Geophysical exploration of Guajara, a prehistoric earth mound in Brazil

An interdisciplinary team studied Guajara, a prehistoric artificial mound in the Brazilian Amazon. The geophysical surveys and excavations were interactive; this interaction furnished more information than either geophysics or excavation alone could have provided. While seven different geophysical methods were applied, the magnetic survey reported here was particularly valuable. A detailed interpretation of this survey quantified the magnetic material in the mound, and this furnished an initial estimate of the number of cooking hearths in the mound. Ten test excavations were concentrated at magnetic anomalies. These excavations located cooking hearths and burial urns. A reevaluation of the magnetic survey was then done in order to refine the estimate of the number of hearths in the mound; this yielded an estimate of 2200 hearths. This allowed the population of the site to be approximated at 78-156 people. The geophysical survey and excavations also identified possible locations for subsequent broad-area excavations. (C) 2003 Wiley Periodicals, Inc.