrofacies research will play an important part in the Center's current investigations of the Late Classic Period in the region.

The composition of sands from washes running into the San Pedro River is highly variable. Through the petrofacies technique, differences in texture, size, shape, and composition of grains in each sand sample can be identified under a microscope. These differences combine to create a distinctive, recognizable "fingerprint" for sand originating in specific areas along the river valley.

The first step is to characterize modern sand samples. Then Dr. Miksa will examine the sand tempers found in prehistoric sherds from the valley. She will study the ceramics recovered during the Center's recent test excavations, and will re-examine pottery from past excavations that is curated at the Amerind Foundation and other museums. By matching the sand temper seen in these sherds with the "fingerprints" of the present-day sand samples, we hope to pinpoint specific areas of prehistoric ceramic production along the river. And, by comparing where a specific pot was made with where it was found by archaeologists, we may gain interesting insights into how the prehistoric people of the area were trading and interacting with each other.

This petrofacies research is made possible by a grant from the National Science Foundation.