1. Kennett, J. P. Marine Geology, 492–503 (Prentice-Hall, Englewood Cliffs, 1982).
2. Klinkhammer, G. & Hudson, A. Earth planet. Sci. Lett. (in the press).
3. Bostrom, K. Nature 227, 1041 (1970).
4. Lonsdale, P. Init. Rep. DSDP Leg 92, (in the press).
5. Leinen, M. et al. Init. Rep. DSDP Leg 92 (in the press).