The most important magnetic mineral in the fine-grained marls of the Early Pliocene Trubi formation near Eraclea Minoa is magnetite. Some goethite is also present. The magnetite is of high purity and of primary origin.

Hysteresis and low-temperature measurements show that most magnetite grains are single-domain. The presence of superparamagnetic grians is suspected. Multi-domain grains are rare. It is shown that AE demagnetization does not yield correct NRM directions. ¿ American Geophysical Union 1990