Doctoral Dissertation Research: Archaeomagnetism in the U.S. Southeast

University Of Arizona, Tucson AZ

Investigators

Abstract

Under the direction of Dr. Michael Schiffer, Ms. Stacey Lengyel will collect and analyze data necessary for the completion of her doctoral dissertation. This project seeks to provide archaeologists working in the U.S. Southeast with a new way to date their archaeological findings. The technique that will be established through this project is called archaeomagnetic dating, and it uses preserved records of changes in the position of the earth's magnetic north pole to date burned, clay-rich archaeological features such as cooking hearths, pottery kilns, or the walls and floors of burned structures. This technique has been used successfully over the past 30 years to date sites throughout the U.S. Southwest, Europe and Japan, and this project aims to make the dating technique possible in the U.S. Southeast as well. Archaeomagnetic dating depends on 1) the fact that the earth's magnetic north pole drifts around the geographic rotation axis on the order of decades, and 2) the fact that burned, clay-rich archaeological features, such as cooking hearths, accurately record the position of the magnetic north pole at the time they were last fired (e.g., the last time a cooking hearth was used). When enough archaeomagnetic directional data are collected from well-dated archaeological features (e.g., a cooking hearth that also yielded a radiocarbon date) in a given region, a master record of archaeomagnetic change can be constructed in the form of a regional reference curve. However, due to local variations in the magnetic field, each reference curve is only valid over a 2000-km wide region. Therefore, the goal of this project is to construct the reference curve for the Southeast, thus making archaeomagnetic dating possible in this region. This project is important because it will provide archaeologists working in the U.S. Southeast with a means of establishing, verifying, and refining the temporal frameworks needed to address basic anthropological questions about past cultures. By furnishing researchers with tighter temporal control over the archaeological data, the regional archaeomagnetic curve developed through this project will allow archaeologists to examine the play of sociocultural processes across time and space and at a variety of scales, ranging from the sub-site level (e.g., between structures) to the pan-continent level (e.g., between the Tennessee River Valley and the Phoenix Basin). In short, the completion of the Southeast archaeomagnetic curve will provide researchers with an independent dating method that not only complements existing chronometric tools, but, when used in conjunction with those tools will allow for more temporally refined treatments of prehistoric cultural processes. This award will also assist in training a promising young scientist.