Some observations on short-term magnetic viscosity behaviour at room temperature

Experimental results on short-term magnetic viscosity behaviour at room temperature are described. A simple method, using a Digico spinner magnetometer, is used to measure short-term magnetic moment decays. These decays follow linear relationships with the logarithm of time showing relaxation times of less than 100–1000 s, i.e. superparamagnetic grain assemblages at room temperature. These effects are found to be very common in a wide variety of rock types, and may affect routine measurements of remanent magnetization.