Figure F2. Representative thermomagnetic curves (left column) and thermal demagnetization of low-T isothermal remanent magnetization (IRM) (right column) for three types of Leg 187 samples. A. Pillow basalt: thermomagnetic curve on heating shows Curie temperature at ~250°C and a reaction maximum at elevated temperature; cooling curve is irreversible; low-T IRM curve is monotonous. B. Massive flow: almost reversible thermomagnetic curves showing ~170°C Curie temperature; low-T IRM curve showing stepping down at ~55 K. C. Metadiabase: thermomagnetic curves showing two Curie points at ~370° and ~580°C; low-T IRM curve showing phase transition at ~120 K. Vertical axis for the strong-field magnetization is arbitrary and that for low-T IRM is normalized for the value at 5 K.

Figure F2. Representative thermomagnetic curves (left column) and thermal demagnetization of low-T isothermal remanent magnetization (IRM) (right column) for three types of Leg 187 samples. A. Pillow basalt: thermomagnetic curve on heating shows Curie temperature at ~250°C and a reaction maximum at elevated temperature; cooling curve is irreversible; low-T IRM curve is monotonous. B. Massive flow: almost reversible thermomagnetic curves showing ~170°C Curie temperature; low-T IRM curve showing stepping down at ~55 K. C. Metadiabase: thermomagnetic curves showing two Curie points at ~370° and ~580°C; low-T IRM curve showing phase transition at ~120 K. Vertical axis for the strong-field magnetization is arbitrary and that for low-T IRM is normalized for the value at 5 K.