S.O. Schlanger M. Baltuck J.A. Bergen W. Dean P.A. Floyd N. Fujii J.A. Haggerty James G. Ogg I. Premoli-Silva A. Schaaf R.G. Schaefer W.V. Sliter J.M. Whitman R. Moberly 1983 [No abstract available] application/pdf 10.1038/302381a0 en Deep-sea Drilling Project Leg 89: The Mesozoic superocean article