Question

A common use of magnetism explorations is to locate hearths in archeological studies . In a short paragraph , explain why / how there would be a magnetic anomaly associated with hearths

Answer 1

Answer : Hearths and kilns are certain features associated with burning. They contain considerable amount of iron oxides (e.g : rocks, soils), as a result of which exposing these materials to intense heat can cause a detectable magnetic anomaly to build up which can then remain for about thousands of years even after the initial heating ceased to exist. This is mainly attributed to the changes that have occurred in the magnetic oxides during burning. Thermoremnant magnetization(TRM) makes up an important component of any in situ hearth magnetic anomaly, which is basically characterized by a permanent magnetic direction which was set during the time of cooling (that represents the ambient magnetic field since the last firing event). These intense magnetic anomalies usually associated with hearths are often largely attributed to TRM.