Repeated progressive heating in susceptibility vs. temperature investigation: a new palaeotemperature indicator?

In the most rocks, the heating segment of the curve representing the bulk magnetic susceptibility to temperature relationship is very different from the cooling segment, indicating phase and/or compositional changes imposed by heating. On the other hand, repeated run usually results in converging heating and cooling curves. It is hypothesized that the same effect may work also in the nature. Up to the temperature undergone by the rock in the nature, the heating and cooling curves should be near each other, while they should differ substantially above this temperature. If the specimen is heated repeatedly and progressively from room temperature to 700 degreesC, one can discover the temperature above which the heating and cooling curves start to differ substantially and identify the temperatures undergone by the rock in the nature. (C) 2003 Elsevier Ltd. All rights reserved.