MAGNETIZATION DATING AT A MEDIEVAL MONASTERY (TUPHOLME,LINCOLNSHIRE)*

Tupholme Abbey, founded by c. 1166, was constructed of limestone masonry, some of which was reoriented at several times through its history. The limestone progressively acquired a ‘soft’, time-dependent magnetization in the earth's magnetic field—viscous remanent mag-netization (VRM)—that acts like a clock. Although VRM is normally disregarded by geologists because of its ephemeral nature, this remanence is acquired and persists over time-scales that are useful to archaeologists. Successive VRMs were initiated, at different ages of stabilization of the masonry, thus yielding a chronometric curve that allows us to determine, at least relatively, when masonry was installed.