1. Department of Geology, University of Otago, P.O. Box 56, 9054 Dunedin, New Zealand.
2. ALP-Alpine Laboratory of Paleomagnetism, 12016 Peveragno, Italy
3. School of Environment, University of Auckland, Private Bag 92019, New Zealand
4. D.S.T., Università di Torino, via Valperga Caluso 35, 10125, Italy