In the United States archaeomagnetism has been used primarily as an archaeological dating technique and has seldom been used to study the Earth's magnetic field. This project will use well- dated archaeological sites to acquire archaeomagnetic data relating to three problems: 1) the direction and intensity of the field at spot locations in the Western Hemisphere between 1550 and 1800 A.D., 2) the continuous record of directional changes in the American Southwest from 200 B.C.. to 1800 A.D., and 3) the record of intensity changes over the past 10,000 years in North and South America. In each case archaeomagnetism can clarify important questions about the behavior of the Earth's magnetic field that have arisen from recent advances in the study of historical records, rapidly-deposited sediments and lava flows. Although standard archaeomagnetic procedures will be followed during the course of the investigation, an important additional component will be detailed studies of the magnetic mineralogy and rock magnetic properties of various samples. These studies, which have never been done systematically for archaeomagnetic materials, will provide a firmer paleomagnetic basis for the measurements which we make and will provide new insights into the relative merits of different archaeological materials and archaeomagnetic techniques.
