Sedimentary rocks of pelagic and ocean ridge affinity interbedded with or overlying the volcanic sequence at the top of the Oman ophiolite contain datable radiolarian faunas that indicate (1) that the lavas were erupted in an oceanic environment during a narrow time interval ranging from the early Cenomanian to the early Turonian and (2) that the age progression within this volcanic sequence matches its development from a ridge axis to an off-axis setting. Emplacement of the ophiolite has been dated as late Campanian-early Maestrichtian et al., 1974>; thus the time gap between formation and emplacement was very narrow.